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This study compared angiotensin II (Ang II) and angiotensin III (Ang III) for their effects on rat neonatal cardiomyocytes and cardiac fibroblasts in vitro and discussed the possible role of Ang III in the pathogenesis of cardiac remodeling. To do so, protein synthesis, cardiac fibroblast proliferation, collagen synthesis, and secretion in response to treatment with Ang III and Ang II were investigated. Protein synthesis rate was assessed by 3H-Leucine (3H-Leu) incorporation; the content of DNA was defined by 3H-thymidine (3H-TdR) incorporation; and collagen synthesis and secretion were assessed by 3H-proline (3H-Pro) incorporation. In neonatal cardiomyocytes, Ang III stimulated protein synthesis in a concentration-dependent manner, whereas in neonatal cardiac fibroblasts, DNA synthesis as well as collagen synthesis and secretion were increased in a concentration-dependent manner. Treatment with captopril, selective aminopeptidase A (APA) inhibitor (EC33), or selective aminopeptidase N inhibitor (PC18) had no effect on these outcomes. Treatment with losartan significantly decreased the effects of Ang III, except for cardiomyocyte protein synthesis. Compared with Ang II, Ang III could stimulate cardiomyocyte protein synthesis, cardiac fibroblast proliferation, and collagen synthesis and secretion. Furthermore, 10-7 mol/L Ang II but not Ang III significantly increased APA activity in both cardiomyocytes and fibroblasts. All these results show the bioactive effects of Ang III on myocardial cells and suggest that Ang III could be an important independent factor besides Ang II in the regulation of cardiac function and may affect the pathogenesis of cardiac remodeling.

Apelin, the endogenous ligand of the G protein-coupled APJ receptor, is a peptide mediator with emerging regulatory actions in the heart. We aimed to determine whether the endogenous apelin/APJ system is an intrinsic protective pathway in ischemic/reperfusion injury. A Langendorff model of perfused isolated rat hearts and primary cultured myocardial cells from neonatal rats were used. Cardiac function was monitored and apelin/APJ expression was determined by real-time PCR and Western blot analysis. In rats under I/R, cardiac function was significantly decreased as compared with controls, and APJ was over-expressed at both the mRNA and protein levels (by 7-fold and 35%, respectively, both p

Proliferation and migration of vascular smooth-muscle cells (VSMCs) are essential events in neointimal hyperplasia. Recent findings that active oxygen species induce pro-oncogene expression, and stimulate VSMC DNA synthesis and cell division, suggest that active oxygen species may play an important role in intimal proliferation after arterial injury. To determine how the redox state of the artery was altered by injury, the levels of thiobarbituric-acid-reactive substances (TBARs, markers of lipid oxidation) and glutathione peroxidase (GSH-PX, the enzyme responsible for the production of glutathione, a major intracellular antioxidant) were measured in the rat aorta after balloon injury. There was an inverse relationship between the level of TBARs, which increased significantly to a maximum 17% greater than normal at 10 days after injury (p0.05, n=7), and the activity of GSH-PX, which decreased significantly to a minimum 36.5% less than normal at 10 days after injury (p0.05, n=7). To determine whether maintaining a more reduced vessel environment would inhibit intimal proliferation, L-cysteine was administered by intraperitoneal injection from 3 days before to 14 days after balloon injury. At 14 days after the arterial injury, the aorta was harvested for histological and morphometric measurements of TBARs and GSH-PX. At 7 and 14 days after balloon injury, the aorta was harvested for [3H]thymidine incorporation studies. Efficacy of therapy was demonstrated by a significant decrease in the level of TBARs and an increase in the activity of GSH-PX (p0.05 vs. the control group, n=7). In the L-cysteine group, all parameters of intimal proliferation were significantly reduced compared to the controls, including the intima:media ratio (0.091 vs. 0.253, p0.05); the cross-sectional area of the neointima (0.0563 compared to 0.140 mm2, p0.05), coverage of the internal elastic lamina by the neointima (23.44 compared to 43.27%, p0.05), and [3H]thymidine incorporation (at 7 days 240.58 vs 350.68 cpm/mg tissue, p0.05; at 14 days 181.71 vs. 275.30 cpm/mg tissue, p0.05). These results demonstrate dynamic alterations in the vessel redox state after arterial injury, and suggest that maintaining a more reduced environment (e.g. administration of L-cysteine) will reduce intimal proliferation after arterial injury.

To explore the impact of sulfur dioxide (SO(2)) on hydrogen sulfide (H(2)S)/cystathionine-γ-lyase (CSE) and H(2)S/mercaptopyruvate sulfurtransferase (MPST) pathways in the pathogenesis of hypoxic pulmonary hypertension.Thirty-two male Wistar rats were randomly divided into four groups: control group (n = 8), hypoxic group (n = 8), hypoxic + SO(2) group (n = 8) and hypoxic + hydroxamate (HDX) group (n = 8). After 21 days of experiment, the concentration and production of H(2)S in lung tissues were measured respectively for each rat. The protein expression of CSE and MPST in intima and media of small pulmonary arteries in rats was detected with immunohistochemical method.Compared with control group, the mean pulmonary artery pressure (mPAP) in rats of hypoxic group was increased significantly [(33.38 ± 6.32) mm Hg vs. (16.74 ± 3.81) mm Hg, P0.01]. Compared with hypoxic group, the mPAP in rats of hypoxic + SO(2) group was decreased significantly [(29.65 ± 2.53) mm Hg vs. (33.38 ± 6.32) mm Hg, P0.01]. However, compared with hypoxic group, the mPAP in rats of hypoxic + HDX group was increased significantly [(39.44 ± 6.26) mm Hg vs. (33.38 ± 6.32) mm Hg, P0.01]. Compared with control group, the concentration [(2.02 ± 0.43) µmol/g vs. (3.11 ± 0.42) µmol/g, P0.01] and production [(19.64 ± 3.48) nmol/(g·min)vs. (28.20 ± 5.95) nmol/(g·min), P0.05] of H(2)S were decreased significantly in rats of hypoxic group, respectively. When treated with SO(2), hypoxic rats showed an increased concentration [(2.73 ± 0.20) µmol/g vs. (2.02 ± 0.43) µmol/g, P0.01] and production [(26.24 ± 1.92) nmol/(g·min) vs. (19.64 ± 3.48) nmol/(g·min), P0.01] of H(2)S in lung tissue compared with those without receiving SO(2) treatment. When treated with HDX, hypoxic rats showed a significant decrease in concentration [(1.64 ± 0.23) µmol/g vs. (2.02 ± 0.43) µmol/g, P0.05] and production [(13.94 ± 3.63) nmol/(g·min) vs. (19.64 ± 3.48) nmol/(g·min), P0.05] of H(2)S in lung tissue compared with those without receiving HDX treatment. As for the expression of CSE in small pulmonary arteries (SPAs), compared with control group, the expression of CSE in intima [(0.31 ± 0.02) vs. (0.36 ± 0.01), P0.01] and media [(0.27 ± 0.01) vs. (0.30 ± 0.01), P0.01] in rats of hypoxic group was decreased significantly. While compared with hypoxic group, the expression of CSE in intima [(0.35 ± 0.02) vs. (0.31 ± 0.02), P0.01] in SPAs of hypoxic + SO(2) group was increased significantly. With HDX treatment, the expression of CSE in intima [(0.26 ± 0.01) vs. (0.31 ± 0.02), P0.01] in SPAs of hypoxic group was lower than that without HDX treatment. As for the expression of MPST in SPAs, compared with hypoxic group, the expression of MPST in media [(0.32 ± 0.02) vs. (0.29 ± 0.01), P0.01] in SPAs of hypoxic + SO(2) group was increased significantly.SO(2) might upregulate H(2)S/CSE and H(2)S/MPST pathways in pulmonary arteries of hypoxic rats.

To investigate the impact of human urotensin II (hUII) on pulmonary arterial smooth muscle cell (PASMCs) cycle in vitro.PASMCs dissected from Wistar rats were cultured in vitro, and incubated with series of concentrations of hUII (10(-7) mol/L, 10(-8) mol/L, 10(-9) mol/L) for 12 hours under normoxia or hypoxia condition, in order to analyze cell cycle progression and sub-G1 of PASMCs by using flow cytometric analysis stain of propidium iodide, which represented the proliferative and apoptotic changes in PASMCs.The study showed a dose-dependent effect of hUII on PASMCs proliferation, which reflected the increase both in percentage of S phase of cell cycle and proliferative index (PI). The response of PASMCs to hUII was different under normoxic and hypoxic conditions. Compared with the control group, the treatment of 10(-7) mol/L, 10(-8) mol/L and 10(-9) mol/L hUII produced an increase of 175%, 136% and 118% under normoxia, respectively, and 135%, 118% and 103% under hypoxia, respectively. The concentration 10(-7) mol/L hUII played a significant role in PASMCs proliferation both under hypoxia and normoxia (P0.01). The results of cell cycle did not show sub-G1 of PASMCs at various concentrations of hUII.hUII may stimulate DNA synthesis in S phase cell cycle of PASMCs and the proliferation of PASMCs under normoxia and hypoxia conditions, which promote cell growth in a dose-dependent manner.

To observe the effect of myocardial mitochondrial L-arginine (L-Arg)/nitric oxide (NO) system on mitochondrial Ca2+ transport by using purified rat mitochondria and incubation of them in vitro.Compared with control group, incubation of mitochondria with L-Arg (10(-4) mol/L, NO substrate) or sodium nitroprusside (5 x 10(-7) mol/L, the donor of exogenous NO, SNP) increased significantly mitochondrial NO2- (66% and 89%, P0.01), respectively, and decreased the Ca2+ content (40% and 54%, P0.01). After L-Arg or SNP treatment, mitochondrial Ca2+ uptake were decreased by 67% and 85%, respectively (P0.01), vs control. The rate of mitochondrial Ca2+ release decreased by 11% and 8%, respectively (P0.01). When L-NAME (NO synthase inhibitor) was incubated with mitochondria and the L-Arg together, it inhibited the effects of L-Arg, NO2 on the mitochondrial NO2 formation, Ca2+ content descending, and decrease of Ca2+ uptake and release.The data suggest that myocardial mitochondrial L-Arg /NO systems take part in the regulation of cardiomyocytes Ca2+ transportation.

To investigate the coordinated role and its mechanism of the high protein and hypercholesterol intake on inducing rat myocardial fibrosis.The tissue level of the collagen in left ventricule, the concentrations of the plasma and the cardiac tissue angiotensin II (Ang II) and Aldosterone (Ald), the serum concentration of nitrite (NO2-), in the Wistar rats on diet which adding 20% protein or/and 100 mg/d cholesterin in the rat standard foods for 8 weeks, were measured by the colorimetric analysis of the hydroxyproline, by the radioimmunoassay, and by the assay of Griess, respectively.1.69 times left ventricular collagen contents, 0.7 times plasma concentrations of total cholesterin, 1.5 times levels of the plasma Ang II and 1 time myocardial ald contents were higher, and the serum NO2- concentration was significant lower, in the rats of the high protein and hypercholesterol intake than in the rats of the high protein intake. That 0.48 times left ventricular collagen contents, 0.23 times plasma Ang II in the high protein and hypercholesterol intake rats were higher than in the high cholesterin intake rats.The excessive protein and cholesterin intake can induce the coordinated effect on developing the myocardial fibrosis of rats. And the mechanism of the fibrosis in rat left ventricule maybe result with the activation of RAAS and the endothelial injury.

Hydrogen sulfide (H(2)S) dilates blood vessels in vivo and in vitro probably by opening vascular smooth muscle K(+)-ATP channels. The study was designed to observe the role of mitochondria membrane K(ATP) channel blocker (5-HD) in the regulation of cardiac function isolated perfused heart of rat with H(2)S.The isolated rat heart was perfused in a Langendorff apparatus. After 20 minutes of stabilization, physiological concentration of NaHS (H(2)S donor, 100 micromol/L) was continuously perfused for 20 min in group A (n = 6), isolated hearts in group B (n = 6) and C (n = 7) were pretreated with nonspecific K(ATP) channel blocker glibenclamide (100 micromol/L) or 5-HD (100 micromol/L) for 5 minutes then perfused with NaHS (100 micromol/L) for 10 minutes. Heart rate (HR), left ventricular developed pressure (DeltaLVP), dp/dt(max) and dp/dt(min) and coronary perfusion flow (CPF) were measured.Post continuous perfusion of NaHS at physiological concentration for 20 minutes, DeltaLVP, dp/dt(max) and dp/dt(min) all significantly decreased while HR and CPF remained unchanged compared to baseline levels (all P0.05). The negative inotropic effect of H(2)S could partly be blocked by nonspecific K(ATP) channel blocker glibenclamide and mitochondria membrane K(ATP) channel blocker 5-HD.Present findings suggested that H(2)S at physiological concentration could produce negative inotropic effect in isolated hearts and this effect was mediated by K(ATP) channel and mitochondria membrane K(ATP) channel.

Hypoxic pulmonary hypertension is an important pathophysiologic process of various cardiovascular diseases. Sulfur dioxide (SO2) was considered as a kind of toxic gas previously, but recent studies suggested that SO2 could act as a key bioactive molecule in the pathogenesis of cardiovascular diseases. Therefore, this study was designed to examine the effect of sulfur dioxide on pulmonary vascular structure of hypoxic pulmonary hypertensive rats treated with SO2 donor substances.The rats were randomly divided into 3 groups: control group(n = 8), hypoxic group(n = 8) and hypoxic + SO2 group (n = 10, treated with SO2 donor Na2SO3/NaHSO3). The rats of hypoxic group and hypoxic + SO2 group were under a hypoxic condition for 21 days, while the rats of control group were exposed to room air. The mean pulmonary artery pressure was tested by means of right cardiac catheterization and the content of SO2 in plasma was investigated by high performance liquid chromatography (HPLC). The change in relative medial thickness (RMT) of pulmonary arteries was examined under optical microscope. The ultra-structural changes were observed under a transmission electron microscope. The data were analyzed through one-way analysis of variance (ANOVA) by SPSS 13.0 software.Compared with control group [(2.25 +/- 0.50) kPa], the mean pulmonary artery pressure of hypoxic group [(5.12 +/- 0.51) kPa] raised significantly (t = 5.091, P0.01) and RMT of hypoxic group (9.66 +/- 1.27) compared with control group (6.83 +/- 1.57) significantly raised (t = 3.392, P0.01). Ultrastructural observation showed the proliferation and degeneration of endothelial cells in small pulmonary arteries in rats with pulmonary hypertension. The internal elastic lamina was irregular. The proliferation of medial smooth muscle cells of arteries was shown at the level of respiratory bronchioles. The collagens also increased. Meanwhile, compared with control group [(33.36 +/- 5.62) micromol/L], the content of SO2 in plasma of hypoxic group [(27.01 +/- 4.17) micromol/L] declined (t = 2.067, P0.05). Whereas compared with that of hypoxic group [(5.12 +/- 0.51) kPa], the mean pulmonary artery pressure of hypoxic + SO2 group [(3.94 +/- 0.33) kPa] declined (t = 2.712, P0.01) and RMT of hypoxic + SO2 group (6.97 +/- 1.83) decreased compared with hypoxic group (9.66 +/- 1.27) (t = 3.009, P0.01). Compared with those of hypoxic group, the pulmonary artery ultrastructural changes in hypoxic group ameliorated obviously after using exogenous sulfur dioxide donor. The endothelial cells became flat and the smooth muscle cells of arteries slightly enlarged and arranged regularly. At the same time, compared with hypoxic group [(27.01 +/- 4.17) micromol/L], the content of SO2 in plasma of hypoxic + SO2 group [(29.89 +/- 4.52) micromol/L] raised (t = 1.263, P0.05).Sulfur dioxide plays an important role in the regulation of small pulmonary artery structural changes in hypoxic pulmonary hypertensive rats. The hypoxic pulmonary hypertensive damages can be ameliorated significantly after using exogenous SO2 donor.

The present study aimed to explore the protective effect of endogenous sulfur dioxide (SO2) in the development of monocrotaline (MCT)-induced pulmonary hypertension (PH) in rats.Forty Wistar rats were randomly divided into the MCT group receiving MCT treatment, the MCT+L-aspartate-beta- hydroxamate (HDX) group receiving MCT plus HDX treatment, the MCT+SO2 group receiving MCT plus SO2 donor treatment, and the control group. Mean pulmonary artery pressure (mPAP) and structural changes in pulmonary arteries were evaluated. SO2 content, aspartate aminotransferase activity, and gene expression were measured. Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), reduced glutathione (GSH), oxidized glutathione, and malondialdehyde (MDA) levels were assayed.In the MCT-treated rats, mPAP and right ventricle/(left ventricle+septum) increased significantly (P0.01), pulmonary vascular structural remodeling developed, and SOD, GSHPx, CAT, GSH, and MDA levels of lung homogenates significantly increased (P0.01) in association with the elevated SO2 content, aspartate aminotransferase activity, and gene expression, compared with the control rats. In the MCT+HDXtreated rats, lung tissues and plasma SO2 content and aspartate aminotransferase activities decreased significantly, whereas the mPAP and pulmonary vascular structural remodeling were markedly aggravated with the decreased SOD, CAT, and GSH levels of lung tissue homogenates compared with the MCT-treated rats (P0.01). In contrast, with the use of a SO2 donor, the pulmonary vascular structural remodeling was obviously lessened with elevated lung tissue SOD, GSH-Px, and MDA content, and plasma SOD, GSH-Px, and CAT levels.Endogenous SO2 might play a protective role in the pathogenesis of MCT-induced PH and promote endogenous antioxidative capacities.

To observe the effects of sulfur dioxide (SO2) on cardiac function of isolated perfused heart of rat and to explore the physiological regulation of endogenous SO2 on myocardial action.The hearts of 64 Wistar rats were isolated, perfused with Krebs-Henseleit (KH) solution through Langendorff apparatus, and randomly divided into 8 equal groups: Four groups underwent perfusion of SO2 of the concentrations 1, 10, 100, 1000 micromol/L respectively for 5 min and then perfused with KH solution for 15 min. Eight hearts underwent perfusion of SO2 of the physiological concentration (10 micromol/L) for 20 min. The control group underwent perfusion of KH solution for 20 min. Eight hearts of the nicardipine group underwent perfusion of nicardipine, a L-type calcium channel blocker, 2.5 micromol/L for 5 min, SO2 10 micromol/L for 5 min, and then KH solution for 10 min. The heart in the hydroxamate (HDX) group underwent perfusion of HDX, an inhibitor of SO2 endogenous generating enzymes, for 5 min, and then perfused by KH solution for 15 min. The heart rate (HR), difference of left ventricular pressure (LVP), left ventricular peak rate of contraction (+ dp/dtmax), peak rate of relaxation (- dp/dtmax), and coronary flow (CF) were measured. Then transmission electron microscopy was conducted.SO2 concentration-dependently inhibited the left ventricular +/- dp/dtmax, LVP, HR, and CF (all P0.01). The left ventricular +/- dp/dtmax, LVP, and HR were inhibited (P0.05) by the physiological concentration (10 micromol/L) SO2 donor continuous perfusion for 20 min. During perfusion 20 min, the LVP, + dp/dtmax, - dp/dtmax, and HR after perfusion for 20 min of the physiological concentration (10 micromol/L) SO2 donor continuous perfusion group were (15 +/- 3) mm Hg, (485 +/- 74) mm Hg/s, (339 +/- 64) mm Hg/s, and (114 +/- 26)/min respectively, all significantly lower than those 5 min after perfusion [(23 +/- 7) mm Hg, (595 +/- 93)mm Hg/s, (436 +/- 83) mm Hg/s, and (159 +/- 31)/min, all P0.05]. The LVP, + dp/ dtmax, -dp/dtmax, and HR of the nicardipine group were(37 +/- l0)mm Hg, (1025 +/- 287)mm Hg/s, (570 +/- 181)mm Hg/s, and (139 +/- 48)/min respectively, all not significantly different from those of the control group. The LVP, + dp/dtmax, - dp/dtmax, and CF after perfusion of the HDX group were (50 +/- 11)mm Hg, (1167 +/- 270) mm Hg/s, (889 +/- 72) mm Hg/s, and (6.3 +/- 1.9) ml/min respectively, all significantly lower than those before perfusion [(69 +/- 16) mm Hg, (1579 +/- 315) mm Hg/s, (1186 +/- 263) mm Hg/s, and (9.5 +/- 1.3) ml/min, all P0.05].Exogenous SO2 has negative inotropic effect on myocardium. by the mechanism related to voltage-gated calcium channel. Nicardipine blocks the inhibitory effect of SO2 at physiological concentration.

The present study was designed to explore the endogenous production and localization of the sulfur dioxide (SO2)/aspartate aminotransferase pathway in vascular tissues of rats and to examine its vasorelaxant effect on isolated aortic rings,as well as the possible mechanisms.The content of SO2 in the samples was determined by using high performance liquid chromatography with fluorescence detection. Aspartate aminotransferase activity and its gene expression were measured by an enzymatic method and quantitative RT-PCR, respectively. Aspartate aminotransferase mRNA location in aorta was detected by in situ hybridization. The vasorelaxant effect of SO2 on isolated aortic rings of the rats was investigated in vitro. L-type calcium channel blocker, nicardipine, and L-type calcium channel agonist, Bay K8644, were used to explore the mechanisms by which SO2 relaxed the aortic rings.Aorta had the highest SO2 content among the vascular tissues tested (P0.01). The aortic aspartate aminotransferase mRNA located in endothelia and vascular smooth muscle cells beneath the endothelial layer.Furthermore, a physiological dose of the SO2 derivatives (Na2SO3/NaHSO3) relaxed isolated artery rings slightly, whereas higher doses (1-12 mmol/L) relaxed rings in a concentration-dependent manner. Pretreatment with nicardipine eliminated the vasorelaxant response of the norepinephrine-contracted rings to SO2 completely. Incubation with nicardipine or SO2 derivatives successfully prevented vasoconstriction induced by Bay K8644.Endogenous SO2 and its derivatives have a vasorelaxant function, the mechanisms of which might involve the inhibition of the L-type calcium channel.

To study the modulatory effect of hydrogen sulfide (H(2)S) on oxidative stress in the development of pulmonary hypertension induced by hypoxia.Twenty male Wistar rats were randomly divided into control group (n=6), hypoxic group (n=6) and hypoxia+NaHS group (n=8). Hypoxic challenge was performed everyday for 21 days. NaHS solution was injected intra-peritoneally everyday before hypoxic challenge for rats in the hypoxia+NaHS group. After 21 days of hypoxia, the mean pulmonary artery pressure(mPAP) was measured by cardiac catheterization. The weight ratio of right ventricle to left ventricle+septum [RV/(LV+SP)] was also measured. The lung homogenates were assayed for total antioxidant capacity(T-AOC), superoxide dismutase (SOD), oxidized glutathione (GSSG), reduced glutathione (GSH), malondialdehyde(MDA) and hydroxy radical(*OH), and the SOD mRNA levels were assayed by real time polymerase chain reaction.After three weeks of hypoxic disposure, hypoxic hypertension and vascular remodeling developed. Compared with the control group, the mPAP[(23.7+/-2.2) mm Hg vs (16.3+/-3.7) mm Hg,P0.01] and the weight ratio of RV/(LV+SP) increased (P0.01), but lung tissue T-AOC was decreased by 21.4% (P0.01).But GSSG was increased by 68.5% (P0.01) as compared with those of the control rats. However, compared with those of the hypoxic group, the mPAP in rats of hypoxia+NaHS group was decreased [(16.3+/-2.8) mm Hg vs (23.7 +/-2.2) mm Hg]. Administration of NaHS increased T-AOC by 18.8% (P0.05) but eliminated GSSG by 23.2% (P0.05) in rats of hypoxia+NaHS group as compared with the hypoxic group. There were no significant changes in lung tissue SOD mRNA level and its capacity among the three groups.Hydrogen sulfide acted as antioxidant during the oxidative stress of hypoxic pulmonary hypertension, and the mechanism was partly through attenuating the content of GSSG.

To investigate the effects of intermedin 1-53 on oleic acid induced acute lung injury (ALI) in rats and its possible mechanisms.Twenty-four male Wistar rats, weighting 280-300 g, were randomly divided into three groups (n = 8). In the oleic acid group, ALI was induced by injecting oleic acid (0.2 ml/kg) intravenously. In the intervention group, the rats received oleic acid as above, but intraperitoneal injection of intermedin 1-53 (2 nmol/kg in l ml saline) was given 1 h before and 2 h after oleic acid infusion, respectively. The control group was given normal saline (0.2 ml/kg). The animals were observed for 6 h after intravenous infusion. The histopathological changes of lung tissue were studied. The arterial blood gases, lung wet/dry weight ratio (W/D), leukocyte count and neutrophil differentials in bronchoalveolar lavage fluid (BALF) were measured. Contents of intermedin 1-53 in the plasma were detected with radioimmunoassay, myeloperoxidase activity, and malondialdehyde (MDA) and conjugated diene (C-diene) level of lung tissue were also measured.The PaO(2) was higher and lung wet/dry weight ratio, leukocyte count and neutrophil counts in BALF were significantly lower in the intermedin group [(81.7 +/- 4.6) mm Hg (1 mm Hg = 0.133 kPa), 5.49 +/- 0.63, (57.9 +/- 7.4) x 10(4)/ml, 0.718 +/- 0.085, respectively] as compared to the oleic acid group [(60.8 +/- 3.2) mm Hg, 6.18 +/- 0.34, (122.0 +/- 16.6) x 10(4)/ml, 0.878 +/- 0.026], q value was 16.74, 3.43, 17.23, 6.32, respectively, all P0.05 or 0.01).Intermedin 1 - 53 treatment significantly attenuated oleic acid-induced lung injury in rats. Intermedin 1-53 exerts pulmo-protective effects by inhibiting formation of lipid oxide products.

To investigate the vasorelaxant effect of sulfur dioxide (SO(2)) on isolated aortic rings of rats in vitro and its relaxation mechanisms.We perffused the isolated aortic rings of rats, and precontracted the rings with noradrenaline (NE), then observed the relaxant reactivity of SO(2) derivatives, mixture of sulfite and hydrogen sulfite [Na(2)SO(3)/NaHSO(3) 3:1(amount of substance)], to the aortic rings. Meanwhile, we studied the influence of glibenclamide and nicardipine, blockers of K(ATP) and L-calcium channels, on the vasorelaxant reactivity of SO(2) derivatives. We further incubated the aortic rings with hydroxamate (HDX), the inhibitor of SO(2) endogenous generating enzymes, and SO(2) derivatives (4 mmol/L) in vitro, then observed the contraction of the aortic rings to NE.Isolated aortic rings of rats exhibited relaxant reactivity to Na(2)SO(3)/NaHSO(3) (0-12 mmol/L) in a concentration-dependent manner. IC(50) of the relaxation curve was (7.28+/-0.12) mmol/Lìand Emax was 78.79%+/-3.24%. Glibenclamide (1x10(-6) mol/L) inhibited the vasorelaxation to low dose Na(2)SO(3)/NaHSO(3) (or=4 mmol/L), whereas it failed to inhibit the vasorelaxation to high dose of Na(2)SO(3)/NaHSO(3) (6 mmol/L). Nicardipine (1x10(-9) mol/L) could decrease the contraction of the rings to NE, and even could inhibit the relaxation of Na(2)SO(3)/NaHSO(3) almost completely. The inhibition of the endogenous SO(2) production with HDX (1x10(-4) mol/L), resulted in an increase in the contraction of rings. The contraction curve to NE shifted to the left, and IC(50) also changed from (6.48+/-0.84)x10(-7) mol/L to (3.97+/-1.63)x10(-7) mol/L (P0.01). However, after the incubation of aortic rings with Na(2)SO(3)/NaHSO(3) (4 mmol/L), the contraction curve to NE shifted to the right, and IC(50) changed from (6.48+/-0.84)x10(-7) mol/L to (4.93+/-0.81)x10(-5) mol/L (P0.01).SO(2) could relax vascular smooth muscles, and the mechanism might be associated with calcium channels and K(ATP) channels, suggesting that endogenous SO(2) could modulate the cardiovascular function.

To investigate the changes of pulmonary IMD and its receptor system-calcitonin receptor-like receptor (CL) and receptor activity modifying proteins (RAMPs) mRNA in acute lung injury(ALI) induced by oleic acid of rats.Contents of IMD in plasma and lung homogenates were measured by radioimmunoassay(RIA). The lung mRNA of IMD, CL and RAMPs was determined by semi-quantitative RT-PCR.Compared with control group, in ALI group, the contents of IMD1-53 in plasma and lung homogenates were decreased by 20.8% and 74.5% (all P0.05) , respectively. Furthermore , it was found that the levels of IMD, CL, RAMP1 and RAMP2 mRNA in lung were decreased by 30%, 38%, 26% and 37.9% (all P0. 05) , respectively. The levels of CL , RAMP1 or RAMP2 mRNA were positively correlated with down-regulations of IMD mRNA in ALI. However, compared with control group, the maximum binding capacity of IMD1-53 to plasma membranes was significantly increased in ALI group, and the affinity of IMD1-53 for its receptor almost had no change.The amount of IMD 1-53 is down-regulated and IMD receptor system also down-regulated in Oliec acid induced ALI of rats. These changes suggest that IMD and its receptor system probably are involved in the development of ALI.

To investigate the effects of oxidized-low density lipoprotein (ox-LDL) and urotensin II (U II) on the proliferation of rat aortic smooth muscle cells (VSMCs) and the effect of ox-LDL on the mRNA expression of U II receptor GPR14 in.Rat VSMCs were incubated with UII and ox-LDL at different concentrations. The viability of rat VSMCs was detected by MTT assay. Rat VSMCs were incubated with ox-LDL at the concentrations of 0, 0.1, 1, 10, and 50 microg/ml. Twelve hours later competitive RT-PCR was used to detect the effects of concentration of ox-LDP on the mRNA expression of GPR14 in the VSMCs. Another VSMCs were incubated with ox-LDL at the final concentration of 50 microg/ml, and 0, 2, 6, 12, and 24 hours later competitive RT-PCR was used to detect the mRNA expression of GPR14 in the VSMCs. (125)I-labelled U II was added into the culture fluid of VSMCs, and radioligand binding assay was used to calculate the maximum binding (B(max)).UII of the concentration of 50 nmol/L significantly increased the proliferation of VSMCs. When the concentration of ox-LDL was 10 microg/ml the proliferation of VSMCs (P0.01) was 0.678 +/- 0.061, increased by 121% compared with the control group (0.325 +/- 0.052, P0.01). 0.01 microg/ml of ox-LDL and 10 nmol/L of UII showed a synergistic effect on the proliferation of VSMCs with the MTT value increased to 162% +/- 29% that of the control group (P0.01). When the concentration of ox-LDL increase to 0.1 microg/ml the synergistic effect was attenuated with the MTT value of 153% +/- 22% that of the control group (P0.05) and when the concentration of ox-LDL increased to 1 microg/ml the synergistic effect diminished, with a MTT value of 123% +/- 13% that of the control group (P0.05). When the concentration of ox-LDL was 50 microg/ml the proliferation of VSMCs the MTT value decreased to 59% that of the of control group, however, ox-LDL of the concentration of 50 microg/ml combined with UII of the concentration of 10 nmol/L the MTT value increased to 68% that of the control group, showing that UII of that concentration significantly inhibited the cytotoxic effect of ox-LDL. Incubation of VSMCs with the ox-LDL at the concentration of 0.1 microg/ml the GPR14 mRNA expression of the VSMCs was 125.1% that of the control group (P0.01) as assessed by competitive RT-PCR, however, when the concentration of ox-LDL increased over 1 microg/ml the GPR14 mRNA expression does-dependently decreased as much as 72.6% that of the control group (all P0.01), with the maximal effect when the concentration of ox-LDL reached 50 microg/ml. ox-LDL at the concentration of 50 microg/ml time-dependently down-regulated the GPR14 mRNA expression with the maximal effect 12 hours after addition of ox-LDL and this effect was sustained for up to 24 hours. After incubation for 12 hours the binding of (125)I-UII to VSMCs was 117.5% that of the control group (P0.01) with the ox-LDL at the concentration of 0.1 microg/ml, and was 68.8% that of the control group (P0.01) with the ox-LDL at the concentration of 50 microg/ml.ox-LDL and with U-II. GPR14 at certain concentrations show synergetic effects on the proliferation of VSMCs. The GPR14 mRNA expression in VSMCs can be upregulated by low concentration of ox-LDL, while downregulated by high concentration of ox-LDL.

To investigate the anti-cardiac hypertrophic mechanism of statins, thirty-eight male Wistar rats were randomly allocated to four groups. Rats in model group received nitric oxide synthase inhibitor, N-nitro-L-arginine (L-NNA) 15 mg/(kg.d) by peritoneal injection. Rats in simvastatin treatment groups were given simultaneously L-NNA as those in model group and simvastatin 5 or 30 mg/(kg.d) intragastrically respectively. Rats in control group received the same volume of normal sodium. Left ventricular function, left ventricular mass index (LVMI), the content of brain natriuretic peptide (BNP) in plasma and myocardium, myocardial hydroxyproline and heme oxygenase activity were determined after 6 weeks. The results showed that rats in model group developed significant cardiac hypertrophy associated with reduced left ventricular function compared with the control group. However, compared with the model group, L-NNA-induced cardiac hypertrophy of rats was significantly relieved in simvastatin treatment groups, associated with improved left ventricular function, decreased LVMI, lower BNP levels in plasma and myocardium, lower content of myocardial hydroxyproline, and increased myocardial heme oxygenase (HO) activity. In cultured rat neonatal cardiomyocytes, simvastatin (30 or 100 mumol/L) significantly increased heme oxygenase-1 (HO-1) mRNA expression, HO activity as well as the production of CO in cardiomyocytes. Cultured with zinc protoporphyrin, a HO inhibitor, or simvastatin alone did not change [(3)H]leucine uptake of cardiomyocytes. However, cocultured with simvastatin significantly inhibited the cardiomyocyte [(3)H]leucine uptake induced by angiotensin II in a concentration-dependent manner. Cotreatment with zinc protoporphyrin significantly abolished the suppressive effect of simvastatin on cardiomyocyte [(3)H]leucine uptake. These data suggest that the activation of HO-1/CO pathway may be one of the important mechanisms by which statins inhibit cardiac hypertrophy caused by hypertension.

To explore the change of endogenous hydrogen sulfide and the effect of exogenously applied H(2)S on Bleomycin-induced pulmonary fibrosis in rats.(1) Forty-eight male Wistar rats were randomly divided into control group, fibrosis group, fibrosis+NaHS-low group (1.4 micromol/kg, bid intraperitoneally) and fibrosis+NaHS-high group (7.0 micromol/kg, bid intraperitoneally). Pulmonary fibrosis was induced by intratracheal instillation of bleomycin. The control group and pulmonary fibrosis group were injected with the same volume of normal saline. Pulmonary pathology changes were observed, the plasma H(2)S concentration,the activity of CSE in lung tissue and the contents of MDA, hydroxyproline were detected on the 7th and 28th days respectively after bleomycin administration. CSE mRNA was also measured using quantitative RT-PCR. (2) Isolated lung tissues were exposed to Fe(2+)/H(2)O(2) without or with different concentrations of NaHS (10(-5), 5 x 10(-5), 10(-4), 10(-3) mmol/L) at 37 degree Celsius for 10 minutes, and the MDA content was assayed by biochemical method.(1) Compared with rats in control group, the concentration of plasma H(2)S and the activity of CSE in lung tissues in fibrosis group decreased on day 7 (all P0.01); On the 28th day, the level of plasma H(2)S increased clearly (P0.01) and the activity of CSE was ascendant without significant difference compared with that of control group. Relative CSE mRNA amounts in lung tissues increased 34%, 144%, respectively (all P0.01) in rats of fibrosis group compared with those of control group. The contents of MDA and hydroxyproline increased significantly in fibrosis group compared with those of control group on days 7, 28 (all P0.01). In NaHS-low group and NaHS-high group, the contents of MDA and hydroxyproline decreased markedly (all P0.01). (2) The contents of MDA in incubation of lung tissues at different concentrations of NaHS were all decreased as compared with those in incubation with Fe(2+)/H(2)O(2) alone (all P0.01). When NaHS was at 10(-4) mol/L, the MDA content reversed to the lowest value, which had the highest value at 10(-3) mol/L of NaHS.Endogenous CSE/H(2)S pathway was involved in the pathogenesis of rat pulmonary fibrosis. Exogenously applied H(2)S could attenuate the process of pulmonary fibrosis possibly because of reducing oxidative stress.

To explore the effect of adrenomedullin(1-50) (ADM(1-50)) on hypoxic pulmonary hypertension and pulmonary vascular structural remodeling and the plasma concentration of nitric oxide (NO) and hydrogen sulfide (H(2)S) in rats.Twenty male Wistar rats were randomly divided into control group (n=7), hypoxic group (n=6) and hypoxic with ADM(1-50) group (n=7). ADM(1-50) was subcutaneously administered into rats of hypoxic with ADM(1-50) group by mini-osmotic pump (300 ng/h). After two weeks' hypoxic challenge, mean pulmonary arterial pressure (mPAP) was evaluated by using a right cardiac catheterization procedure. The ratio of right ventricular mass to left ventricular plus septal mass [RV/(LV+S)] was detected. Pulmonary vascular microstructure was measured and the ultrastructural changes in intra-acinar pulmonary arteries were observed. Meanwhile, plasma concentrations of NO and H(2)S were measured.mPAP was significantly increased in hypoxic rats than that in controls [(24.9+/-6.8) mmHg vs (14.3+/-2.4) mmHg, P0.01,1 mmHg=0.133 kPa]; RV/(LV+S) was also significantly increased in hypoxic rats than that in controls [(0.318+/-0.054) vs (0.182+/-0.007), P0.01]. Microstructure and ultrastructure of pulmonary arteries changed obviously in hypoxic rats with the development of hypoxic pulmonary vascular structural remodeling. Meanwhile, plasma NO and H(2)S concentrations in hypoxic rats were markedly decreased compared with controls. However, mPAP was significantly decreased in hypoxic rats treated with ADM(1-50) than that in hypoxic rats [(14.9+/-3.0) mmHg vs (24.9+/-6.8) mmHg, P0.01]; RV/(LV+S) was also significantly decreased than that in hypoxic rats [(0.185+/-0.011) vs (0.318+/-0.054), P0.01]. ADM(1-50) ameliorated pulmonary vascular structural remodeling of hypoxic rats in association with an increase in plasma NO and H(2)S concentrations.ADM(1-50) plays an important role in regulation of the development of hypoxic pulmonary hypertension and hypoxic pulmonary vascular structural remodeling, through promoting NO and H(2)S production in hypoxic rats.

To study the effects of hyperhomocysteinemia on cardiac remodeling and systolic function.Twenty-four Wistar rats were divided randomly into experiment and control group. 12 rats of experiment group were bred with 1 g/(kg.d) L-methionine. After 4 weeks, 6 of them were killed (HHcy), others were continuously bred with normal diet for 4 weeks (Quit hcy, QHcy). Twelve rats of control group with normal diet for 4 and 8 weeks. The plasma Hcy concentrations were measured by immuno-fluorescence technique. Left ventricular structure and systolic function were assessed by echocardiography. The cardiac morphology and collagen were studied by optical microscopy and image analysis system after hematoxylin eosin-staining and picrosirius red-staining. Immuno-histochemistry for actin-smooth muscle and factor VIII-related antigen was performed to identify changes in cardiac smaller arteriolar and microvascular numbers.The plasma Hcy concentration was (106.19+/-19.75) micromol/L in HHcy, (6.52+/-0.94) micromol/L in QHcy and (4.90+/-0.10) micromol/L in the control. Left ventricular systolic function was decreased 10.7% in HHcy. Left ventricular wall strain and cardiac smaller arteriolar wall thickness were increased by 62.1% and 2.9 fold in HHcy, 27.1% and 2.4 fold in QHcy as compared with the control. Cardiomyocyte diameter was not changed in HHcy and increased by 15.4% in QHcy as compared with the control. Microvascular number was decreased by 45.9% in HHcy as compared with the control, but smaller arteriolar number did not differ among the groups. Left ventricular systolic function and microvascular number resumed in QHcy. Interstitial and perivascular collagen deposition was significantly increased in HHcy and QHcy.Hyperhomocysteinemia may increase cardiomyocyte diameter, cardiac smaller arteriolar wall thickness and left ventricular wall strain; decrease microvascular number; induce interstitial and perivascular collagen deposition, directly and indirectly affect on cardiac remodeling and systolic function. The cardiac remodeling couldn't resume completely with plasma Hcy concentration being decreased.

To determine the role of cross-talk between calcineurin-dependent signal transduction pathway and protein kinase C (PKC), mitogen-activated protein kinase (MAPK) and protein kinase A (PKA) in airway remodeling in asthma.Male guinea pigs were sensitized with intraperitoneal injections of ovabumin (OVA), then treated with cyclosporin A (CsA, 5 mg/kg), an inhibitor of calcineurin, then inhaled OVA for 2 weeks 14 days later. Activities of calcineurin, PKC, MAPK, and PKA were was analyzed by phosphorylation and dephosphorylation. In primary cultures of rat airway smooth muscle cells (ASMC), activities of calcineurin, PKC, MAPK, and cross-talk induced by urotensin II (UII ), a recently identified strong mitogen, were measured.(1) The activities of calcineurin, MAPK and PKC increased by 19% (P0.01), 28% (P0.01) and 35% (P0.05), respectively, in the asthmatic group compared with controls but decreased by 52% (P0.01), 18% (P0.05) and 52% (P0.01), respectively, in the CsA group compared with asthmatic group. PKA activity in the asthma group decreased by 53% (P0.01) compared with controls but increased by 2.65-fold (P0.01) in the CsA group compared with the asthma group. (2) UII 10(-7) mol/L stimulated ASMC PKC and MAPK activities by 44% and 24% (P0.01), respectively, after incubating for 20 min. It increased CaN activity in a time-dependent manner, being 1.67 times that of the control for 24 h (P0.01). (3) CsA 10(-6) mol/L and H(7) 50 micromol/L, an inhibitor of PKC, inhibited UII-stimulated CaN activity by 45% (P0.01) and 21% (P0.05), respectively, while PD(98059) 50 micromol/L, an inhibitor of MAPK, had no effect on CaN activity (P0.05). (4) CsA 10(-6) mol/L inhibited UII-stimulated PKC activity by 14% (P0.05), while having no effect on MAPK activity (P0.05).The signal transduction pathways between calcineurin and other protein kinases such as PKC, MAPK and PKA have cross-talk in airway remodeling in asthma.

To explore the impact of hydrogen sulfide (H2S) on the carbon monoxide (CO)/heme oxygenase-1 (HO-1) system in pulmonary artery of hypoxic rats.Twenty-seven rats were randomly divided into four groups: hypoxic group (n = 7), hypoxic + NaHS group (n = 7), hypoxic + propargylglycine (PPG) group (n = 6) and control group (n = 7). After 21 days, pulmonary artery mean pressure (mPAP) of each rat was evaluated and the plasma concentration of H2S and CO were measured. The expression of HO-1 in pulmonary arteries of each rat was detected by immunohistochemistry technique. In situ hybridization for HO-1 mRNA in pulmonary arteries was also observed.mPAP was significantly increased in hypoxic rats [(20.5 +/- 2.9) mm Hg] as compared with that of normal controls [(14.8 +/- 3.6) mm Hg, P0.05]. The plasma H2S[(196+/-22 ) micromol/L] of hypoxic group was decreased significantly compared with control group [(294+/-26) micromol/L, P0. 05]. The plasma CO and the expression of HO-1 protein and mRNA in large, medium and small sized pulmonary arteries of hypoxic group [ (0.348 +/- 0.021) micromol/L, 0.79+/-0.08, 0.77+/-0.08, 0.76+/-0.09, 0.813+/-0.052, 0.831+/-0.043, 0.819+/-0.032, respectively] were significantly increased compared to control rats [(0.313+/-0. 020) micromol/L, 0.66+/-0.08, 0.64+/-0.05, 0.54+/-0.05; 0.573 +/- 0.148, 0.532+/-0.131, 0.473+/-0.102, respectively; all P0.05]. Compared with hypoxic group, the plasma H2S of hypoxic + NaHS group [(324+/-33 ) micromol/L] was significantly increased, and mPAP was decreased significantly (all P0.05). Meanwhile, compared with hypoxic group, the plasma concentration of CO [(0.393+/-0.032) micromol/L], the expression of HO-1 protein and mRNA in large, medium and small sized pulmonary arteries were significantly increased in hypoxic + NaHS group (0.88+/-0.04, 0.89 +/- 0.05, 0.89 +/- 0.06; 0.913 +/- 0.022, 0.922 +/- 0.021, 0.933 +/- 0.014, respectively; all P0.05). However, compared with hypoxic group, the plasma concentration of H2S was decreased significantly in hypoxic + PPG group [(142 +/- 45) micromol/L, P0. 05], and mPAP was increased significantly (P0.05). With the decrease of H2S in hypoxic + PPG group, the plasma concentration of CO, the expression of HO-1 protein and mRNA in large, medium and small sized pulmonary arteries were significantly decreased [(0.274 +/- 0.032) micromol/L; 0.54 +/- 0.06, 0.56+/-0.04, 0.39+/-0.06; 0.423 +/- 0.043, 0.418 +/- 0.091, 0.382+/-0.051 respectively; all P0.05] compared to hypoxic group.H2S upregulated CO/HO-1 system in pulmonary arteries of hypoxic rats.

To observe the dynamic changes of plasma adrenomedullin (ADM) levels and the effect of enalapril intervention in diabetic rats.Fifty-two wistar rats were grouped into 1- and 3-month groups (7 each), both including a control and a streptozotocin-induced diabetic group. The 5-month group was divided into control, diabetic and enalapril-treatment diabetic groups (8 each, the last group receiving oral enalapril treatment at the daily dose of 2 mg/kg from the first to the fifth month after diabetes induction). Blood samples were collected from the heart of the rats at the end of 1, 3 and 5 months for determination of plasma ADM concentrations radioimmunoassay.Plasma ADM levels were significantly higher in diabetic rats than in the corresponding control rats in 1- and 3-month groups. ADM levels in the diabetic rats of 5-month group were significantly decreased in comparison with that of 1- and 3-month groups. In 5-month group, plasma ADM levels of enalapril-treated diabetic rats elevated significantly in comparison with that in the control rats and the diabetic rats without enalapril treatment.ADM may play an important role in the pathophysiology of diabetes.

To study the modulatory effect of hydrogen sulfide (H(2)S) on the accumulation of collagen type I and type III in the wall of pulmonary small artery during hypoxic pulmonary vascular remodeling.Nineteen male Wistar rats were randomly divided into a control group (n = 6), a hypoxic group (n = 7) and a hypoxia + NaHS group (n = 6). Hypoxic challenge was performed everyday for 21 days. NaHS solution was injected peritoneally everyday before hypoxia challenge for rats in the hypoxia + NaHS group. After 21 days of hypoxia, the mean pulmonary artery pressure was measured by pulmonary artery catheterization. The weight ratio of right ventricle to left ventricle + septum [RV/(LV + SP)] was also measured. The plasma level of H(2)S was determined by methylene blue spectrophotometric method. The expression of collagen type I and type III in pulmonary small arteries were detected by immunohistochemistry. The expression of procollagen type I and type III mRNA in pulmonary small arteries were detected by in situ hybridization.(1) Compared with the control group, the mPAP increased by 46% (P0.01), the weight ratio of RV/(LV + SP) increased by 41% and the plasma level of H(2)S decreased by 36% for rats in the hypoxia group (P0.01). Compared with the hypoxia group, the mPAP decreased by 31% (P0.01), the weight ratio of RV/(LV + SP) decreased by 24% and the plasma level of H(2)S increased by 65% (P0.01) for rats in the hypoxia + NaHS group. (2) Expression of collagen type I in small and median pulmonary arteries of the three groups: compared with rats in the control group, collagen type I expression increased by 81% and 62% respectively for rats in the hypoxia group (P0.01); compared with rats in the hypoxia group, the expression decreased by 32% and 18% respectively for rats in the hypoxia + NaHS group (P0.01). (3) Expression of procollagen type I mRNA in small and mid pulmonary arteries of the three groups: compared with rats in the control group, the expression increased by 49% and 68% respectively (P0.01) for rats in the hypoxia group; compared with rats in the hypoxia group, the expression decreased by 31% and 33% respectively for rats in the hypoxia + NaHS group (P0.01). (4) Expression of collagen type III in small pulmonary arteries of the three groups: compared with rats in the control group, the expression increased by 84% for rats in the hypoxia group (P0.01); compared with rats in the hypoxia group, the expression decreased by 37% for rats in the hypoxia + NaHS group (P0.01). Compared with rats in the control group, the expression of collagen type III in median pulmonary arteries increased by 38% in the hypoxia group (P0.01), while there was no significant difference between the hypoxia group and the hypoxia + NaHS group. (5) Expression of procollagen type III mRNA in small and median pulmonary arteries of the three groups: compared with rats in the control group, the expression increased by 53% and 17% respectively (P0.01) for rats in the hypoxia group; compared with rats in the hypoxia group, the expression decreased by 45% and 33% respectively for rats in the hypoxia + NaHS group (P0.01).In the process of hypoxic pulmonary vascular collagen remodeling in rats, H(2)S could inhibit the abnormal accumulation of collagen type I and type III in the wall of pulmonary small arteries. This effect may be one of the mechanisms by which H(2)S ameliorates hypoxic pulmonary vascular remodeling.

To investigate the effect of hypoxia/reoxygenation on endoplasmic reticulum stress in cultured neonatal rat cardiomyocytes.Neonatal rat cardiac myocytes in primary culture were exposed to hypoxia for 5.5 hours and subsequently reoxygenation for 2-24 hours. Western blot and RT-PCR were applied to monitor the expression change of GRP78 (glucose regulated protein 78). 2-deoxy-D-glucose (2-DG) was the positive control of this study. Then Western blot and RT-PCR were used to examine the expression of GRP78.Cell viability was decreased obviously after hypoxia/reoxygenation. Compared with untreated cells, the GRP78 content of the cells had increased significantly in the hypoxia/reoxygenation cells. The level of GRP78 protein and mRNA elevated from the points of 2 hours to 24 hours after reoxygenation, and increased most obviously at the point of 4 hours after reoxygenation. (4 hours: protein level 142% of the control, mRNA level 200%). 2-DG could induce the increasing expression of GRP78 in a concentration-dependent manner from 10-50 mmol/L.Hypoxia/reperfusion can induce endoplasmic reticulum stress in rat cardiomyocytes.

To explore the effects of hydrogen sulfide (H(2)S) on hypoxic pulmonary vascular smooth muscle cell (VSMC) apoptosis in rats.Twenty-four Wistar rats were divided into 3 groups: control group (n=8), hypoxia group (n=8), and hypoxia +NaHS group (n=8). The plasma level of H(2)S was determined by methylene blue spectrophotometric method. VSMC apoptosis was measured by terminal deoxynucleotidyl transferase-biotin nick end labeling (TUNEL). The protein expressions of Bcl-2, Fas and caspase-3 in pulmonary arteries were detected by immunohistochemical technique.Compared with rats in the control group, the plasma level of H(2)S decreased by 36% in rats of hypoxic group. The apoptotic rate per area in VSMCs detected with TUNEL was significantly decreased by 52.9% in rats of hypoxic group. The expressing integral score of Bcl-2 of VSMCs was increased by 123.9% while Fas protein expression of VSMCs was decreased by 45% and caspase-3 protein expression of VSMCs was not significantly changed in rats of hypoxia group. But compared with rats in the hypoxia group, the plasma level of H(2)S increased by 65% in rats of hypoxia+NaHS group. The apoptotic rate in VSMCs of TUNEL was significantly increased by 62.5% in rats of hypoxia+NaHS group. The Bcl-2 protein expression of VSMCs was decreased by 36.4% in rats of hypoxia+NaHS group. The expressing integral scores of Fas and caspase-3 were significantly higher in rats of hypoxia+NaHS group than in those of hypoxia group.Hypoxia decreased the pulmonary artery smooth muscle cell apoptosis. H(2)S inhibited Bcl-2 protein expression of VSMCs and activated Fas and caspase-3 protein expressions of VSMCs, and therefore promoted the pulmonary artery smooth muscle cell apoptosis.

To investigate the interaction between nitric (NO) / nitric oxygenase (NOS) and hydrogen sulfide (H(2)S)/ cystathionine-gamma-lyase (CSE) system in the pathogenesis of hypoxic pulmonary hypertension.25 rats were randomly divided into four groups: hypoxic group (n=7 ), hypoxic + L-NAME group (n=6 ), hypoxic + PPG group (n=6) and control group (n=6 ). After 21 days, pulmonary artery mean pressure (mPAP) of each rat was evaluated, and the plasma concentration of H(2)S and NO was measured. Meanwhile, the activities of CSE in pulmonary tissue in hypoxic, hypoxic + L-NAME and control groups were detected, respectively, and expressions of NOS in pulmonary arteries in hypoxic, hypoxic + PPG and control groups were also detected by immunohistochemistry technique.mPAP was significantly increased in hypoxic rats as compared with normal controls. Meanwhile, compared with controls, the production of NO and H(2)S in plasma, the activity of CSE in pulmonary tissue and expression of NOS in pulmonary arteries were markedly decreased in hypoxic rats. However, mPAP was significantly increased in hyopxic + L-NAME group as compared with hypoxic groups, and at the same time, the plasma concentration of NO was markedly decreased. However, the plasma concentration of H(2)S and the activity of CSE in pulmonary tissue in hyopxic+L-NAME group were increased significantly as compared with those of hypoxic group. PPG also worsened pulmonary hypertension of hypoxic rats, however,it increased endogenous production of NO and the expression of NOS of pulmonary arteries obviously.There is a negative feed back effect between NO/NOS system and H(2)S/CSE system in development of hypoxic pulmonary hypertension. They might interact with each other and therefore play an important regulating role in hypoxic pulmonary hypertension.

To investigate the effect of liposome-carried metallothionein (lipo-MT) on secondary ischemia-reperfusion injury in the rat island flap.An abdominal island flap was created in the Wistar rat. The animals were divided into four groups: the sham group, the secondary ischemia-reperfusion group, the group treated with blank liposome and the group treated with lipo-MT. The malondialdehyde (MDA) content, the myeloperoxidase (MPO) activity was assayed immediately, at 30 minutes and 7 days after the secondary venous ischemia-reperfusion. The level of endothelin (ET) and lactic dehydrogenase (LDH) of the rat plasma was measured at 30 minutes after secondary venous ischemia-reperfusion. The content of MT of the flap was assayed by Cd-hemoglobin saturation method at 7 days after the operation.The treatment of lipo-MT significantly decreased the content of MDA, MPO of the flap, decreased the activity of ET, LDH of the rat palsma, increased the content of MT of the flap and improved the flap viability.Lipo-MT can improve flap survival by reducing ischemia-reperfusion injury.

To study the alterations of myocardial taurine transport function, taurine transporter (TAUT), and cysteine sulfinate decarboxylase (CSD) mRNA as well as effect of exogenous taurine in rats with isoproterenol (ISO)-induced cardiomegaly.[3H]-Taurine uptake and release on myocardium were determined. Binding sites of [3H]-taurine for myocardial sarcolemma were measured. TAUT and CSD mRNA levels were assayed using competitive quantitative reverse transcriptase polymerase chain reaction (RT-PCR).ISO group as compared with control group, myocardial taurine uptake markedly reduced, taurine release obviously increased; Bmax value of [3H]-taurine binding on cardiac sarcolemma reduced by 42% (P0.05); TAUT and CSD mRNA levels decreased by 40% and 38% (P0.05), respectively. ISO+taurine group as compared with ISO-treated group, the amounts of taurine uptake and TAUT mRNA returned to normal; taurine release reduced; Bmax increased by 92% (P0.01), and CSD mRNA content augmented by 23% (P0.05). There were no statistical differences of Kd values among the four groups (P0.05).The data indicate that the failure to generate sufficient TAUT on myocardial sarcolemma may be the fundamental abnormality in ISO-induced cardiac injury. The mechanism by which administration of taurine considerably improves ISO-induced cardiac damage is probably to increase the expression of TAUT gene and recover taurine transport function.