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The blood‐retinal barrier (BRB), homeostasis, neuronal integrity, and metabolic processes are all directly influenced by Müller cells, the most important retinal glial cells. We isolated primary Müller cells from Sprague–Dawley (SD) neonatal rats and treated them with glucose at varying doses. CCK‐8 was used to quantify cellular viability, and a TUNEL assay was performed to detect cell apoptosis. ELISA, immunofluorescence, and western blotting were used to assess cAMP/PKA/CREB signaling, Kir4.1, AQP4, GFAP, and VEGF levels, respectively. H&E staining was used to examine histopathological alterations in diabetic retinopathy (DR)‐affected retinal tissue in rats. As glucose concentration increases, gliosis of Müller cells became apparent, as evidenced by a decline in cell activity, an increase in apoptosis, downregulation of Kir4.1 level, and overexpression of GFAP, AQP4, and VEGF. Treatments with low, intermediate, and high glucose levels led to aberrant activation of cAMP/PKA/CREB signaling. Interestingly, blocking cAMP and PKA reduced high glucose‐induced Müller cell damage and gliosis by a significant amount. Further in vivo results suggested that cAMP or PKA inhibition significantly improved edema, bleeding, and retinal disorders. Our findings showed that high glucose exacerbated Müller cell damage and gliosis via a mechanism involving cAMP/PKA/CREB signaling. [ABSTRACT FROM AUTHOR]

Background: Anti-angiogenesis treatments are the most commonly used treatments for the vision loss caused by exudative age-related macular degeneration (AMD), in which the anti-vascular endothelial growth factor (VEGF) drugs with ranibizumab and bevacizumab are current standard treatments. However, the outcome of anti-VEGF therapeutics is not uniform in all patients.Methods: We performed a literature-based meta-analysis including, five published studies relevant to HTRA1 and response to anti-VEGF treatment (bevacizumab or ranibizumab). Summary odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using fixed- and random-effects models. Sensitivity analysis and meta-regression were also performed. Q-statistic test and Egger's test was used to evaluate heterogeneity and publication bias respectively.Results: Overall, no association between the rs11200638 polymorphism in HTRA1 gene and the anti-VEGF treatment response was found in the genotype GG versus AA (OR = 1.06; 95% CI: 0.77 to 1.48; P = 0.98), genotype GA versus AA (OR = 1.11; 95% CI: 0.83 to 1.47; P = 0.93), genotype GG + GA versus AA (OR = 1.22; 95% CI: 0.94 to 1.57; P = 0.09), and allele G versus A (OR = 0.92; 95% CI: 0.78 to 1.08; P = 0.14). In the subgroup analysis by ethnicity Caucasian population, and a significant association was still not observed in all genetic models. Sensitivity analysis indicated the robustness of our findings, and no publication bias was observed in our meta-analysis.Conclusions: This study shows that there was no association between the polymorphism rs11200638 in HTRA1 gene and response to anti-VEGF treatment of exudative AMD. However, more studies are needed to further prove the conclusion of present study, especially well-designed and high quality randomised controlled trials or intervention studies. [ABSTRACT FROM AUTHOR]

Telmisartan with partial activation of peroxisome proliferator-activated receptor γ ( PPARγ) powerfully reduces blood pressure, improves endothelial function and lipid metabolism. Hepatocyte growth factor/mesenchymal-epithelial transition factor ( HGF/ Met) system in the local vasculature plays a pivotal role in maintaining normal endothelial function. This study is aimed to evaluate whether telmisartan directly prevents angiotensin II ( Ang II)-induced endothelial dysfunction ( ED) via activating HGF/ Met system and/or PPARγ pathway. The isolated aortic rings of rabbits were incubated with Ang II (0.01-1 μ m), telmisartan (0.1-10 μ m), SU11274 (5 μ m) as a specific Met inhibitor, GW9662 (10 μ m) as a PPARγ antagonist alone or a combination for 6 h. Ang II obviously inhibited the m RNA and protein expression of HGF, Met and PPARγ, and the accumulative concentration-relaxation of the aortic rings to acetylcholine, among which the inhibitory effect of 1 μ m Ang II was most significant. By contrast, telmisartan significantly increased the m RNA and protein expression of HGF, Met, and PPARγ, thus preventing Ang II-induced ED in a dose-dependent pattern. However, SU11274, GW9662 or a combination of both partially abolished the protective effects derived from telmisartan, with the effect of SU11274 exceeding that of GW9662. These results demonstrate that Ang II-induced ED in rabbit aortic rings in vitro can be prevented by telmisartan through selective PPARγ-modulating pathway. Moreover, this study indicates for the first time that activating HGF/ Met system in the local vasculature is involved in the protective mechanism of telmisartan. [ABSTRACT FROM AUTHOR]

Laparoscopic surgery has gradually replaced most of the traditional surgeries because of its advantages, such as good curative effect, rapid postoperative recovery, leaving almost no abdominal scar. It has become one of the minimal invasive surgeries which are most widely used and have promising developing prospect in gynecological operations. In recent years, it has become a concern that whether the various types of surgical manipulations in gynecological laparoscopic procedure can lead to the decrease of ovarian reserve function or even premature ovarian failure. Correct understanding and use of laparoscopic energy device can help improve a healthy development of laparoscopy. This paper focuses on different aspects, including the anatomy of ovary, the detection of ovarian reserve function, the impacts of laparoscopic surgery on the ovarian function, the protection measures for the ovarian function during the laparoscopic surgery and so on. It has been concluded that grasping the correct operation indication, choosing the appropriate operative procedures, and mastering skilled surgical techniques have important significance for protecting the ovarian function. [ABSTRACT FROM AUTHOR]

Vascular endothelial dysfunction ( VED) and inflammation contribute to the initiation and progression of atherosclerosis. Melatonin ( MLT) normalizes lipid profile, improves endothelial function, and possesses anti-inflammatory properties. However, the precise mechanisms are still unclear. This study investigated whether MLT could ameliorate VED, inflammation, and atherosclerosis by suppressing the Toll-like receptor 4 ( TLR4)/nuclear factor kappa B ( NF-κB) system in high-fat-fed rabbits. Rabbits were randomly divided into three groups that received a standard diet (control group), high-cholesterol diet (atherosclerosis group), or high-cholesterol diet plus 10 mg/kg/day MLT ( MLT group) for 12 wk. After treatment, high-fat diet significantly increased serum lipid and inflammatory markers in rabbits in atherosclerosis group compared with that in control group. In addition, high-fat diet also induced VED and typical atherosclerotic plaque formation and increased intima/media thickness ratio, which were significantly improved by MLT therapy as demonstrated in MLT group. Histological and immunoblot analysis further showed that high-fat diet enhanced the expressions of TLR4, myeloid differentiation primary response protein (MyD88), and NF-κB p65, but decreased inhibitor of NF-κB (IκB) expression. By contrast, MLT therapy decreased the expressions of TLR4, MyD88, and NF-κB p65 and increased IκB expression. This study has demonstrated that MLT ameliorates lipid metabolism, VED, and inflammation and inhibits the progression of atherosclerosis in high-fat-fed rabbits. Moreover, our study indicates for the first time that suppression of the TLR4/ NF-κB system in local vasculature with atherosclerotic damage is important for the protective effects of MLT. [ABSTRACT FROM AUTHOR]

Panax notoginseng is used as a therapeutic agent to stop haemorrhages and a tonic to promote health in Chinese medicine. Currently saponins of P. notoginseng (PNS) are especially given attentions for their hemorheological properties. The pharmacokinetic profiles of the main PNS are still not accurately investigated. Therefore, our preliminary aim is to elucidate the pharmacokinetic features of ginsenoside Rb1 (Rb1) and ginsenoside Rg1 (Rg1), two of the main PNS in rats. Firstly, quantitive analysis of Rb1 and Rg1 in saponins of P. notoginseng was studied and the most suitable assay method by HPLC for blood sample were established. Then Rb1 and Rg1 in the same serum were determined after administering PNS to rats. The decline of Rb1 in serum could be described by a two-compartment model. The half-life of α phase was 23.40 min and that of β phase was 17.96 h. Rb1 was absorbed from the digestive tract and the bioavailability via P.O. was 4.35%. The pharmacokinetics of Rg1 in rats also could be described by a two-compartment model. The half-lives of Rg1 were 24.23 min for α phase and 14.13 h for β phase. Rg1 could be absorbed in the digestive tract and the oral bioavailability was 18.40%. Both of the low oral bioavailability of Rb1 and rapid reduction of Rg1 in blood indicated that formula modification is necessary. [Copyright &y& Elsevier]

Objectives: To observe the effect of electroacupuncture (EA) of scalp acupoint (Dingnieqian-xiexian, MS6) on expression of retinoid-related orphan receptor γT (ROR γ t), interleukin (IL)-17A, IL-10, transfor-ming growth factor-β1 (TGF-β1), IL-6, IL-21, and IL-17A + Thelper cells(Th) 17 and forkhead transcription factor P3 (FOXP3) + regulatory T cells (Treg) differentiation of ischemic cortex in ischemic stroke rats, so as to explore its molecular mechanisms underlying relief of inflammatory injury of ischemic stroke., Methods: A total of 120 male SD rats were randomly assigned to sham operation, model, EA, inhibitor, agonist and EA+agonist groups, with 15 rats in each group. The ischemic stroke model was established by occlusion of the left middle cerebral artery according to Longa's methods. For rats of the EA group and EA+agonist group, EA (2 Hz/100 Hz, 1 mA) was applied to bilateral MS6 for 30 min, once daily for 7 days. Rats of the inhibitor group received intraperitoneal injection of solution of SR1001 (RORγt inhibitor) (2.5 mg/mL, 10 mg/kg), once daily for 7 days. Rats of the agonist and EA+agonist groups received intraperitoneal injection of solution of SR1078 (RORγt agonist) (5 mg/mL, 5 mg/kg) before EA, once daily for 7 days. Rats of the sham operation and model groups were grabbed and fixed in the same way with the other groups. The Zea-longa's score, modified neurological severity score (mNSS) and the neurobehavioral score were assessed before and after the intervention. At the end of experiments, the ischemic cortex tissue was collected. The 2, 3, 5-Triphenyltetrazolium chloride (TTC) staining was used to detect the volume of cerebral infarction. The expression of RORγt mRNA was detected by real-time quantitative PCR；the protein expression levels of RORγt, IL-17A, IL-10 and TGF-β1 were detected by Western blot；the immunoactivity of IL-6 and IL-21 were detected by immunohistochemistry；the fluorescence areas of IL-17A + Th17 and FOXP3 + Treg cells were measured by immunofluorescence and their ratio was calculated in the tissue of ischemic cortex., Results: Relevant to the sham operation group, the model group had a significant increase in the Zea-Longa's score, mNSS score, neurobehavioral score, cerebral infarct volume, expression levels of RORγt mRNA and protein, IL-17A protein, IL-6 and IL-21 immunoactivity, IL-17A + Th17 immunofluorescence intensity, and the ratio of IL-17A + Th17/FOXP3 + Treg ( P <0.01), and an obvious decrease in the expression levels of TGF-β1 and IL-10 proteins and FOXP3 + Treg immunofluorescence intensity ( P <0.01). In contrast to the model group, both EA and inhibitor groups had a significant decrease in the Zea-Longa's score, mNSS score, neurobehavioral score, cerebral infarct volume, expression levels of RORγt mRNA and protein, IL-17A protein, IL-6 and IL-21 immunoactivity, IL-17A + Th17 immunofluorescence intensity, and the ratio of IL-17A + Th17/FOXP3 + Treg ( P <0.01, P <0.05), and a marked increase in the expression levels of TGF-β1 and IL-10 proteins and FOXP3 + Treg immunofluorescence intensity ( P <0.05, P <0.01), while the above indicators of the agonist group were all reversed ( P <0.01, P <0.05). Comparison between the agonist and EA+agonist groups showed that the Zea-Longa's score, mNSS score, neurobehavioral score, cerebral infarct volume, expression levels of RORγt mRNA and protein, IL-17A protein, IL-6 and IL-21 immunoactivity, IL-17A + Th17 immunofluorescence intensity, and the ratio of IL-17A + Th17/FOXP3 + Treg were significantly lower ( P <0.01, P <0.05), and the expression of TGF-β1 and IL-10 proteins and FOXP3 + Treg immunofluorescence intensity were obviously higher ( P <0.01, P <0.05) in the EA+agonist group than in the agonist group, suggesting that EA intervention can effectively weaken the effects of RORγt agonist., Conclusions: EA of scalp acupoint MS6 can effectively improve the neurological function, behavior reaction and reduce cerebral infarct volume in ischemic stroke rats, which may be associated with its functions in down-regulating the expression of RORγt and promoting the balance of IL-17A + Th17/FOXP3 + Treg to alleviate inflammatory injury after ischemic stroke.

This study aimed to investigate the transport characteristics of aripiprazole. A human intestinal epithelial cell model Caco-2 cell in vitro cultured had been applied to study the transport of aripiprazole. The effects of time, concentration of donor solutions, pH, temperature and P-glycoprotein inhibitor on the transport of aripiprazole were investigated. The determination of aripiprazole was performed by HPLC. It is concluded that aripiprazole is transported through the intestinal mucosa via a passive diffusion mechanism primarily, coexisting with a carrier-mediated transport. The transport of aripiprazole is positively correlated to transport time, pH, and temperature. Papp increased with donor concentrations up to 10 microg x mL(-1), and then decreased for higher concentrations. The P-glycoprotein inhibitor cyclosporine A significantly enhanced the transport amount of aripiprazole.

Poloxamers are found to be an efficient adjuvant with multiple effects and are applied generally in pharmaceutical field. In recent years, it is investigated that poloxamers can increase the permeability of a broad spectrum of drugs through blood-brain barrier (BBB) by means of manifold mechanisms included: (1) inhibiting P-glycoprotein and multidrug-resistance associated protein efflux systems on BBB; (2) adsorbing different apolipoproteins in plasma on the surface of poloxamer-coated nanoparticles, which could interact with BBB through different receptors and mechanisms; (3) connecting to specific ligands and monoclonal antibodies to cross the BBB via specific endogenous transporters localized within the brain capillary endothelium. Significant roles of poloxamer in drug transport across BBB are considered in this review which provides for important guidance to the design of brain-targeted drug delivery system.

Objective: To purify caffeic acid tetramer (CAT) with macroporous resin on the basis of its fundamental physicochemical stability research., Method: The changes of CAT content were compared by HPLC method before and after the purification process, or while other conditions were altered., Result: LK001 was the best one among 7 kinds of macroporous resin in regard of purifying ability. The optimum absorbing technology was the solution concentration at 10 g x L(-1), pH at 4.5, and the flow rate at 3 BV x h(-1). The best eluting technology was 45% ethanol as eluting agent, pH at 5.0, eluting volume at 50 mL after applying super-purified water and 20% ethanol. The yield of product was 3. 6 percent, and the active compound CAT was 58 percent in the product., Conclusion: Macroporous resin LK001 is effective in enriching CAT from the crude extracts, thus this method of purification is advisable.

Drug delivery system (DDS) is a novel approach to overcome multidrug resistance (MDR) in tumors nowadays. This work was designed to investigate a new micellar delivery system for in vitro reversal of resistant ovarian tumor cells, based on a nonionic triblock copolymer Pluronic P105 and paclitaxel (PTX). The PTX-loaded polymeric micelles (P105/PTX) were prepared by thin film-hydration methods. Based on the results of single factor experiments, the P105/PTX micelle formulation was optimized by employing the central composite design-response surface methodology. The physico-chemical properties of the P105/PTX micelles were characterized, including micelle size, drug loading coefficient, in vitro release behavior, etc. The cytotoxicity of the P105/PTX micelles was assessed against human ovarian tumor cell line, SKOV-3/PTX, by a standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl (MTT) assay. In order to understand the possible mechanism of Pluronic effects in resistant tumor cells, cellular uptake study of micellar PTX or Rhodamine-123 (R-123) was also carried out. The results showed that the micelle size was about 24 nm with drug loading coefficient of 1.1% and PTX concentration of 700 microg x mL(-1). The cumulative release amount of PTX from the P105/PTX micelles was only 45.4% in 6 h (P < 0.05) and 79.6% in 24 h, whereas Taxol injection in 6 h released 95.2% PTX. The IC50 values of the P105/PTX micelles and Taxol injection against SKOV-3/PTX were 1.14 and 5.11 microg x mL(-1), and resistance reversion index (RRI) was 9.65 and 2.15, respectively. The micellar PTX or R-123 exhibited a significant increase in cellular uptake in resistant SKOV-3/PTX cells compared with free PTX or R-123. These results indicated that PTX could effectively be solubilized by Pluronic P105 block copolymers via thin film-hydration process and formulation optimization, producing nano-scale polymeric micelles with sustained release property in vitro. The P105/PTX micelles were effectively able to reverse resistance to PTX in SKOV-3/PTX tumor cells compared with Taxol injection or free PTX solution, and the enhanced cytotoxicity in the resistant SKOV-3/PTX cell was related to the improved cellular uptake of PTX by Pluronic P105 copolymers.

Objective: To explore the influence of carbon dioxide pneumoperitoneum-laparoscopic surgery on tumor cell seeding and metastases in endometrial cancer., Methods: Twenty patients with endometrial cancer who underwent laparoscopic surgery and 10 patients with endometrial cancer who underwent laparotomic surgery were enrolled. Each patient was in preoperative clinical StageIand the uterus size in each patient was less than 12 weeks of pregnancy. Carbon dioxide pneumoperitoneum was established and maintained with CO2 insufflation at 4 approximately 6 L/min and intraperitoneal pressure of 13 mmHg with an automatic pneumoperitoneum machine. Cytologic examination of peritoneal fluid(at the beginning and end of the operation), CO2 filtrated gas and the lavage fluid of instruments during the laparoscopic surgery were performed. The protein expressions of E-cadherin,beta-catenin,P-selectin,matrix metalloproteinase-2(MMP-2),vascular endothelial growth factor (VEGF),and CD44v6 in tumor tissues before and after the operation were detected by DAKO Envision., Results: There were no case of positive washing cytology in the peritoneal fluid,CO2 filtrated gas, and the lavage fluid of instruments during the laparoscopic surgery. The expressions of E-cadherin and beta-catenin proteins were obviously abnormal in endometrial cancer. The abnormal expressions of E-cadherin and beta-catenin protein between the pre- and post-operations were not significantly different in both the laparoscopic group and the laparotomic group(P>0.05).The changes of abnormal expressions of E-cadherin and beta-catenin protein were no statistical difference between the two groups(P>0.05). The positive protein expressions of P-selectin,MMP-2,VEGF,and CD44v6 were not significantly different between the pre- and post-operations both in the laparoscopic group and the laparotomic group(P>0.05),and there was also no significant difference between the laparoscopic group and the laparotomic group(P>0.05).The follow-up period in the laparoscopic group was 7 approximately 19 (14.25+/-3.65) months and 7 approximately 19 (13.10+/-4.23) months in the laparotomic group. One patient got infection in the urinary system in the laparoscopic group and one patient had lower extremity venous thrombosis in the laparoscopic group.No recurrence was detected in both groups., Conclusion: Laparoscopic surgery for endometrial cancer has no effect on protein expressions of E-cadherin,beta-catenin,P-selectin,MMP-2,VEGF,and CD44v6 in tumor tissues. No evidence has been found that CO2 pneumoperitoneum-laparoscopic surgery may favor endometrial cancer cell seeding and metastases.

To compare the characteristics of absorption and pharmacokinetic behavior of ginsenoside Rg1 (Rg1) with ginsenoside Rb1 (Rb1) of panax notoginseng saponins (PNS), bile excretion of both Rg1 and Rb1 were studied after i.v. and i.g. of PNS solution. Plasma protein binding ratios were studied using equilibrium dialysis method, and referred to pharmacokinetic parameters. It shows that (61.48 +/- 18.30)% dose of Rg1 and (3.94 +/- 1.49)% dose of Rb1 were separately excreted into bile 10 hours after i.v. administration (PNS 50 mg x mL(-1)), and (0.91 +/- 0.51)% dose of Rg1 and (0.055 +/- 0.02)% dose of Rb1 were excreted into bile 12 hours after i.g. administration (PNS 1 500 mg x mL(-1)). Plasma protein binding degrees of Rg1 and Rb1 were 6.56% - 12.74% and 80.1% - 89.69%, respectively. Stomach, intestinal and hepatic throughput efficiency (F(S), F1 and F(H)) for Rg1 were 49.85%, 13.05%, 50.56%, respectively, and 25.82%, 4.18%, 65.77% for Rb1. Therefore, poor intestinal absorption is a primary reason for the low bioavailability of both Rg1 and Rb1. Rg1 possesses relatively high bile excretion and low plasma protein binding rate, in contrast, Rb1 possesses low bile excretion and high plasma protein binding rate. Membrane permeability and elimination rate of Rb1 were lower than that of Rg1, meanwhile, longer MRT and bigger AUC could be found for Rb1.

Water in oil (W/O) microemulsion formulation was developed to enhance intestinal absorption of ginsenoside Rb1 (Rb1) of panax notoginseng (PNS). Effects of W/O microemulsions on pharmacokinetics after intraduodenal administration, membrane fluidity and membrane transport of Rb, were studied in rats, liposomes and parallel artificial membrane permeability assay (PAMPA), respectively. Soybean phospholipids/ethanol (SP/EtOH) was selected as surfactant/cosurfactant, together with PNS 400 mg x mL(-1) solution and various kinds of oils, to prepare 11 W/O microemulsions. Most of the microemulsions can enhance Rb1 intestinal absorption significantly. Besides surfactant/cosurfactant, oil also had an effect on the enhanced absorption and the order of enhancement was as follows: glyceryl laurate approximately = isopropyl myristate > isopropyl palmitate > 2-ethylhexanol palmitate. The effection of absorption enhancement by the long chain glyceride ( > C14) is lower than that by the medium chain glyceride (C8 - C14). Most of W/O microemulsions were found to enhance the membrane fluidity of liposomes to different extents. In PAMPA analysis, efficient permeability coefficient (Pe) of diluted-microemulsion (D-ME) is mostly higher than that of PNS solution, which indicated the components of microemulision can facilitate the membrane permeability of the drug. Meanwhile, linearity correlation between Pe and ratio of relative bioavailability (Fr) was acquired for undiluted microemulison (ME). Therefore, W/O microemulsions can enhance intestinal absorption of Rbr, and this effect may be attiributed to its enhancement on membrane fluidity to a certain degree. PAMPA analysis could be brought into not only the investigation of membrane transport of crude drug, but also conditioned preformulation research (e.g. absorption enhancer etc.).

Aim: To study the mechanism of absorption after oral administration of panaxnotoginseng saponins (PNS)., Methods: Caco-2 cells and rat models were applied to evaluate the degradation of both ginsenoside Rb1 (Rb1) and ginsenoside Rg1 (Rg1) in PNS in gastrointestinal lumen, and the transport mechanism of PNS across the intestinal mucosa, and the barrier function of stomach, intestine and liver involved in absorption process., Results: Rb1 and Rg1 proved to be readily eliminated in stomach, but stable in relatively neutral circumstance. Both Rb1 and Rg1 in PNS, especially for Rb1, degraded significantly in the contents of large intestine. However, both of them kept mainly intact in the contents of small intestine. Uptake of both Rb1 and Rg1 by Caco-2 cell monolayer was inhibited at low temperature, but not by cyclosporine A, and the change in the apical pH showed no pronounced effect. Uptake and transport were non-saturable and increased linearly with increasing of concentrations of Rb1 and Rg1 over the range of concentration tested, which indicated a passive transport. There was no significant difference of absorption characteristic between monomer (Rb1 and Rg1) and mixture (PNS). Uptake amount of Rg1 [(1.07 +/- 0.16) microg x mg(-1) (protein)] (C0 = 1 mg x mL(-1)) in Caco-2 cells was a little higher than that of Rb1 [(0.77 +/- 0.03) microg x mg(-1) (protein)] (C0 = 1 mg x mL(-1)). Meanwhile, apparent permeability coefficient of (5.9 +/- 1.0) x 10(-8) cm x s(-1) (C0 = 1 mg x mL(-1)) for Rb1 and (2.59 +/- 0.17) x 10(-7) cm x s(-1) (C0 = 1 mg x mL(-1)) for Rg1 from apical compartment to basolateral compartment predicted an incompletely absorption. Transports of both Rb1 and Rg1 were not influenced by cyclosporine A. The investigation on the pharmacokinetic behavior of Rb1 and Rg1 after different routes of administration to rats showed that the absolute bioavailability after peroral (po), intraduodenal (id), and portal venous (pv) administration is 0.71% , 2.75% and 65.77% respectively for Rb1, and 3.29%, 6.60% and 50.56% respectively for Rg1., Conclusion: Transport across Caco-2 cell monolayer for PNS (include Rb1 and Rg1) is a simple passive diffusion process. No efflux transporters in Caco-2 cells and other components in PNS showed effects on it. The elimination in stomach, large intestine and liver contributed to the low bioavailability of PNS, but the low membrane permeability might be a more important factor dominating the extent of absorption.

Aim: To study the effect of negatively charged and positively charged self-microemulsifying systems (SMES) on the cellular tight junction complex was to be investigated at molecular cell level., Methods: Human intestinal epithelial Caco-2 cell model was established. Effect of formulations on the transepithelial electrical resistance (TEER) and permeability of the paracellular transport marker mannitol were measured to evaluate the cell integrity. Changes in subcellular localization of the tight junction protein zona occludens 1 (ZO-1) and cytoskeleton protein actin by immunofluorescence were also assessed after treatment of two SMESs in different dilutions., Results: The TEER of cell monolayers was not markedly affected by negatively charged SMES in different dilutions. The positively charged SMES could significantly decrease the TEER (P < 0.05) in three dilutions. The full recovery of TEER was found after the treatment of lower dilution for 2 h, then cultured for 48 h, while the recovery of TEER was 81.3% of control in 1 : 50 dilution. Two SMESs could enhance the apparent permeability coefficient of mannitol (2.9 - 64.6 folds), which depended on the dilution times. The immunofluorescent results indicated that the distribution of ZO-1 and actin were discrete in cell membrane after the treatment of formulation. Since the positively charged microemulsion could bind to the epithelial cell membrane by electrostatic interaction, the actin of the cells undergone some kind of stress stimulated by the higher concentration of microemulsion was more markedly affected than the negatively charged SMES. Effect of formulations on ZO-1 and actin relied on the dilution., Conclusion: SMES is able to enhance the paracellular transport marker mannitol. The mechanism of opening of tight junctions by SMES might be the change of distribution of ZO-1 and actin.