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Parkinson's disease is a common chronic neurodegenerative disease characterized by massive loss of dopaminergic neurons in the substantia nigra. Neuroinflammation has been shown to play an important role in the pathogenesis of neurodegenerative diseases such as Parkinson's disease. The role of immune tolerance in neuroinflammation and neurodegenerative diseases induced by peripheral factors is unclear.This study established a model of endotoxin tolerance to explore the protective effect of endotoxin tolerance on Parkinson-like changes induced by repeated peripheral injections of high-dose LPS, and to explore its inflammatory mechanism.In this study, mice were injected intraperitoneally with low dose (0.5 mg/kg) LPS for 4 days to induce endotoxin tolerance (ET). Then, high-dose (1 mg/kg) LPS was injected continuously intraperitoneally for 4 days to induce Parkinson-like changes. Cytokines were detected by enzyme-linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qRT-PCR). Activation of microglial cells was detected by protein expression of CD68 and ionized calcium binding adapter molecule 1(Iba-1) by Western blotting and immunofluorescence. Hematoxylin and eosin staining and expression of tyrosine hydroxylase (TH) and dopamine (DA) were used to assess dopaminergic neuronal injury. The open field test and muscle tension test were used to assess behavioral disorders.As expected, compared with non-ET animals, ET preconditioning significantly reduced the production of inflammatory cytokines in the substantia nigra, inhibited microglial activation, and alleviated the pathological changes of dopaminergic neurons.ET may be a promising intervention method for neurodegenerative diseases.HighlightsET was successfully induced by continuous low-dose intraperitoneal LPS injection in mice.ET pretreatment inhibited neuroinflammation in the SN induced by continuous peripheral high doses of LPS.ET pretreatment inhibited continuous peripheral high-dose LPS injection-induced microglial activation in the SN.ET pretreatment decreased LPS-induced functional impairment of dopaminergic neurons.ET reversed the morphological changes of dopaminergic neurons induced by peripheral high-dose LPS.ET pretreatment improved continuous peripheral high-dose LPS injection-induced behavioral impairment.

Objective To investigate the mechanisms of ATR-induced dopaminergic toxicity by microglia activation and the response of the Keap1/ Nrf2- ARE signaling pathway. Methods Wistar rats were treated with 50, 100 and 200 mg/kg ATR and BV-2 microglia cells were treated with 50, 100 μM ATR or 100 ng/mL LPS, respectively. Rats behavioral responses and histopathological changes were monitored. Immunohistochemical and immunofluorescence analysis detected Iba-1 and TH+ cells in rats. Keap1/Nrf2-ARE signaling-related proteins and inflammatory factors from BV-2 cells and rats were detected using ELISA, Western blot and Real-time PCR. Results After ATR treatment, the grip strength of Wistar rats was significantly decreased, and anxiety were clearly observed. TH+ neurons were reduced, however, the number of microglia cells and Iba-1 levels were increased clearly in SN. The release of ROS, TNF-α and IL-Iβ were increased, and levels of SOD and GSH-Px were significantly decreased. Keap1 mRNA expression and protein levels were decreased, while nuclear Nrf2 mRNA expression and protein levels were both increased in vivo and in vitro. Conclusion ATR could significantly activate microglia and exacerbate neurotoxicity and neuroinflammation, leading to accelerate dopaminergic neuron cell death by inhibiting Keap1/Nrf2-ARE signaling pathway.

Atrazine (ATR), a widely used herbicide, has been previously shown to damage spatial memory capability and the hippocampus of male rats during the development. It has also been indicated that physical exercise can improve learning and memory in both humans and animals, as a neuroprotective method. Our aim here was to investigate the effect of maternal ATR exposure during gestation and lactation on spatial learning and memory function and hippocampal morphology in offspring and to further evaluate the neuroprotective effect of swimming training and identify possible related learning and memory signaling pathways. Using Sprague-Dawley rats, we examined behavioral and molecular biology effects associated with maternal ATR exposure, as well as the effects of 8 or 28 days swimming training. Maternal exposure to ATR was found to impair spatial learning and memory by behavioral test, damage the hippocampal morphology, and reduce related genes and proteins expression of learning and memory in the hippocampus. The extended, 28 days, period of swimming training produced a greater amelioration of the adverse effects of ATR exposure than the shorter, 8 days, training period. Our results suggest that maternal ATR exposure may damage the spatial learning and memory of offspring male rats via PSD95/NR2B signaling pathway. The negative effect of ATR could be at least partially reversed by swimming training, pointing to a potential neuroprotective role of physical exercise in nervous system diseases accompanying by learning and memory deficit.

Atrazine (ATR) is a commonly used artificial synthetic herbicide world-wide, which has been implicated as a potential threat to human health. Previous studies have demonstrated that exposure to ATR affects hippocampus-dependent learning and memory in rodents, but the exact molecular mechanism remains to be elucidated. In this study, we investigated the effect of ATR on the hippocampus of postnatal day 35 male Sprague Dawley (SD) rats administered doses of either 10 or 100 mg/kg body weight (BW)/day of ATR for a period of 30 days. A Morris water maze (MWM) test revealed that ATR treatment impaired memory performance in the spatial probe test, especially amongst the high-dose group. Moreover, analysis by electron microscopy showed that hippocampal neuron ultrastructure in the dentate gyrus (DG) and cornu ammonis 1 (CA1) sub-regions was impaired in the ATR-treated groups. Finally, a downregulation in the mRNA and protein expression levels of members of the MEK/ERK/CREB pathway and downstream factors brain-derived neurotrophic factor (BDNF) and Zif268 was observed in hippocampal tissue following ATR treatment. Taken together, these results suggest that developmental exposure to ATR is able to induce functional and morphological lesions in the hippocampus of SD rats, and that the MEK/ERK/CREB signaling pathway may be involved in this process.

Atrazine (ATR) is a widely used herbicide that can induce the degeneration of dopaminergic (DAergic) neurons in the substantia nigra, resulting in a Parkinson's disease-like syndrome. Despite the high risk of environmental exposure, few studies have investigated strategies for the prevention of ATR neurotoxicity. Our previous studies demonstrated that ATR can impair mitochondrial function, leading to metabolic failure. Cells maintain mitochondrial quality through selective autophagic elimination, termed mitophagy. Soybean isoflavones (SI) possess multiple beneficial bioactivities, including preservation of mitochondria function, so it was hypothesized that SI can protect neurons against ATR toxicity by promoting mitophagy. Pretreatment of SH-SY5Y neurons with SI prevented ATR-induced metabolic failure and cytotoxicity as assessed by intracellular ATP, Na+-K+-ATPase activity, mitochondrial membrane potential, and cell viability assays. The neuroprotective efficacy of SI was superior to the major individual components genistein, daidzein, and glycitein. Ultrastructural analyses revealed that ATR induced mitochondrial damage, while SI promoted the sequestration of damaged mitochondria into autophagic vesicles. Soybean isoflavones also induced mitophagy as evidenced by upregulated expression of BNIP3/NIX, BEX2, and LC3-II, while co-treatment with the mitophagy inhibitor Mdivi-1 blocked SI-mediated neuroprotection and prevented SI from reversing ATR-induced BEX2 downregulation. Furthermore, BEX2 knockdown inhibited SI-induced activation of the BNIP3/NIX pathway, mitophagy, and neuroprotection. These findings suggest that SI protects against ATR-induced mitochondrial dysfunction and neurotoxicity by activating the BEX2/BNIP3/NIX pathway.

Atrazine (ATR) is a widely used herbicide with documented dopaminergic (DAergic) neurotoxicity that can lead to a Parkinson's disease (PD)-like motor syndrome. However, there have been few studies on preventative interventions. The aim of the present study was to investigate the neuroprotective efficacy of soybean isoflavones (SI) and associated molecular mechanisms in a rat model of ATR-induced DAergic toxicity. Male Sprague-Dawley rats (6 weeks old) received daily intraperitoneal injection of SI (10, 50, or 100 mg/kg) or vehicle followed 1 h later by oral gavage of ATR (50 mg/kg) for 45 consecutive days. Open field and grip-strength tests indicated no differences in motor function among treatment groups. Alternatively, histopathology revealed neuronal damage in the striatum of rats receiving vehicle plus ATR that was ameliorated by SI pretreatment. SI attenuate ATR-induced oxidative stress (indicated by MDA accumulation and GSH depletion) and inflammatory damage (as evidenced by TNF-α and IL-6 elevation) in the substantia nigra. ATR increased expression of the pro-apoptotic factor Bax and reduced expression levels of the DA synthesis enzyme tyrosine hydroxylase (TH) and the anti-apoptotic factor Bcl-2 in the substantia nigra and striatum. All of these effects were reversed by SI pretreatment, suggesting that SI can inhibit ATR-induced apoptosis of DAergic neurons. ATR also inhibited autophagy in the substantial nigra as evidenced by LC3-II and Beclin-1 downregulation and increased expression of p62, whereas SI pretreatment reversed these effects, indicating autophagy induction. Furthermore, ATR increased the expression of mTOR and reduced the expression of phosphorylated S6 (p-S6) and BEX2 in the substantia nigra. Collectively, these findings suggest that SI can prevent ATR-mediated degeneration of DAergic neurons by inducing autophagy through an mTOR-dependent signaling pathway.

BACKGROUND Simazine is a triazine herbicide used worldwide in both agricultural and non-agricultural fields that is frequently detected in surface water and groundwater. Due to its widespread use, an increasing amount of research has focused on the potentially serious environmental and health risks. MATERIAL AND METHODS We used Western blotting and real-time quantitative PCR to analyze the effects of simazine on dopamine neuronal development-related factors in MN9D dopaminergic cells. RESULTS The expression of tyrosine hydroxylase (TH) mRNA was significantly increased after treatment with 300 and 600 μmol L-1 simazine after 24 and 48 h. Levels of nuclear-related receptor 1 (Nurr1) mRNA after 24- and 48-h exposure were decreased with 50 μmol L-1 simazine, but increased with 600 μmol L-1 simazine. Significant increases in TH and Nurr1 protein were observed in all simazine-treated groups at 24 and 48 h. The expression of neurogenin 2 and LIM homeobox transcription factor 1 beta (Lmx1b) mRNA were significantly increased after exposure to 600 μmol L-1 simazine for 48 h, while the expression of wingless-type MMTV integration site family member 1 (Wnt1) mRNA was increased by all doses of simazine. CONCLUSIONS Simazine may have an impact on TH in MN9D cells through 2 mechanisms; one mechanism is through the Lmx1a/Ngn2 pathway, and the other mechanism is through the Lmx1b-pitx3/Wnt1-Nurr1 pathway. These 2 pathways likely do not operate in isolation, but rather together, during the cellular response to simazine exposure.

Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine; ATR) is widely used as an herbicide, and its accumulation in the environment is a health risk to humans; for instance, it has been shown to cause dopaminergic neurotoxicity. MicroRNAs (miRNAs) are endogenous small RNAs that regulate gene expression in diverse physiological contexts; however, the extent of their involvement in the development of Parkinson's disease (PD) is not known. In this study, we carried out miRNA profiling of peripheral blood and brain tissue in a rat model of PD in order to identify factors that mediate PD pathogenesis. The miRNAmiR-7 is known to cause the downregulation of α-synuclein (α-syn), which is linked to the neuropathology of PD. Here we found that miR-7 was upregulated in brain tissue but downregulated in peripheral blood of rats with ATR-induced PD. We also found that miR-7 regulates the expression of brain-derived neurotrophic factor (BDNF) through an auto regulatory mechanism. These findings indicate that miRNA-7 regulates the BDNF/α-syn axis in the early stages of PD and can serve as a biomarker or therapeutic target for disease treatment.

Atrazine (ATR) is a widely used herbicide that has been implicated as a neurotoxicant. Recent experimental evidence has implicated that ATR exposure also appears to have adverse effects on the hippocampus, which is a critical region for learning and memory. The aim of the present study was to investigate the effects of ATR toxicity on the hippocampus of developing rats. Postnatal day (PND) 28 male Sprague&ndash, Dawley (SD) rats received ATR by oral gavage at 10 or 100 mg/kg bodyweight (BW) for 30 consecutive days and were sacrificed at PND 90. Behavioral test results indicated that spatial learning and memory were affected by ATR treatment. Electron microscopy analysis showed that the ultrastructures of the hippocampus were altered in the ATR-treated groups, as compared to the control group. Additionally, ATR treatment impacted dopamine and D1 dopamine receptor (D1DR) contents through different mechanisms. Reduced mRNA and protein expression levels of factors involved in the cAMP-dependent signaling pathway were also detected. These results indicate that the developmental exposure of rats to ATR can damage the hippocampus and spatial memory, which might be related to the downregulation of expression levels of the D1DR and its downstream signaling pathway.

Atrazine (2-chloro-4-ethytlamino-6-isopropylamine-1,3,5-triazine, ATR) is widely used as a broad-spectrum herbicide. Animal studies have demonstrated that ATR exposure can cause cell death in dopaminergic neurons. The molecular mechanisms underlying ATR-induced neuronal cell death, however, are unknown. In this study, we investigated the autophagy and apoptosis induced by ATR in dopaminergic neurons in vivo. Wistar rats were administered with ATR at doses of 10, 50 and 100 mg/kg body weight by oral gavage for three months. In terms of histopathology, the expression of autophagy- and apoptosis-related genes as well as proteins related to the Beclin-1/B-cell lymphoma 2 (Bcl-2) autophagy and apoptosis pathways were examined in the rat nigrostriatal dopaminergic system. We observed degenerative micromorphology indicative of neuronal apoptosis and mitochondrial autophagy by electron microscopy in ATR-exposed rat striatum. The rat ventral mesencephalon in the ATR-exposed groups also showed increased expression of Beclin-1, LC3-II, Bax and Caspase-9, and decreased expression of tyrosine hydroxylase (TH), Bcl-xl and Bcl-2. These findings indicate that ATR may induce autophagy- and apoptosis-related changes in doparminergic neurons. Furthermore, this induction may be regulated by the Beclin-1 and Bcl-2 autophagy and apoptosis pathways, and this may help to better understand the mechanism underlying the neurotoxicity of ATR.

The objective of this study is to specify the effect of pressurized soy protein isolate (pSPI), upon the physical development, growth hormones and antioxidants functions of SD rats. The methodology depends on the selection of one hundred male SD rats, divided randomly into 5 groups. Each group consists of 20 rats. The groups will be defined as one blank control group, three groups with pSPI at low, medium and high doses and another control group with native soy protein isolates (nSPI). Low, medium and high doses are represented by 0.333 g/kg, 1.667 g/kg and 3.333 g/kg pSPI per weight, respectively. The native soy protein isolate is represented by 3.333 g/kg nSPI per weight. In every group, four animals will be taken out to collect the blood samples and analyze insulin like growth factor-I, growth hormone, thyroid stimulating hormone, thyroxine and triiodothyronin. The other SD rats will be subjected to feeding for 63 consecutive days. The body weight, the body length and food intake of each rat are measured. The total antioxidant capacity, superoxide dismutase (SOD), malondialdehyde and Glutathione Peroxidase in liver and serum of each rat will be analyzed. The results indicated that the groups with medium and high dose of pSPI result in an obvious increase in the body weight, body length and food utilization rate of SD rats. Also, pSPI has a great effect on the growth and antioxidants functions of SD rat.

Many studies have shown that the pollutant simazine (6-chloro-N,N′-diethyl-1,3,5-triazine-2,4-diamine), which has been overused, inhibits the proliferation of mammalian dopaminergic cells, and affects the developmental differentiation of mammalian dopaminergic neurons. However, few studies have shown the effects of simazine on dopaminergic metabolism in these cells. Therefore, we aim to examine the metabolic effects of simazine exposure in mouse dopaminergic progenitor neurons (MN9D) at different exposure times. The cells were treated with simazine at 0, 150, 300 and 600 µM for 12, 24 and 48 h, respectively. The content of dopamine in these cells was then examined using the enzyme-linked immunosorbent assay (ELISA) kit. Real-time quantitative polymerase chain reaction (PCR) and western blotting were performed to analyze the mRNA and protein expression of aromatic amino acid decarboxylase (AADC), tyrosine hydroxylase (DYT5b), dopamine transporter (DAT), monoamine vesicular transporter 2 (VMAT2), monoamine oxidase (MAO) and catechol-O-methyl transferase (COMT). The results showed that simazine influenced the metabolism of dopamine and led to a decrease in dopamine level in these cells which may eventually lead to neurological disorders of the dopaminergic system.

The herbicide, atrazine (ATR), is used worldwide and its contamination in the environment has resulted in documented human exposure. It has also been shown that ATR results in dopaminergic neurotoxicity, however, few studies have investigated the long-term effects of ATR following in utero exposure. Therefore, we evaluated the effects of ATR exposure in Sprague Dawley rats during gestational on the offspring dopaminergic system development. Pregnant dams were treated with oral ATR at 0, 25, 50 mg/kg/day from gestational day 0 to postnatal day 1. In this study, we examined the hypothesis that ATR could cross the placental barrier and have long-term adverse effects on the synthesis, degradation and reuptake of DA in the brain. For this purpose,we examine the concentration of levodopa (L-DA), dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) in stratum. The mRNA and protein expression of orphan nuclear hormone (Nurr1), tyrosine hydroxylase(TH), vesicular monoaminetransporter 2 (VMAT2), dopamine transporter (DAT), monoamine (MAO), and catechol-O-methyl transferase (COMT) in the midbrain were examined by fluorescence PCR and Western blot when the offspring reached six-month old or one year old .When measured 6 months post-treatment, the level of DA and expression of Nurr1, VMAT2, DAT and TH were reduced in the striatum and Substantia nigra, respectively.

A series of 2-(1-[2,6-bis[bis(4-fluorophenyl)methyl]-4-methylphenyl-imino}ethyl)-6-[1-(arylimino)ethyl]pyridylcobalt(II) chloride complexes (Co1-Co5) was synthesized and characterized by FT-IR spectroscopy and elemental analysis. The molecular structures of the representative cobalt complexes Co1 (R-1 = Me, R-2 = H), Co4 (R-1 = Me, R-2 = Me) and Co5 (R-1 = Et, R-2 = Me) were determined by single crystal X-ray diffraction, and revealed a pseudo-square-pyramidal geometry at cobalt. Upon activation with either MMAO or MAO, all cobalt complex pre-catalysts exhibited high activities [up to the range of 10(7) g of PE (mol of Co)(-1) h(-1)] toward ethylene polymerization. The influence of reaction parameters and the nature of the ligands were investigated in detail on the catalytic activities of the corresponding complexes and properties of the resultant polyethylene. The cobalt system revealed single-site behavior and produced polyethylene with narrow molecular distribution. Compared to the use of MAO, the use of MMAO produced polyethylene of higher molecular weight. (C) 2013 Elsevier B.V. All rights reserved.

The herbicide simazine is widely used in agricultural and non-agricultural fields. Studies have shown that simazine inhibits the proliferation of dopaminergic cells and affects the developmental differentiation of dopamine neurons. However, little is known about the effects of simazine on dopaminergic metabolism. Therefore, the present study examined the effects of simazine on Sprague‑Dawley (SD) rats from weaning to puberty (40 days exposure). Simazine was administered orally to SD rats at doses of 0, 12.5, 50 and 200 mg/kg body weight. The contents of dopamine (DA), levodopa, dihydroxy-phenyl-acetic acid and homovanillic acid in the striatum were then examined by high-performance liquid chromatography with a fluorescence detector. Quantitative polymerase chain reaction and western blotting were used to analyze the mRNA and protein expression of aromatic amino acid decarboxylase (AADC), tyrosine hydroxylase, orphan nuclear hormone (Nurr1), dopamine transporter (DAT), vesicular monoamine transporter 2 (VMAT2), monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT). The results indicated that simazine influenced the synthesis, transport and metabolism of DA and led to a reduction of DA levels in the striatum. One potential underlying mechanism is decreased levels of Nurr1, DAT and VMAT2 impacting upon the transport of DA; another is the decreased level of AADC and increased levels of MAO and COMT impacting upon the synthesis and metabolism of DA. These factors may eventually lead to neurological disorders of the dopaminergic system.

Dibromoacetic acid (DBA) is a haloacetic acid that is present in drinking water as a by-product of chlorinated disinfection. To evaluate its potential adverse health effects, the immunotoxicological effects of DBA on the thymus and spleen of BALB/c mice were investigated. Groups of mice (10 mice per group) were administered DBA at doses of 0, 5, 20, and 50 mg/kg body weight daily for 28 days via oral gavage. The mice orally administered DBA exhibited obvious immunotoxicity, as indicated by changes in the thymus and spleen. DBA induced a dose-dependent decrease and increase in thymus weight and spleen weight, respectively. The histological changes were cortical atrophy of the thymus, white pulp shrinkage of the spleen, and apoptosis of many splenic and thymic lymphocytes; these observations were confirmed by morphometric analysis of the electron microscope scans. Lymphocytes proliferation analysis indicated that the proliferative function of the splenic and thymic lymphocytes was altered after DBA exposure. Cell death via apoptosis was analyzed with an annexin-V/propidium iodide assay by flow cytometry, and we observed that the percentage of apoptosis increased in a dose-dependent manner after DBA treatment. In addition, DBA treatment altered the expression of a few apoptosis-related genes such as Fas, TRAF2, bcl-2, and bax in a dose-dependent manner. Western blot analysis revealed increased expression of the Fas and FasL proteins. In conclusion, DBA induces obvious immunotoxicity in the thymus and spleen, and immune-cell apoptosis mediated by the Fas/FasL pathway may be the potential mechanism underlying this immunotoxicity.

Atrazine (ATR) is a widely used herbicide, although it is potentially ecotoxic. Increasing evidence indicates that ATR plays a critical role in inducing physiological changes to the endocrine and reproductive systems, and further may affect the nigrostriatal dopaminergic system in the diencephalon, resulting in altered dopamine (DA) levels in the striatum, transport and storage-related protein abnormalities in the synaptic terminals, motor function deficits, and degeneration of DA neurons in the substantia nigra (SN). As the primary immunocytes in the central nervous system (CNS), microglial function to maintain the CNS microenvironment by preventing damage to healthy cells as well by regulating inflammatory responses. Several studies have demonstrated that microglial activation exerted an important effect on neuronal degeneration. In order to investigate dynamic changes of the microglial phenotype in the SN, rats received consecutive intraperitoneal injections of a vehicle or ATR at 25, 50, or 100 mg/kg body weight for a 14-day period and were then sacrificed at 1, 4, 7, or 14 days post-treatment, respectively. Here, we found that microglial activation by changes to phenotype emerged later in the low ATR exposure group than in the medium and high ATR exposure groups, and proliferating microglia were observed as well. Moreover, as two major inflammatory cytokines, expression of tumor necrosis factor α and interleukin-1β, emerged earlier post-ATR exposure, and a significant upregulation was observed in the medium and high ATR exposure groups. These results suggested that inflammatory reactions regulated by microglia occurred in a dose- and time-dependent manner, which may explain the severe DA neuron degeneration with the phagocytic phenotype of microglia in the SN that emerged earlier in the medium and high ATR exposure groups than in the low ATR exposure group. Taken together, our findings suggest that microglial activation might be involved in the dose- and time-dependent ATR-induced DA neuron degeneration in the SN.

High atrazine (2-chloro-4-ethytlamino-6-isopropylamine-1,3,5-triazine; ATR) contents in the environment threaten the health conditions of organisms. We examined the effects of ATR exposure on Sprague-Dawley rats during gestation and on the dopaminergic neurons of offspring during lactation. Pregnant dams were orally treated with 0 mg/kg/day to 50 mg/kg/day of ATR from gestational day 5 to postnatal day 22. Afterward, neither offspring nor dams received ATR. Dopamine (DA) content was examined in striatum samples by HPLC-FL; the mRNA expressions of tyrosine hydroxylase (TH), orphan nuclear hormone (Nurr1), dopamine transporter (DAT), and vesicular monoamine transporter 2 (VMAT2) in the ventral midbrain samples were examined by fluorescence PCR when the offspring reached one year of age. After the pregnant rats were exposed to ATR, the DA concentrations and mRNA levels of Nurr1 were decreased in their offspring. Decreased Nurr1 levels were also accompanied by changes in the mRNA levels of VMAT2, which controls the transport and reuptake of DA.

Sphingomyelin (SM) hydrolysis generates biologically active products regulating cell growth, differentiation and apoptosis. Dietary SM has been found to inhibit colonic tumorigenesis. Alkaline sphingomyelinase (alk-SMase) is the key enzyme responsible for sphingomyelin digestion in the gut. Whether or not dietary sphingomyelin affects alk-SMase expression was examined in a colon cancer animal model.Imprinting control region (ICR) mice were injected with 1,2-dimethylhydrazine (DMH) and then fed a diet with or without SM (0.5 g/kg in diet) for 22 weeks. The colonic tumorigenesis and alk-SMase activity were determined and alk-SMase expression was examined by Western blot and PCR.Dietary SM inhibited the tumorigenesis and increased the alk-SMase activity in the colon by 65%. The increased activity was associated with increased enzyme protein and mRNA expression. No changes of acid and neutral sphingomyelinase activities were found.Long-term supplementation with dietary sphingomyelin up-regulates colonic alk-SMase expression, which may contribute to the inhibitory effects of sphingomyelin against colonic carcinogenesis.

In this study, the release of mitochondrial proapoptotic intermembrane space proteins induced by exogenous C(2)-ceramide in human colon carcinoma (HT-29) cell line was investigated. HT-29 cells were treated with 12.5, 25 and 50 micromol/L C(2)-ceramide in vitro. Flow cytometer was used to detect the mitochondrial membrane potential (DeltaPhi(m)). Subcellular fractions were extracted by Mitochondrial/Cytosol Fractionation Kit after C(2)-ceramide treatment for 24 h. SDS-PAGE was used to determine the level of cytochrome c (Cyt c), high temperature requirement A2 (HtrA2) and second mitochondrial-derived activator of caspases (Smac) released from mitochondria, the expression of X-linked inhibitor of apoptosis protein (XIAP) and caspase-3 for 24 h. The results showed that DeltaPhi(m) began to decrease from 6 h after 25 and 50 micromol/L C(2)-ceramide treatment (P0.05) and cyclosporin A (CsA) could inhibit the collapse of DeltaPhi(m) through regulating mitochondrial membrane permeability transition pore. There was no effect of C(2)-ceramide on the expression of Cyt c, HtrA2 and Smac in the total levels. 12.5, 25 and 50 micromol/L C(2)-ceramide could induce Cyt c, HtrA2 and Smac to release from mitochondria to cytosol and down-regulate the expression of XIAP (P0.05). Also there was expression of cleaved caspase-3 with C(2)-ceramide treatment. After the treatment with caspase inhibitor, C(2)-ceramide still induced the release of Cyt c and HtrA2, but Smac did not. Therefore, C(2)-ceramide could induce apoptosis of HT-29 cells through the mitochondria pathway. The release of Cyt c, HtrA2 and Smac from mitochondria did not occur via the same mechanism, the release of Cyt c and HtrA2 was caspase-independent and the release of Smac was caspase-dependent.

An homopolymer and acrylonitrile/itaconic acid(AN/IA) bipolymer and AN/IA/MA(methacrylate) terpolymer were prepared in ethylene carbonate(EC) solution using azodiisobutyronitrile(AIBN) as initiator via the free radical solution polymerization method.Effect of reaction temperature on AN homopolymerization and effect of monomer concentration on the copolymerization were investigated.AN copolymer with a relative molecular mass of 4.5×105 and monomer conversion of 85% was synthesized.Relative molecular masses of AN homopolymer,AN/IA and AN/IA/MA copolymers were controlled through N-formylpiperidine(FP) and 1-dodecanethiol(DDT) as chain transfer agents.Influence of the mass fraction of chain transfer agents on the molecular mass and conversion rate of the copolymers were also studied.The results shows that a polymer with molecular mass of 1×105 and monomer conversion of 80% was obtained by 0.25% mass fraction of DDT as chain transfer agent.