Extract of Ginkgo biloba leaves attenuates neurotoxic damages in rats and SH-SY5Y cells exposed to a high level of fluoride.

BACKGROUND: Potential protection against the neurotoxic damages of high levels of fluoride on rats and SH-SY5Y cells by extract of Ginkgo biloba leaves, as well as underlying mechanisms, were examined. METHODS: The rats were divided randomly into 4 groups, i.e., control, treatment with the extract (100 mg/kg body weight, gavage once daily), treatment with fluoride (50 ppm F- in drinking water) and combined treatment with both; SH-SY5Y cells exposed to fluoride and fluoride in combination with the extract or 4-Amino-1,8-naphthalimide (4-ANI), an inhibitor of poly (ADP-ribose) polymerase-1 (PARP-1). Spatial learning and memory in the rats were assessed employing Morris water maze test; the contents of fluoride in brains and urine by fluoride ion-selective electrode; cytotoxicity of fluoride was by CCK-8 kit; the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and the content of malondialdehyde (MDA) by appropriate kits; the level of 8-hydroxydeoxyguanosine (8-OHdG) was by ELISA; the content of ROS and frequency of apoptosis by flow cytometry; the expressions of phospho-histone H2A.X(Ser139), PARP-1, poly (ADP-ribose) (PAR) and Sirtuin-1 (SIRT1) by Western blotting or immunofluorescence. RESULTS: The rats with prolong treatment of fluoride exhibited dental fluorosis, the increased contents of fluoride in brains and urine and the declined ability of learning and memory. In the hippocampus of the rats and SH-SY5Y cells exposed to fluoride, the levels of ROS, MDA, apoptosis, 8-OHdG and the protein expressions of histone H2A.X(Ser139), PARP-1 and PAR were all elevated; the activities of SOD and GSH-Px and the protein expression of SIRT1 reduced. Interestingly, the treatment of Ginkgo biloba extract attenuated these neurotoxic effects on rats and SH-SY5Y cells exposed to fluoride and the treatment of 4-ANI produced a neuroprotective effect against fluoride exposure. CONCLUSION: Ginkgo biloba extract attenuated neurotoxic damages induced by fluoride exposure to rats and SH-SY5Y cells and the underlying mechanism might involve the inhibition of PARP-1 and the promotion of SIRT1.

[Cloning and function analysis of promoter of DcCDPK8 from Dendrobium catenatum].

DcCDPK8 involved in abiotic stress such as low temperature and signal transduction of hormones ABA and MeJA,but the transcriptional regulation is still unclear. In order to study the core promoter region of DcCDPK8 gene in Dendrobium catenatum and explore its transcriptional regulation mechanism,the DcCDPK8 gene promoter sequence was cloned by PCR from D. catenatum. Promoter sequence function was studied by fusion of 5 'terminal deletion and GUS gene. The results showed that the promoter sequence of DcCDPK8 gene has a low-temperature responsive element( LTR) between~(-1) 749 bp and-614 bp,two MeJA responsive elements between~(-1) 749 bp and-230 bp,and one ABA responsive elements between-614 bp and-230 bp. Three 5'-end different deletion fragments were constructed to fuse the eukaryotic expression vectors p BI121 with GUS,which were transformed into tobacco leaves. The GUS activity under cold stress treatment was DcCDPK8-p1>DcCDPK8-p2>DcCDPK8-p3. GUS activity under exogenous ABA induction was DcCDPK8-p1>DcCDPK8-p2>DcCDPK8-p3,and GUS activity under exogenous MeJA induction was DcCDPK8-p1>DcCDPK8-p2>DcCDPK8-p3. It is speculated that the ABA response element( ARE) in the promoter sequences of DcCDPK8 is positive regulatory role in response to exogenous ABA,the MeJA cis-acting element plays a negative role in response to exogenous MeJA.

ClC-7/Ostm1 contribute to the ability of tea polyphenols to maintain bone homeostasis in C57BL/6 mice, protecting against fluorosis.

Epidemiological investigations indicate that certain ingredients in tea bricks can antagonize the adverse effects of fluoride. Tea polyphenols (TPs), the most bioactive ingredient in tea bricks, have been demonstrated to be potent bone-supporting agents. ClC­7 is known to be crucial for osteoclast (OC) bone resorption. Thus, in this study, we investigated the potential protective effects of TPs against fluorosis using a mouse model and explored the underlying mechanisms with particular focus on ClC­7. A total of 40, healthy, 3­week­old male C57BL/6 mice were randomly divided into 4 groups (n=10/group) by weight as follows: distilled water (control group), 100 mg/l fluoridated water (F group), water containing 10 g/l TPs (TP group) and water containing 100 mg/l fluoride and 10 g/l TPs (F + TP group). After 15 weeks, and after the mice were sacrificed, the long bones were removed and bone marrow-derived macrophages were cultured ex vivo in order to perform several experiments. OCs were identified and counted by tartrate­resistant acid phosphatase (TRAP) staining. The consumption of fluoride resulted in severe fluorosis and in an impaired OC function [impaired bone resorption, and a low mRNA expression of nuclear factor of activated T-cells 1 (NFATc1), ATPase H+ transporting V0 subunit D2 (ATP6v0d2) and osteopetrosis­associated transmembrane protein 1 (Ostm1)]. In the F + TP group, fluorosis was attenuated and OC function was restored, but not the high bone fluoride content. Compared with the F group, mature OCs in the F + TP group expressed higher mRNA levels of ClC­7 and Ostm1; the transportation and retaining of Cl­ was improved, as shown by the fluorescence intensity experiment. On the whole, our findings indicate that TPs mitigate fluorosis in C57BL/6 mice by regulating OC bone resorption. Fluoride inhibits OC resorption by inhibiting ClC­7 and Ostm1, whereas TPs attenuate this inhibitory effect of fluoride.

Status and determinants of health literacy among adolescents in Guangdong, China.

BACKGROUND: Previous studies for non-communicable disease cotrol, including cancer, have mostly relied on health literacy in adults. However, limited studies are available for adolescents. This study aimed to assess the status and determinants of health literacy in in-school adolescents in Guangdong, China. MATERIALS AND METHODS: A total of 3,821 students aged 13-25 years were selected by multi-stage cluster sampling. After the questionnaire of health literacy was answered, the total scores for health knowledge (18 questions), skills (5 questions) and behaviors (14 questions) were determined. The total scores for health literacy and each subscale were recoded into adequate and inadequate subgroups, and logistic regression models were used to identify factors associated with each outcome variable. RESULTS: The prevalence of adequate health literacy was 14.4%, and the prevalences for adequate knowledge, skills and behavior were 22.4%, 64.7% and 6.6%, respectively. Students coming from prestigious schools and having parents with higher education had higher odds of having adequate knowledge, skills and behaviors. Female students had higher odds of having adequate knowledge and behaviors. Students in grade 7-8 had higher odds of having adequate knowledge and skills. The health knowledge was positive associated with health skills (odds ratio [OR]=2.1, 95% confidence interval [CI] 1.7-2.5) and behaviors (OR=3.0, 95% CI 2.3-4.0), and health skills were positive associated with health behaviors (OR=2.6, 95% CI 1.8-3.8). CONCLUSIONS: Further efforts should be made to increase adolescents' health knowledge and behaviors, especially for low grade and male students in non-prestigious schools.

Inactivation of Akt by arsenic trioxide induces cell death via mitochondrial-mediated apoptotic signaling in SGC-7901 human gastric cancer cells.

Arsenic trioxide (As2O3) has been recognized as a potential chemotherapeutic agent, yet the details concerning its mechanism of action in solid cancers remain undetermined. The present study assessed the role of Akt in the cell death induced by As2O3. The MTT assay showed that As2O3 suppressed the proliferation of SGC-7901 cells in a dose- and time-dependent manner. Characteristic apoptotic changes were observed in the As2O3­treated cells by Hoechst 33342 staining, and FACS analysis showed that As2O3 caused dose-dependent apoptotic cell death. As2O3 activated caspase-3 and -9, and PARP cleavage in a dose-dependent manner. Compromised mitochondrial membrane potential and an increased protein level of Bax indicated involvement of mitochondia. As2O3 decreased the levels of p-Akt (Ser473), p-Akt (Thr308) and p-GSK-3ß (Ser9), suggesting that As2O3 inactivated Akt kinase. In addition, LY294002 (a PI3 kinase inhibitor) augmented the apoptosis induced by As2O3. These results demonstrated that inhibition of PI3K/Akt signaling was involved in As2O3-induced apoptosis of gastric cancer SGC-7901 cells.

[Effects of beta3-adrenergic receptor antagonist on myocardial UCP2 expression and energy metabolism in chronic heart failure rats].

OBJECTIVE: To observe the effects of beta3-adrenergic receptor(beta3-AR) antagonist on myocardial uncoupling protein 2 (UCP2) expression and energy metabolism in chronic heart failure rats. METHODS: Seven weight-matched normal adult rats (control group), 18 isoproterenol (ISO) induced heat failure (HR) rats (ISO group) and 21 ISO induced heart failure rats but received specific beta3-AR inhibitor SR59230A (ISO+ SR59230A group) for 6 weeks were included in this research. At the end of the study, echocardiography was performed, the ratio of left ventricular weight and body weight (LVW/BW) was calculated. The expression of beta3-AR ad UCP2 mRNA in myocardium were detected by reverse transcription-polymerase chain reaction (RT-PCR), the UCP2 protein in myocardium were detected by Western blot. The myocardial contents of creatine phosphate (PCr) and adenosine triphosphate (ATP) were measured by high performance liquid chromatography (HPLC). RESULTS: Compared with control group, the cardiac function was significantly reduced and myocardial beta3-AR mRNA significantly increased, UCP2 mRNA and protein were also significantly increased in ISO group, this change could be attenuated by the treatment with SR59230A, and the expression of myocardial UCP2 protein negatively correlated with the ratio of PCr/ATP. CONCLUSION: In the chronic stage of HF, the expression of UCP2 increases, which causes myocardial energy shortage, SR59230A improves myocardia energy efficiency and cardiac function by means of suppressing the expression of UCP2.

Associations between XRCC1 Arg399Gln, Arg194Trp, and Arg280His polymorphisms and risk of differentiated thyroid carcinoma: a meta-analysis.

BACKGROUND: Associations between Arg399Gln, Arg194Trp and Arg280His polymorphisms of the XRCC1 gene and risk of differentiated thyroid carcinoma (DTC) have been widely studied but the findings are contradictory. METHODS: We performed a meta-analysis in the present study using STATA 11.0 software to clarify any associations. Electronic literature databases and reference lists of relevant articles revealed a total of 10, 6 and 6 published studies for the Arg399Gln, Arg194Trp and Arg280His polymorphisms, respectively. RESULTS: No significant associations were observed between Arg399Gln and DTC risk in all genetic models within the overall and subgroup meta-analyses, while the Trp/Trp vs Arg/Arg and recessive model of the Arg194Trp polymorphism was associated with DTC susceptibility, and the dominant model of Arg280His polymorphism contributed to DTC susceptibility in Caucasians. CONCLUSIONS: Our meta-analysis suggests that XRCC1 Arg194Trp may be a risk factor for DTC development.

[Using multivariate multilevel logistic model to study the influential factors of attitudes related to the Punishment on Smoking, among the residents in Guangzhou].

OBJECTIVE: To explore the attitudes towards the Smoking Ban policy and the bias in different levels of related society sanctions so as to provide evidence for implementing anti-smoking measures in the public places. METHODS: A multi-univariate-multilevel logistic model was developed to find the relation between penalty attitudes and the covariates' effects. RESULTS: 74.6% (3647/4892) and 61.2% (2994/4892) of the residents agreed to punish either the managers of public places or to the smokers. The two kinds of attitude were associated (χ2=1253.45, P<0.0001). Residents being female, aged between thirty and fifty-nine years old, having had higher than college education, being non-current smokers, with high scores on knowledge of tobacco control, tended to have the attitude of punishing the public place managers and smokers. However, those persons exposed to everyday secondhand smoke or being non-current smokers, tended to punish the smokers in the generalized Wald test. CONCLUSION: There was strong evidence noticed that most of the residents in Guangzhou had supported the 'tobacco control penalty'. Factors as age, sex, level of education received, knowledge on hazards of smoking, being current smokers and under secondhand smoke exposure were the influencing factors. Non-current smokers and those who exposed to secondhand smoke everyday, would prefer to take different penalties policies.

[Using log-binomial model for estimating the prevalence ratio].

To estimate the prevalence ratios, using a log-binomial model with or without continuous covariates. Prevalence ratios for individuals' attitude towards smoking-ban legislation associated with smoking status, estimated by using a log-binomial model were compared with odds ratios estimated by logistic regression model. In the log-binomial modeling, maximum likelihood method was used when there were no continuous covariates and COPY approach was used if the model did not converge, for example due to the existence of continuous covariates. We examined the association between individuals' attitude towards smoking-ban legislation and smoking status in men and women. Prevalence ratio and odds ratio estimation provided similar results for the association in women since smoking was not common. In men however, the odds ratio estimates were markedly larger than the prevalence ratios due to a higher prevalence of outcome. The log-binomial model did not converge when age was included as a continuous covariate and COPY method was used to deal with the situation. All analysis was performed by SAS. Prevalence ratio seemed to better measure the association than odds ratio when prevalence is high. SAS programs were provided to calculate the prevalence ratios with or without continuous covariates in the log-binomial regression analysis.

Hemodynamic effect of apelin in a canine model of acute pulmonary thromboembolism.

The peptide apelin is expressed in the pulmonary vasculature and is involved in the pathogenesis of many cardiovascular diseases. It has a biphasic role in the regulation of vasomotor tone related to the vascular endothelium. In this study, we induced acute pulmonary embolism (APE) in dogs with autologous blood clots to assess the effect of apelin on pulmonary and systemic circulation in the acute phase of APE. The expression of apelin mRNA was found to be upregulated in the lung tissue in the early several hours after APE induction and decreased at 24 h. The expression of apelin protein in the pulmonary arteries did not change within 24 h after APE, but significantly increased in the bronchial epithelial cells as early as 1h and decreased at 24 h. In normal anesthetized dogs, intravenous bolus administration of apelin significantly reduced the mean arterial pressure (MAP), but did not significantly affect the mean pulmonary arterial pressure (MPAP). In the dogs with APE, apelin decreased MPAP, whereas its impact on MAP was not significantly different from that in the control group. Taken together, the level of endogenous apelin did not change significantly in the pulmonary arterial wall, whereas its expression in the bronchial epithelium was upregulated in the early stage of APE. The effect of exogenous apelin on vasomotor tone was complicated: it resulted in differential changes in the pulmonary and systemic arterial pressures under different physiological and pathological conditions.

[A 1:1 matched case-control study on the interaction between HBV, HCV infection and DNA repair gene XPC Ala499Val, Lys939Gln for primary hepatocellular carcinoma].

OBJECTIVE: To evaluate the interaction between environmental factors, HBV/HCV infections and DNA repair gene XPC exon 8 Ala499Val, exon 15 Lys939Gln on related risks to primary hepatocellular carcinoma (PHC). METHODS: A 1:1 matched case-control study was conducted in Shunde city, Guangdong province. The genotypes of Ala499Val and Lys939Gln were detected by polymerase chain reaction restrictive fragment length polymorphism (PCR-RFLP) analysis, and gene-environment interactions were analyzed by conditional logistic regression. RESULTS: Among people infected by HBV with non- or at least one mutant gene of Ala499Val carriers, the risk of PHC significantly increased, with ORs as 3.768 (95%CI: 1.137 - 12.485) and 3.667(95%CI: 1.122 - 11.981) respectively. With non- or at least one mutant gene of Lys939Gln, the risk was increasing with ORs as 6.778 (95%CI: 2.025 - 22.688) and 3.152 (95%CI: 1.062 - 9.351) respectively. In those with HCV infection, non- or at least one mutant gene of Ala499Val might increase the risk with ORs as 2.955 (95%CI: 0.587 - 14.869), 1.085(95%CI: 0.307 - 3.839) respectively. However, when compared to the ones with no mutant gene of Lys939Gln among the same research subjects, those carrying at least one gene may decrease the risk, with OR lowered from 4.197 (95%CI: 0.870 - 20.243) to 0.887 (95%CI: 0.228 - 3.448). But the interactions between HBV infection, HCV infection and XPC genes were not statistically significant. CONCLUSION: Among people infected by HCV, the mutant gene of Ala499Val had the tendency to lower the risk of PHC, and the mutant gene of Lys939Gln also appeared the same in the population with either HBV infection or HCV infection in Shunde, Guangdong. Another study with large samples should be performed to analyze the interactions among environments-genes.

[Study on inhibitory effects of c9, t11-conjugated linoleic acid on migration of human gastric carcinoma cell line via cyclooxygenase-2 pathway].

OBJECTIVE: To study the inhibitory effects of c9, t11-conjugated linoleic acid (c9, t11-CLA) on migration of human gastric carcinoma cell line (SGC-7901) via cyclooxygenase-2 (COX-2) pathway. METHODS: After inhibiting COX-2 activity by 100 micromol/L COX-2 inhibitor NS-398 in SGC-7901 cell, we treated SGC-7901 cells with c9, t11-CLA at a concentration of 200,100, 50, 25 micromol/L for 24 h, respectively. Using reconstituted basement membrane invasion, adhesion, chemotaxis assays, we detected the effect of c9, t11-CLA and COX-2 on the cell migration. RESULTS: Compared to NS-398 group, 200, 100 micromol/L c9, t11-CLA significantly suppressed SGC-7901 cells invading into the reconstituted basement membrane (F = 14.309, P = 0.000; F = 19.005, P = 0.000). 200 micromol/L c9, t11-CLA significantly inhibited SGC-7901 cells adhering to laminin, fibronectin and Matrigel (F = 3.063, P = 0.021; F = 6.692, P = 0.001; F = 11.999, P = 0.000). The chemotaxis of SGC-7901 cells and inhibitory frequency were significantly decreased in the 200 micromol/L c9, t11-CLA group (F = 1.380, P = 0.276). CONCLUSION: c9, t11-CLA inhibits invasion, adhesion and chemotaxis of SGC-7901 cells, and the COX-2 plays an important role in the process. [ Key words]

[Studies on the cytological characters of the interspecific hybrid F1 among the cultivated species in Gossypium and their genetic relationship].

Interspescific hybridization among four cultivated species in Gossypium (G. herbaceum, G. arboreum, G. hirsutum and G. barbadense) were carried out to produce dispecific hybrids F1, (G. arboreum x G. herbaceum) F1 and (G. hirsutum x G. barbadense) F1, and quadrispecific hybrid F1, which was produced by crossed the chromosome doubled (G. arboreum x G. herbaceum) F1 with (G. hirsutum x G. barbadense) F1. In order to study the evolution relationship among the four cultivated species in Gossypium, the characteristic of chromosome behavior during the meiosis and pollen viability in those interspecific hybrids F1 were studied in this paper. The results showed that the diploid interspecific hybrid, (G. arboreum x G. herbaceum) F1, had a four-chromosome-ring, the chromosome configuration was 2n = 26 = 11 II + 1 IV. And the normal pollen percent was 50.71%, which showed the character of typical gamete semi-sterility, and approved that there was a chromosome translocation between the two diploid cotton species, G. arboreum and G. herbaceum. For the allotetraploid species interspecific hybrid F1, (G. hirsutum x G. barbadense) F1, most of the chromosomes at metaphase I could be paired into bivalents, with a few number of univalents, trivalents, and quardrivalents. The chromosome configuration was 2n = 52 = 0.78 I +22.24 II +0.94 III +0.98 IV, with a normal pollen rate of 54. 84%. The experiment showed that there were a few chromosome translocation or chromosome inversion between the two allotetraploid cotton species, G. hirsutum and G. barbadenses. The meiosis of the quardrispecific hybrid F1 was abnormal, and the loss of chromosomes was common. Most of the chromosomes could not synapse at metaphase I, which led to many univalents and some multivalents. The chromosome configuration of the quardrispecific hybrid F1 was 2n = 52 = 5.45 I +14.41 II +2.44 III +1.59 IV +0.63 V +0.15 VI, and the normal pollen rate was 6.87%, which showed that the relationship of four cultivated cotton species was relatively closed. It is possible to produce a new germplasm with the good characters of the four cultivated species through genetic recombination.

[Effects of conjugated linoleic acid on the expression of critical enzymes of linoleic acid metabolism in tumor cell].

OBJECTIVES: To study the effects of c9,t11-conjugated linoleic acid (c9,t11-CLA) on critical enzymes of linoleic acid metabolism in stomach granular cell (SGC-7901). METHODS: SGC-7901 was treated with c9,t11-CLA by 200, 100, 50 or 25 micromol/L for 24 hours. The effects of c9,t11-CLA on the cell proliferation was measured by monotetrazolium and the expression of Delta6-desaturase, Delta5-desaturase, COX-1, COX-2, 5-LOX mRNA were measured by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: At a concentration of 200, 100, 50, or 25 micromol/L, c9,t11-CLA suppressed the proliferation of SGC-7901 by 54.3%, 20.5%, 10.5% and 2.93%. The c9,t11-CLA might decrease the expression of COX-2 mRNA, and increase the expression of Delta6-desaturase and COX-1 in SGC-7901, but might not affect Delta5-desaturase and 5-LOX. CONCLUSION: The effects of c9,t11-CLA on the COX and Delta6-desaturase might play an important role in mediating the ability of c9,t11-CLA as to inhibiting the proliferation of tumor cells, and the anti-cancer activity by c9,t11-CLA might be associated with the linoleic acid metabolism.

Effects of c9,t11-conjugated linoleic acid on adhesion of human gastric carcinoma cell line SGC-7901.

AIM: To investigate the effect of c9,t11-conjugated linoleic acid (c9,t11-CLA) on the adhesion of human gastric carcinoma cell line (SGC-7901). METHODS: SGC-7901 cells were at first treated with different concentrations (25, 50, 100, 200 micromol/L) of c9,t11-CLA and 1 mL/L ethanol (as a negative control) for 24 h. Using adhesion assay and Western blot, we investigated the ability of SGC-7901 cells to adhere to intracellular matrix and examined the expression of E-cadherin (ECD), alpha-catenin, intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) in these cells. RESULTS: The attachment rate to laminin of SGC-7901 cells treated with different concentrations of c9,t11-CLA (0, 25, 50, 100, and 200 micromol/L) was 100.0+/-3.3, 95.7+/-4.0, 89.2+/-4.6, 87.9+/-6.1, and 65.9+/-5.8, respectively. The attachment rate to fibronectin was 100.0+/-4.7, 96.8+/-3.8, 94.5+/-4.1, 76.5+/-4.3, and 61.8+/-4.8, respectively. The attachment rate to Matrigel was 99.9+/-6.6, 91.4+/-6.8, 85.5+/-7.4, 79.3+/-5.6, and 69.6+/-5.1, respectively. Besides, c9,t11-CLA could increase the level of ECD and alpha-catenin, and decrease the level of ICAM-1 and VCAM-1 in SGC-7901 cells. CONCLUSION: c9,t11-CLA can reduce the adhesion of human gastric carcinoma cells to laminin, fibronectin and Matrigel. c9,t11-CLA can increase the level of ECD and alpha-catenin, and decrease the level of ICAM-1 and VCAM-1 in human gastric carcinoma cells.

[A new statistical method on familial correlation dealing with family data from case-control studies].

OBJECTIVE: This paper presents a statistical method of familial correlation on family data from case-control studies. METHODS: Marginal mean models of the probands and the relatives conditional on the proband's disease status, as well as the marginal association model of the relatives were modeled integrately. Conditional odds-ratio and marginal odds-ratio were used to measure the familial correlation. RESULTS: The parameter's interpretation in the model was in accordance with sample characteristics. This method is more efficient due to making fully use of information of the probands and relatives. In addition, the method has all advantages of GEE2. CONCLUSION: The method in this paper efficiently and conveniently analyzes the family data from case-control studies to estimate the familial correlation on disease.

Protective effect of M3 receptor on H2O2 -induced apoptosis of rat myocardial cells in vitro.

AIM: To observe the effect of activation of M3 receptor on H2O2 induced apoptosis in cultured rat myocytes and to investigate its possible mechanisms. METHODS: Isolated neonatal cardiomyocytes were cultured. Morphologic changes were observed by microscopy. The apoptosis in cardiomyocyte was detected by terminal deoxynucleotide transferase directed d-UTP nick and end labeling (TUNEL) assay. The expression of apoptosis-related protein in Bcl-2 and Fas was measured by immunohistochemistry assay. [Ca2+]i in single cardiomyocyte loaded with Fluo 3-AM was measured by confocal microscope. RESULTS: H2O2-mediated myocyte apoptosis was attenuated by M3 receptor agonist choline (10 mmol x L(-1)). Pretreatment of cardiac myocytes with choline also increased Bcl-2, decreased Fas expression, and inhibited the increase in FI value of [Ca2+]i in H2O2-stimulated cardiac myocytes. However, blockade of M3 receptor by 4DAMP (10 nmol x L(-1)) completely inhibited the effects of choline on H2O2-stimulated cardiac myocytes. CONCLUSION: Activation of M3 receptor showed protective effect on H2O2-induced apoptosis in cultured rat myocytes and this effect might be related to modulating the expression of some genes including Bcl-2 and Fas as well as the downregulation of [Ca2+]i.

Inhibitory effects of c9, t11-conjugated linoleic acid on invasion of human gastric carcinoma cell line SGC-7901.

AIM: To investigate the effect of c9, t11-conjugated linoleic acid (c9, t11-CLA) on the invasion of human gastric carcinoma cell line and its possible mechanism of preventing metastasis. METHODS: Using reconstituted basement membrane invasion, chemotaxis, adhesion, PAGE substrate zymography and RT-PCR assays, we analyzed the abilities of invasion, direct migration, adhesion of intracellular matrix, as well as the activity of type IV collagenase and expression of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 mRNA in SGC-7901 cells which were treated with gradually increased concentrations (25, 50, 100 and 200 micromol/L) of c9, t11-CLA for 24 h. RESULTS: At the concentrations of 200 micromol/L, 100 micromol/L and 50 micromol/L, c9,t11-CLA suppressed the invasion of SGC-7901 cells into the reconstituted basement membrane by 53.7 %, 40.9 % and 29.3 %, respectively, in comparison with the negative control. Only in the 200 micromol/L c9,t11-CLA group, the chemotaxis of SGC-7901 cells was inhibited by 16.0 % in comparison with the negative control. C9,t11-CLA also could inhibit the adhesion of SGC-7901 cells to laminin, fibronectin and Matrigel, increase the expression of TIMP-1 and TIMP-2 mRNA, and reduce type IV collagenase activities in the serum-free medium supernatant of SGC-7901 cells. CONCLUSION: c9,t11-CLA can inhibit the invasion of SGC-7901 cells at multiple procedures in tumor metastasis cascade, which may be associated with the induction of TIMP-1 and TIMP-2 mRNA expression.