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Objective To explore the effects of thiamine and riboflavin on H2O2-induced DNA oxidative damage in human umbilical vein endothelial cell line ECV304.Methods ECV304 cells were incubated with 10,100,500,1000 mg/L of thiamine or 20,100,300,500 nmol/L of riboflavin for 24 h,and then oxidative damage of cells were induced by 25 mol/L H2O2 for 30 min.DNA damage was detected with single cell gel electrophoresis(SCGE)assay.ECV304 cells incubated without H2O2,thiamine and riboflavin were served as negative controls,and those incubated with H2O2 and without thiamine and riboflavin were served as positive controls.Results H2O2 induced DNA damage,and the indices of percent of DNA damage cells,percent of tail DNA,tail length and Olive tail moment were increased.The indices of cells pretreated with 10,100,500 mg/L of thiamine or 20,100,300 nmol/L riboflavin were significantly decreased(P0.05).Conclusion Proper supplementation of thiamine and riboflavin may decrease H2O2-induced DNA oxidative damage,while excess thiamine and riboflavin supplementation may be harmful to DNA and enhance the susceptibility to H2O2 potentially.
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<p><b>OBJECTIVE</b>To investigate the effects of Hovenia dulcis extract on mRNA expression of MMP-13 and TIMP-1 mRNA in hepatic tissue in experimental rats.</p><p><b>METHOD</b>48 male Sprague-Dawley rats were randomly divided into 2 groups: normal group (16) and model group (32), hepatic fibrosis was induced by CCl4 for 6 weeks in rats, 8 rats were sacrificed at the end of the 6th week from every group respectively, HE staining of hepatic tissue was performed; In the model group, rats randomly subdivided into 3 groups: spontaneous recovery group, control group and medication administration group, 8 rats were sacrificed at the end of the 12th week from every group respectively, the mRNA levels of MMP-13 and TIMP-1 in hepatic tissue were assayed by semi-quantitative RT-PCR.</p><p><b>RESULT</b>The mRNA expression of MMP-13 among the 4 groups were not statistically significant, but the mRNA expression of TIMP-1 among the 4 groups were statiscally significant. The levels of TIMP-1 mRNA were significantly increased in control group and medication administration group compared, with those in the model group (P < 0.05), and reverse effects of medication administration groups were significantly high than those of control group (P < 0.05).</p><p><b>CONCLUSION</b>Inhibition of the mRNA expression of TIMP-1 may be the mechanism of reversing hepatic fibrosis H. dulcis, for thus collogen degradation system was recoveried gradually.</p>