Homocysteine thiolactone induced the apoptosis of human umbilical vein endothelial cells

Objective: To investigate the effects of homocysteine thiolactone （HcyT） on apoptosis and caspase3 expression in human umbilical vein endothelial cell （HUVEC） and study the role of some antioxidants （N-acetylcysteine NAC, vitamin E VitE, and pyrrolidine dithiocarbamate PDTC） in the reduction of HcyT -induced apoptosis. Methods: Flow cytometer and agarose electrophoresis of DNA fragmentation were applied to detect and observe cell aoptosis.mRNA and protein expression of caspase3 were determined by RT-PCR and Western blotting. Results: HcyT could induce cell apoptosis in a concentration-dependent manner. The mRNA and protein expression of caspase3 were up-regulated in concordance with the increased HcyT concentration. NAC, VitE, or PDTC reduced HcyT-indued apoptosis,concurrently down-regulated caspase3 expression. Conclusion: HcyT exerted its genotoxic effects on HUVEC through an apoptotic pathway, in which caspase3 might play an important role.The strong antioxidant character may largely account for effects of NAC, VitE or PDTC on apoptosis reduction induced by HcyT.