Abstract:

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 (P<0.05 or P<0.01). There was no significant difference in the indices between cells treated with 1000 mg/L of thiamine or 500nmol/L of riboflavin and positive controls (P>0.05). 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.

Key words: thiamine, riboflavin, DNA damage, single cell gel electrophoresis