Objective To study H2O2-induced single strand breaks(SSB) formation in DNA and the reparation in NIH3T3 mouse fibroblasts by single cell gel electrophoresis technique(SCGE,Comet Assay) and to introduce SCGE.Methods The NIH3T3 mouse fibroblasts were incubated,and cell damage was induced by H2O2 and determined by SCGE.Results ① H2O2-induced damage class graph of the DNA Comet in the NIH3T3 mouse fibroblasts was established.② H2O2-induced SSB was H2O2 dose-dependent.③ The reparation of the damaged DNA was time-dependent and could be achieved 15min after incubation.The data indicated that most reparations were completed within 1 hour,but a few might take longer time.Conclusion Single cell gel electrophoresis technique is a simple and sensitive method to determine oxidation-induced single strand breaks(SSB) formation in DNA.

AIM: To investigate the preventive effects of Shengmai San (SMS) on oxidative damage in mentally stressed mice.METHODS: An oxidative stress mouse model was established by moustache-removed. Protein carbonyl and thiobarbituric acid reactive substance (TBARS) formation were determined as the oxidative stress markers.RESULTS: (1)Moustache-cut was founded to significantly enhance the behavioral movements of mice, especially large movements (movement 2 and rearing). SMS pre-administration inhibited the accelerated movements. (2) Protein carbonyl was increased in brain, heart, liver and kidney. TBARS in liver and heart increased in the moustache-cut mice, but SMS pretreatment inhibited the increased protein carbonyl and TBARS.CONCLUSION: SMS has the preventive effects on oxidative damage induced by emotional stress.