Establishment And Application Of The Method For Detection Of DNA Damage Of Thymocytes And Hippocampal Neurons In Mice In Vitro

Objective: To establish a method for detection of DNA damage of thymocytes in miceand explore the mechanism of DNA damage of thymocytes in mice exposed tobenezene and benzo(a)pyrene.Method: Alkaline single cell gel electrophoresis (SCGE,Comet assay) was used tomonitor the DNA damage. The experiment divided into three groups exposedto different concentration of benezene and benzo(a)pyrene respectively withor without metabolism activating system(S9Mix). And to evaluate the changed ofgrade of tail length of comet assay after adding N-acetylcysteine(NAC) to the damagegroups. Nitric oxide (NO) concentration of thymocytes in mice exposed tobenzene and benzo(a)pyrene were determined by colorimetric method.Results:1.Benezene(10^-6mol/L-10^-4 mol/L) with S₉Mix existed can lead to DNAdamage of thymocytes ,which suggests dose-effect relationships. P<0.05 comparedvalue of group B(a)P(10^-4 mol/L 10^-5 mol/L) with control without S₉Mix ,and P<0.01compared value of group B(a)P(10^-6mol/L- 10^-4 mol/L) with control with S₉Mixexisted ,which suggests dose-effect relationships.2.With or without S₉Mix, the NO concentration released from the thymocytes exposedto benezene and benzo(a)pyrene (10^-6 mol/L-10^-4 mol/L) didn't increase significantlyas compared with that of control.3. with S₉Mix existed, The DNA damage induced by benezene and benzo(a)pyrenecan be eliminate by adding NAC(0.1 μ mol/L-1.0 μ mol/L).Conclusions: l.This study indicates that benezene and benzo(a)pyrene can induce DNAdamage of the thymocytes in mice.