[Objective] To study the mechanism of neuronal apoptosis induced by on DNA damage and cell cycle changes in nerve cells after exposed to benzo[a]pyrene (BaP).
[Methods] The neurons from cerebral cortex of neonatal SD rats (1-3 d) were incubated for 5 days.Then the cells were divided into two lots.The first lot was separated into 5 groups,namely blank control,low-dose,medium-dose,high-dose and solvent control groups,and intoxicated by BaP with S9 added at final concentrations of 0,10,20,40μmol/L and dimethyl sulfoxide respectively,then incubated for 48 hours.The second lot was separated into 5 groups,treated with 20μmol/L BaP and cultured for 0 h,6 h,12 h,24 h,and 48 h respectively.DNA damage was detected by single cell gel electrophoresis (SCGE) assay and cell cycle changes by flow cytometry.
[Results] SCGE results suggested that compared with the blank control group and the solvent control group,the Olive tail moment,tail DNA percent and tail length of the 20 and 40 μmol/L groups were significantly increased,and the head DNA percent of both groups were significantly decreased (P<0.05).Compared with the 0 h group,the Olive tail moment,tail DNA percent and tail length of the 48 h group were increased notably,and the head DNA percent was reduced (P<0.05).The neuron percentages of G1 period and S period were significantly higher in the 48 h group than in the 0 h group (P<0.05).
[Conclusion] BaP could induce neural cell DNA cleavage and cell cycle re-entry.
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