Objective To study the mechanism of neuronal apoptosis induced by on DNA damage and cell cycle changes in nerve cells after exposed to benzoapyrene (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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