Forty 20-day-old female Kunming mice were divided randomly into 3 treatment groups and 1 control group with 10 of each groups. The 3 treatment groups were injected abdominaly with 10,20 and 40 mg of lead acetate per kilogram of body weight for 2 days respectively,and the control group injected with the same volume of normal saline as the 3 treatment groups. The apoptosis rates of granulosa cells were detected by the TdT-mediated dUTP-biotin nick end labeling （TUNEL） and preparation of paraffin section on days 1 and 3 post-injection respective...
