Abstract: Objective Rat offsprings exposed to lead during pregnant and breast-feed period were used to determine the lead content in blood and brain of the 7th or 21st day after birth.Bcl-2 and Fas protein expression in hippocampus was also determined.Methods Pb concentration in blood and brain was determined by atomic absorption spectrophotometry.Bcl-2、 Fas protein expression were estimated by immunohistochemical study.Results For the offsprings on the 7th day after birth,Bcl-2 protein expression in Pb-exposed groups decreased compared with the control,and Fas protein expression increased at the same time.On the contrary,for the offsprings on the 21st day after birth,there was no such change as that in the 7th day offsprings.Conclusion Lead can induce excessive apoptosis through changing the protein expression of Bcl-2 and Fas,and then induce its developmental neurotoxicity.