Abstract: Objective To explore the effects of lead exposure in pregnant mice on the expression of tumor necrosis factor-α(TNF-α) protein in hippocampus of mouse pups.Methods Lead acetate was administered to pregnant mice in drinking water at the dosages of 0.3,1.0,and 3.0 g/L.Each group composed of 10 mice.At the 7th,14th,and 21st day after the birth,the lead contents in blood and hippocampus of the offspring were determined.At the 21st day,the learning and memory ability of the offspring mice were tested by Y-type maze,and the expression of TNF-α protein in hippocampus of the offspring was determined by immunohistochemistry assay.Results At the 7th,14th,and 21st day,the lead levels in blood and hippocampus of the offspring mice of the lead exposure groups were higher than those in control group(P <0.05).The results of Y-type maze demonstrated that T1,T2,and T3 for 21-day old offspring in the three lead exposed groups were significantly decreased compared with those of the control group(P < 0.05).The results of immunohistochemistry assay showed that the area densities of TNF-α positive immune reaction in CA1 area of mouse pups in 0.3,1.0,and 3.0 g/L lead acetate exposure groups(0.154±0.013,0.197±0.018,0.201±0.015) were higher than that of the control group(0.079±0.012,P < 0.05 for all),and the averages gray values of TNF-α in CA1 area of mouse pups in 1.0 and 3.0 g/L lead acetate exposure groups(102.36±36.76,86.36±31.52) were lower than that of the control group(223.41±52.21,P <0.05 for all).Conclusion Maternal lead exposure may induce accumulation of lead in the offspring,enhance the expression of TNF-α protein in hippocampus of pups and result in learning and memory damages.