Effects of lead exposure on learning and memory ability and β-amyloid protein level in hippocampus of mice at different age stages

Aim: To explore the effects of lead exposure on the ability of spatial learning and memory and β-amyloid protein( Aβ) level in hippocampus of mice at different age stages. Methods: Healthy male mice were randomly allocated into growing exposure group( drinking 2 g / L Pb containing water from birth to 21 days by breast milk),adulthood exposure group( drinking 2 g / L Pb containing water from 180 days to 240 days after birth),joint exposure group( lead exposed at growing period and adulthood) and control group( drinking deionized water),10 mice in each group. After 1 year,the spatial learning and memory ability was evaluated by Morris water maze( MWM),and the level of Aβ in hippocampus was measured by ELISA. Results: The escape latency in each group measured at different days had significant difference( Ftime= 396. 688,P 0. 001),and there were also differences between different groups( Fgroup= 177. 902,P 0. 001).And compared with the control group,the numbers of platform cross significantly decreased( F = 30. 394,P 0. 001). The numbers of platform cross in the growing exposure group and the joint exposure group were less than the adulthood exposure group( P 0. 05). The level of Aβ in hippocampus in lead exposure groups were significantly higher than that in control group( F = 346. 032 and 53. 796,P 0. 001),and the levels of Aβ in both the growing exposure group and the joint exposure group was higher than that in the adulthood exposure group( P 0. 05). Conclusion: Lead exposure can lead to the accumulation of Aβ in hippocampus and the damage of spatial learning and memory ability. These accumulation and damage are more severe when the mice get lead exposure in growing time.