妊娠期母体低水平铅暴露对大鼠子代学习记忆能力的影响

Effects of prenatal exposure to low level lead on learning and memory of rats' offspring

目的探讨大鼠妊娠期间低水平铅暴露对其子代学习记忆能力的影响。方法孕鼠随机分为4组,3个处理组自怀孕第1天起分别给予醋酸铅含量为125、250和500 mg/L的饮水,对照组给予不含铅的双重蒸馏水,采用流动注射氢化物发生-原子吸收光谱法测定仔鼠血铅、脑海马组织铅含量,以避暗穿梭箱试验、Morris水迷宫试验测定仔鼠的学习记忆能力。结果各处理组的1、21 d龄仔鼠血铅、海马组织铅水平明显高于对照组仔鼠,差异有统计学意义(P＜0．05),至60 d龄,差异无统计学意义(P＞0．05)；Morris水迷宫试验显示,各处理组21、60 d龄仔鼠连续4 d训练期间,第2、3、4天潜伏期均高于同期对照组仔鼠,差异有统计学意义(P＜0．05)；避暗穿梭箱试验显示,各处理组21、60 d龄仔鼠连续5 d训练期间,主动回避次数低于同期对照组仔鼠,差异有统计学意义(P＜0．05)；主动回避潜伏期、被动回避潜伏期高于同期对照组仔鼠,差异有统计学意义(P＜0．05)。结论母体妊娠期低水平铅暴露可以影响仔鼠的空间学习记忆能力,且影响至少可持续至仔鼠成熟期。

Objective To explore the effects of prenatal exposure to low level lead on learning and memory of rat＇s offspring. Methods The pregnant rats were randomizedly divided into 4 groups and provided with doubly evaporated water in the control group and 125,250 and 500 mg/L lead acetate solution via drinking water in three exposed groups respectively during the pregnancy. The learning and memory ability of 21-day old and 60-day old offsprings were tested by the Morris water maze and the shuttling and avoiding dark box respectively. Results The blood and hippocampus lead centrations of 1-day old and 21-day old offspring in the 3 lead-exposed groups were significantly increased compared with the control group（ P 〈 0.05）, while at the period of 60-day old there was no significant difference bewteen them. The time to find the platform in Morris water maze for 21-day old and 60-day old offsprings of the 3 lead in the exposed groups was significantly increased compared with the control group during the 4 days training（ P 〈 0.05） .The times of initiative avoiding in the shuttling and avoiding dark box for 21-day old and 60 - day old offsprings in the 3 lead-exposed groups were significantly decreased, while the latency of the initiative avoiding and latency of the passive avoiding were significantly increased compared with the control group （ P 〈 0.05）. Conclusion Prenantal exposure to low level lead impaired the space learning and memory ability of offsprings of the rats, and this kind of influence will continue till the offspring＇ s maturity.