母体铅暴露对大鼠子代学习和记忆的影响

目的 研究母体铅暴露对大鼠子代学习和记忆的影响。方法 孕鼠随机分为4组,从孕期第1天至仔鼠出生第20天断乳分别饮用双蒸水、50、100和200 mg,/L醋酸铅溶液。水迷宫测试20 d龄仔鼠学习能力;Y迷宫测试20、40、60 d龄仔鼠主动学习和记忆能力。结果 仔鼠水迷宫错误次数随母鼠铅暴露剂量增加而增加,100和200 mg/L组明显高于对照组(P<0.05或P<0.01),逃避潜伏期只有高剂量组长于对照组(P<0.05)。各剂量组仔鼠Y迷宫0 min、10 min和24 h逃避达标率20 d龄时最低,停止接触铅以后有所恢复,到60 d龄时达最高;在60 d龄时各剂量组仔鼠的10 min逃避达标率与对照组差异无显著性(P>0.05),而100和200mg,/L组0 min、24 h逃避达标率仍显著低于对照组(P<0.05或P<0.01)。结论 母体铅暴露先损伤仔鼠的学习和记忆能力,其次损伤运动能力。停止铅暴露后短时记忆能力恢复较好,学习、长时记忆能力恢复较差。

Effects of Prenatal Exposure to Lead on Learning and Memory of Rats'''' Offspring

Objective To explore the effects of prenatal exposure to lead on learning and memory of rats' offspring. Methods The pregnant rats were randomly divided into 4 groups provided with double evaporated water, 50, 100 and 200 mg/L lead acetate solution via drinking water respectively. The lead-exposure period for exposure groups was limited from the 1st day after pregnancy to the 20th day when the offspring began to be weaned. For learning ability 20-day old offspring were tested by water maze. For active learning and memory ability, the 20-day old, 40-day old and 60-day old offspring were tested by Y maze. Results The frequency of the mistakes in water maze made by offspring increased with the increase of the prenatal lead-exposure doses of their mothers and showed significantly higher levels in 100 and 200 mg/L groups compared with that of control group (P<0.05 or P<0.01). Only the 200 mg/L group showed significantly longer incubation period of escape compared with that of control group (P<0.05). The qualified rates of 0-min, 10-min and 24-h escape of Y maze test for each dose group revealed the lowest levels when the offsping were 20-day old, and increased gradually after the offspring were suspended for exposure to lead and reached the peaks when they were 60-day old. The qualified rates of 0-min escape for each dose group showed no significant differences compared with that of control group when they were 60-day old (P>0.05). But the qualified rates of 0-min and 24-h escape for 100 and 200 mg/L groups showed sigificantly lower levels compared with that of control group when they were 60-day old (P<0.05 or P<0.01). Conclusion Prenatal exposure to lead impaired the learning and memory ability first, then the locomotion ability of offspring. After the offspring were suspended to be exposed to lead, the working memory ability could be recovered better, but the reference memory ability and learning ability couldn't be recovered quite well.