母体慢性铅暴露对子代鼠在体海马齿状回长时程增强的影响

Effect of Chronic Lead Exposure of Mother Rat on Long-Term Potentiation in the Hippocampal Dentate Gyrus in Vivo of their Offsprings

目的 :探讨母体慢性铅暴露对子代鼠在体海马齿状回长时程增强 (long- term potentiation,L TP)的影响。方法 :饮蒸馏水和 0 .2 %醋酸铅溶液两组母鼠的子代鼠对应分为对照组和母体期铅暴露组 ,应用细胞外微电极记录单脉冲刺激穿通路纤维在海马齿状回诱发的群体锋电位 (population spides,PS) ,观察并比较两组于高频刺激(high- frequency stim ulation,HFS)前后的 PS幅值变化。结果 :HFS前 ,基线记录的两组 PS平均幅值及峰潜伏期无显著差异 ;HFS后 ,母体期铅暴露组 L TP发生率虽与对照组无显著差异 ,但其 L TP增幅减小 ,并出现了短时增强转为抑制及 L TD型反应。统计显示母体铅暴露组 HFS后 PS振幅的平均增强率显著低于对照组 ,对照组平均增强至基线值的 (138.2± 10 .4) % ,母体期铅暴露组为基线值的 (10 8.8± 2 0 .7) %。结论 :母体慢性铅暴露可损害子代鼠海马齿状回 L TP的在体诱导和维持 ,且以维持过程受损为主。

Objective:Our purpose was to investigate the effects of chronic lead exposure of mother rat on long term potentiation (LTP) in vivo of their offsprings. Methods: Two groups of female Wistar rats were fed with distilled water or 0.2% lead acetate during the whole gestation and suckling period. Their offsprings underwent electrophysiological examination. Population spikes (PS) were recorded in the dentate gyrus in response to single pulse stimulation applied to perforant path (PP) with extracellular microelectrode technique. Results: The recordings of PS baseline evoked by single pulse stimulation revealed no differences between the control and the maternally Pb exposed group with respect to the mean PS amplitude and peak latency. After the high frequency stimulation (HFS), the difference in incidence of LTP induction in control and maternally Pb exposed group was also still non significant. However, the increase in relation to the baseline values (100%) of mean PS amplitude after HFS in maternally Pb exposed group was significantly smaller than that in the control group. In the control group, the mean PS amplitude increased to (138.2±10.4)% from the baseline values; in the maternally exposed group, to (108.8±20.7)%. Conclusion: Chronic lead exposure of mother rat may impair LTP in vivo of their offsprings .