宫内及哺乳期铅接触对子鼠学习记忆行为和海马神经元凋亡的影响

目的　探讨宫内和哺乳期铅接触子鼠学习记忆行为改变和海马结构神经元凋亡发生状况。方法　SD大鼠采用饮水加醋酸铅 2 0、2 0 0、2 0 0 0mg·L- 1 方法染毒 ,6周后交配 ,自然分娩 ,于子鼠断乳时停止铅接触 ,用暗室电击试验测试子鼠学习记忆行为改变 ;用原子吸收分光光度法测定血铅和脑铅含量 ;用HE染色和原位末端标记TUNEL法观察海马神经元细胞凋亡状况。结果　 3个染铅组子鼠学习记忆能力均比对照组明显下降 ,血铅和脑铅含量均明显高于对照组 ,差异有显著性 (P <0 .0 5 ) ;TUNEL染色结果显示 :中、高铅组子鼠海马CA1、CA3、齿状回 (DG)区神经元细胞凋亡指数均明显高于对照组 ,差异有显著性 (P <0 .0 5 )。结论　宫内和哺乳期铅接触可损害子鼠的学习记忆行为 ,其机制可能与铅导致海马神经元细胞凋亡有关。

The effects of lead exposure during intrauterine and lactation in filial rats on learning and memory behavior and neuron apoptosis in hippocampus formation

Objective To explore the effects of lead exposure during intrauterine and lactation in filial rats on learning and memory behavior and neuron apoptosis in hippocampus formation and the relationship between them. Methods SD rats were exposed to 20, 200 and 2000 mg·L -1 of lead acetate in their drinking water for 6 weeks, and then mated. Their offsprings were exposed to lead only during intrauterine period and lactation. Blood and brain lead of the offsprings were determined by atomic absorption spectrophotometry at postnatal day 21(PN21). Darkroom electric stroke test was applied to study the effects of lead on learning and memory abilities. The neuron apoptosis was examined with HE histochemstry and terminal deoxynucleotiodyl transferase mediated dUTP nick end labeling (TUNEL). Results Compared with those of the control, the learning and memory abilities of lead exposed offsprings were significantly decreased ( P <0.05). The blood and brain lead contents of lead exposed offsprings were significantly increased ( P <0.05). The apoptosis indices of the hippocampal neuron in CA1, CA3 and DG regions of lead exposed offsprings were significantly decreased than those of control ( P <0.05).Conclusion Lead exposure during intrauterine period and lactation can cause learning and memory behavior defects in filial rats. Hippocampus neuron apoptosis induced by lead might be an important pathologic basis for the damage of learning and memory abilities caused by lead.