铅接触仔鼠学习记忆行为与海马bcl-2和bax基因表达

Effects of Lead Exposure on Filial Rats' Learning and Memory Behavior and Expression of bcl-2 and bax Gene in Hippocampus Formation

目的 通过对宫内及哺乳期铅接触仔鼠海马bcl 2和bax基因表达水平的检测 ,探讨其在铅引起学习记忆障碍中的作用。方法 采用饮水中加入醋酸铅的方法染毒SD大鼠 (2 0 ,2 0 0 ,2 0 0 0mg/L) ,6周后交配 ,自然分娩 ,于仔鼠断乳后停止铅接触。用暗室电击试验测试仔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S -P免疫组织化学法测定海马bcl 2和bax基因表达产物。结果 3个染铅组仔鼠学习记忆能力与对照组相比明显下降 ,染铅组仔鼠血铅和脑铅浓度均明显高于对照组 ,差异有显著性 (P <0 0 5 )。免疫组织化学测定结果显示 ,在海马CA1,CA3,DG (齿状回 )区 ,bcl 2表达平均灰度值各染铅组与对照组相比 ,差异有显著性 (P <0 0 1) ,即染铅组表达低于对照组 ;bax表达平均灰度值中、高剂量染铅组与对照组相比 ,差异有显著性 (P <0 0 1) ,即染铅组表达高于对照组。结论 宫内和哺乳期铅接触可损害仔鼠的学习记忆能力 ,作为凋亡调控基因bcl

Objective To investigate the effects of lead exposure of filial rats in the duration of intrauterine and lactation on learning and memory behavior and the expression of bcl 2 and bax gene in hippocampus formation and their correlation.Methods SD rats were administrated with 0,20,200,and 2 000 mg/L lead acetate in drinking water for 6 weeks,and then mated.Their offspring exposed to lead only in the duration of intrauterine and lactation.After postnatal 21 days,the offspring underwent dark room electric stroke test to study the effects of lead on learning and memory ability.Their blood and brain lead was determined by atomic absorption spectrophotometry.The expressions of bcl 2 and bax gene were measured with S-P immunohistochemistry.Results Compared with the control,the learning and memory ability of lead exposed ones was significantly decreased;and the blood and brain lead levels of three lead exposed offspring were significantly higher than those of the control (P<0 05). The result of immunohischemistry indicated that in hippocampus CA1,CA3,DG region,the expression intensity of bcl 2 of three lead exposed offspring was significantly lower than those of the control (P<0 01). The expression intensity of bax in 200 and 2 000 mg/L lead exposed offspring was significantly higher than that of the control(P<0 01).Conclusions Results indicated that lead exposure in the duration of intrauterine and lactation could induce learning and memory behavior defects in filial rats.As a regulating and control gene of apoptosis,bcl 2 and bax might participate in hippocampus neuron apoptosis induced by lead.