铅对大鼠脑细胞一氧化氮合酶表达的影响

目的观察实验性铅中毒对大鼠脑细胞一氧化氮合酶(NOS)表达的影响,为进一步揭示铅的神经毒作用机制提供科学依据。方法取健康成年雄性SD大鼠24只,随机分为4组,每组6只,经腹腔注射醋酸铅连续染毒5d,剂量分别为25、50、100mg/kg体重,分别取海马、皮层部位脑组织,用免疫组化方法分别测定海马、皮层组织中神经元型一氧化氮合酶(nNOS)和依赖型一氧化氮合酶(iNOS)的蛋白含量。结果各剂量染铅组皮层、海马组织中iNOS表达与对照组相比,明显升高(P均<0.05),并有良好的剂量-反应关系(r=-0.727,P<0.05)。各剂量染毒组海马nNOS表达明显升高(P均<0.05),并有良好的线性关系(r=0.847,P<0.05),皮层组织nNOS表达无明显变化(P均>0.05)。结论铅所引起的神经细胞毒性可能通过铅诱导NOS的高表达,使得NO生成过多进而造成神经损害。

Effects on Nitric Oxide Synthase Expression in Rat Brain Induced by Lead

Objective To study the effects of lead exposure on NOS expression in rat brain, and provide scientific basis for the revealment of neurotoxic mechanisms of lead. Methods Adult male SD rats were divided into four groups randomly, six male rats each group. The rats were exposed to lead acetate at doses of 25, 50, 100 mg/kg bw respectively through IP. for 5 days. The expression of nNOS and iNOS in hippocampus and cerebral cortex were observed using immunohistochemical method. Results The expression of iNOS in the hippocampus and the cerebral cortex of each lead exposure group were significantly increased compared with the control group and showed significant dose,response relationships. The expression of nNOS in hippocampus of each lead exposure group increased significantly, while the expression of nNOS in the cerebral cortex showed no significant differences between the lead exposure groups and the control group. Conclusion Lead exposure may induce the over,expression of NOS, which cause the production of excessive amount of NO and damage the neural cells.