铅对大鼠中枢神经系统中NOS的影响

EFFECT OF LEAD ON NOS IN CENTRAL NERVOUS SYSTEM OF RATS.

本文采用 SD成年大白鼠饮用醋酸铅水染毒 30天 ,然后用改进的 NADPH测定法及免疫组化 SP法观察脑组织中 NOS酶活性及 NOS酶蛋白亚型的变化。大白鼠分为五组 ,3个剂量组 ,高铅组为 2 0 .0 g/ L 醋酸铅 ,中铅组为 5 .0 g/ L 醋酸铅 ,低剂量为 1.0 g/ L 醋酸铅 ,分别经饮水染毒 ;阳性对照组为 1.0 g/ L 天冬酸 ;阴性对照组为普通自来水。结果显示 ,染铅组脑组织海马及小脑的 NOS酶活性水平明显下降 ,小脑区 n NOS及 i NOS蛋白与对照相比无显著性差异 ,而海马区的i NOS酶蛋白的表达高于对照组。这一结果表明 ,铅染毒后对大鼠中枢神经系统中 NOS酶活性具有抑制作用 ,这可能是铅中毒引起学习记忆功能障碍的重要机制之一。

Changes of the NOS activity and the expression of NOS protein in central nervous systems of rats,which were subacutely intoxicated with oral exposure to lead acetate for 30 days,were observed with improved NADPH techniques and immunohistochemistry to study neurotoxic mechanism of lead.The rats were divided into five groups.Three groups were exposed to 1 0g/L、5 0g/L and 20 0g/L of lead acetate in drinking water,respectively.Positive control was 1 0g/L aspartic acid.Negative control was tap water.Results showed that the activity of NOS enzyme were dramatically suppressed in both hippocampus and cerebellum,but the expression of iNOS protein were higher than those in controls with immunohistochemical method.It revealed that lead could restrain NOS at the enzyme activity level,which probably is one of important molecular mechanism of the damage in learning and memory functions.