脑缺血／再灌注介导大鼠海马CA1区nNOS巯基去亚硝基化作用的研究

目的：探讨大鼠全脑缺血/再灌注介导的大鼠海马CA1区神经型一氧化氮合酶（ nNOS）巯基去亚硝基化对神经元损伤的作用及机制。方法将SD大鼠随机分为假手术组（ S组）、脑缺血/再灌注组（ I/R组）、给药组（ GSNO组、7-NI组、MK801组、NS102组、GYKI组）及溶剂对照组（生理盐水组、DMSO组）。采用四动脉结扎法构建大鼠全脑缺血/再灌注模型。运用生物素转化法检测蛋白质的巯基-亚硝基化，聚丙烯酰胺凝胶电泳、免疫印迹方法、焦油紫染色方法对nNOS巯基去亚硝基化水平以及大鼠海马神经元细胞的损伤进行研究。结果与S组相比，I/R组nNOS巯基亚硝基化水平明显降低（P＜0．05）；与I/R组相比，GSNO组、7-NI组以及MK801组nNOS巯基亚硝基化水平显著增高（P＜0．05），但GYKI组、NS102组、DMSO组以及生理盐水组与I/R组相比，差异无统计学意义。说明外源性一氧化氮（NO）供体GSNO、nNOS抑制剂7-NI、N-甲基-D-天冬氨酸（NMDA）受体抑制剂MK801能够抑制nNOS的去亚硝基化，对神经元起保护作用。结论大鼠全脑缺血/再灌注所致的大鼠海马CA1区nNOS巯基去亚硝基化在神经细胞损伤中有作用，其去亚硝基化是通过NMDA受体起作用；外源性NO供体GSNO、nNOS抑制剂7-NI也能够抑制nNOS的去亚硝基化从而对神经元起保护作用。

Research on cerebral ischemia/reperfusion-induced denitrosylation of nNOS in the hippocampal CA1 region of rats

Objective To investigate the denitrosylation of nNOS induced by cerebral ischemia /reperfusion on the apoptosis in the hippocampus CA 1 region of rats .Methods Transient cerebral ischemia for 15 min was performed in SD rats.The rats were randomly divided into 4 groups：sham group （S group）, ischemia/reperfusion group （I/R group）, unilateral intracerebroventricular injections of GSNO , 7-NI, MK801, NS102 and GYKI after ischemia/reperfusion groups （GSNO group, 7-NI group, MK801 grouop, NS102 group, and GYKI group）, unilateral intracerebroventricular injections 10%DMSO or saline groups （ DMSO group and saline group ） .The rat model of cerebral ischemia/reperfusion was established by 4-vessel occlusion method .S-nitrosylation was detected by the biotin -switch assay.SDS-PAGE, immunoblotting and Cresyl violet staining were used to study the levels of denitrosylation of nNOS and the injury of the rat hippocampal neurons .Results The denitrosylation of nNOS was significantly noticeable in the I /R group than in the S group （P〈0.05）.The S-nitrosylation of nNOS was lightly observed in the GSNO group , 7-NI group and MK801 group than in the I/R group （P〈0.05）, meanwhile the GYKI group, NS102 group, DMSO group, and saline group were almost the same with I/R group.Conclusion The denitrosylation of nNOS plays an important role in the cell apop-tosis induced by I/R in the hippocampal CA 1 region of rats .