缺血再灌注大鼠视网膜诱导型一氧化氮合酶与细胞凋亡的研究

Experimental study of inducible nitric oxide synthase and apoptosis in rats' ret inal ischemia-reperfusion injury

目的 探讨缺血再灌注大鼠视网膜诱导型一氧化氮合酶 (induciblenitricoxidesynthase ,iNOS)的表达、视网膜细胞凋亡的发生以及二者之间的关系。 方法 采用前房灌注生理盐水的方法制作实验性视网膜缺血再灌注损伤模型 ,分别于再灌注不同时间点取材 ,行免疫组织化学法染色iNOS阳性细胞 ;TUNEL法检测视网膜凋亡细胞 ;透射电镜观察视网膜超微结构。结果 缺血再灌注早期 ,视网膜主要表现为内层水肿增厚 ,晚期主要表现为视网膜萎缩变薄、神经节细胞减少。缺血再灌注 3h组视网膜神经节细胞层及内核层细胞出现iNOS弱阳性表达 ,12h组阳性表达达高峰 ,与其余各组比较差异有显著意义 (P <0 .0 1) ,2 4、4 8h组iNOS表达渐减少。视网膜组织细胞凋亡见于缺血再灌注 12、2 4及 4 8h组 ,凋亡细胞主要位于内核层 ,且 2 4h组凋亡阳性表达最强 ,与其他各组比较差异有显著意义 (P <0 .0 1)。结论 缺血再灌注大鼠视网膜iNOS表达增加 ,介导视网膜缺血再灌注损伤 ;视网膜细胞的损伤部分以凋亡的形式发生 ,iNOS的表达可能对细胞凋亡的发生起一定的诱导作用。

Objective To investigate the expression of inducible nitric oxide synthase (iNOS), apoptosis of retinal cells and the role of iNOS in apoptosis in rats' retinal ischemia-reperfusion injury. Methods The rat model of experimenta l retinal ischemia-reperfusion injury was created by increasing the intraocular pressure. At different times post ischemia, the immunohistochemical staining an d TUNEL method were taken. The retinal ultrastructural morphological changes wer e observed by the transmission electron microscope. Results The inner retinal la yers of early groups swelled evidently, and those of the subsequent groups becam e atrophy and the count of retinal ganglion cells decreased. iNOS was weakly exp ressed in the cytoplasm of cells of retinal ganglion layer and inner nuclear lay er at the 3rd hour post ischemia. The expression attained the highest level at t he 12th hour after ischemia, which had a significant difference with other group s(P<0.01), then the expression was declined. The apoptotic cells were mainly in inner nuclear layer and could be seen at the 12th, 24th and 48th hour post i schemia, the peak was the group of 24 hours(P<0.01). Conclusion After ischemia-reperfu sion, the expression of iNOS in the rat retina was greatly enhanced,which involv ed the injury of retinal ischemia-reperfusion; The injury of reinal neurons wa s occurred in the form of apoptosis partly.The expression of iNOS may has an ind ucible role on cell apoptosis.