【摘要】 目的研究大鼠视网膜缺血-再灌注损伤中的超微结构改变以及凋亡相关基因表达的变化,探讨其损伤机制。方法将28只大鼠随机分为正常组和手术组,手术组按照再灌注后不同时间段分为1h、6h、12h、24h、48h、72h组。前房加压法制作大鼠视网膜缺血-再灌注损伤模型,透射电镜检测视网膜超微结构改变,免疫组织化学法检测视网膜组织中bcl-2、bax、Fas的表达。结果(1)正常组视网膜神经纤维中微管及线粒体清晰可见;视网膜神经节细胞(retinal ganglion cells,RGCs)核大,电子密度低,核仁明显,细胞器丰富;再灌注损伤后RGCs核膜肿胀,线粒体嵴模糊不清,可见凋亡小体,神经纤维中微管模糊、减少甚至消失,以再灌注后24h为甚;(2)再灌注后6h,bax表达逐渐递增,24h达到高峰,48h开始下降,72h不明显;(3)bcl-2在视网膜神经节细胞层、纤维层及内核层有微弱表达,各个时间段变化不明显;(4)Fas表达改变与bax基本一致。结论视网膜缺血-再灌注损伤中,细胞凋亡是引起视网膜内核层和神经节细胞层细胞死亡的主要方式,其损伤机制与凋亡相关基因bcl-2、bax、Fas的表达变化有关。更多还原

【Abstract】 Objective To investigate the mechanism of rat retinal ischemia-reperfusion injury by detecting the changes of ultrastructure and expression of apoptosis related genes.Methods A total of 28 rats were divided into normal and operation groups.The latter were subdivided into 1st,6th,12th,24th,48th and 72th hours after reperfusion groups.The models of retinal ischemia-reperfusion injury was established by transient elevating introcular pressure.The retinal ultrastructure changes were detected by electron microscope and the expressions of bax,bcl-2 and Fas were studied by strept avidin-biotin complex (SABC) immunohistochemistry.Results (1)At 24th hour after reperfusion the apoptotic body came out in ultrastructure of retinal cell detcted by electron microscope;(2) Bax positive cells were observed in 6th hour after transient ischemia,and the number of positive cells peaked at 24th hour after ischemia,then was decreased at 48th hour,and bax expression peaked in 24th and 48th hours in GCL and INL of retina;(3)Bcl-2 showed weak expression and no significant changes after ischemia;(4)Similarly to bax,Fas expression was gradually increased as early as 6th hour,peaked at 24th hour,then was decreased at 48th hour.Conclusion Apoptosis may play a vital role in retinal cells death at nucler cells layer and ganglion cells layer in retinal ischemia-reperfusion injury.The mechanism of retinal ischemia-reperfusion injury is involved in the expression of apoptosis related genes,such as bax and Fas.更多还原