蛇毒神经生长因子对大鼠视网膜缺血再灌注损伤超微结构的影响

Effects of venom nerve growth factor on the retinal ultrastructure after retinal ischemia reperfusion injury in rats

目的探讨玻璃体内注射蛇毒神经生长因子(venom nerve growth factor,vNGF)对实验性大鼠视网膜缺血再灌注(retinal ischemia reperfusion,RIR)损伤的视网膜超微结构是否具有保护作用。方法采用升高眼压的方法制作实验性RIR损伤大鼠模型。将Spregue-Dawley(SD)大鼠随机分为正常组、缺血组、实验组及对照组。实验组及对照组于再灌注开始时分别注入vNGF和平衡盐溶液各20μL。通过透射电镜观察各组大鼠视网膜超微结构变化。结果缺血组主要是视网膜神经节细胞(retinal ganglion cells,RGCs)和光感受器细胞等结构的水肿。对照组再灌注后1d出现膜盘排列紊乱、变形,RGCs核染色质浓缩、边集、变性,胞浆内细胞器肿胀、空泡化且大量减少。神经纤维内大量的线粒体肿胀、空泡化。至再灌注后7d膜盘溶解,RGCs出现变性坏死及凋亡;而实验组于再灌注后1d主要为光感受器细胞排列紊乱、肿胀及RGCs肿胀、少许变性为主,至再灌注后7d膜盘排列尚整齐,细胞肿胀减轻,胞浆内细胞器较丰富。实验组大鼠视网膜超微结构的改变较对照组明显轻。结论大鼠玻璃体内注射vNGF对实验性RIR损伤大鼠的视网膜超微结构具有保护作用。

Objective To evaluate the protecting effects of venom nerve growth factor（vNGF） injected into the vitreous cavity on the retinal ultrastructure after experimental retinal ischemia reperfusion （RIR） injury in rats. Methods The rat model of experimental RIR injury was made by increasing the intraocular pressure. The Spregue-Dawley（SD） rats were randomly divided into normal, ischemia, experimental and control groups. At the beginning of reperfusion,20 μL（ 100 BU） of vNGF was injected into the vitreous cavity of experimental group,and 20 μL of balanced salt solution was injected into the vitreous cavity of control group,respectively. The ultrastructural morphology was examined under transmission electron microscope. Results In the ischemia group, the chondriosomes of retinal ganglion cells （ RGCs ） and photoreceptor swelled slightly. At one day after reperfusion of control group, the arrangement of the membranes disc became disordered and distorted ;The chromatin of RGCs concentrated, closed to nuclear membranes, and denaturalized; Most chondriosomes of retinal nerve fiber layer swelled and were vacuolating; Organelles in the cytoplast were swelling, vacuolating, and decreasing. At seven days after reperfusion of control group, the membranes disc became dissolving;RGCs were necrosis and apoptosis. While in the experimental group,at one day after reperfusion, RGCs and photoreceptor swelled and denaturalized slightly. At seven days after reperfusion, the arrangement of the membranes disc tidied, the swell of RGCs lightened,and organelles in the cytoplast were abundant. The changes of rat retinal ultrastructural morphology in the experimental group were better than those in the control group. Conclusion Injection of vNGF into the vitreous cavity has the protecting effect on the retinal ultrastructure after experimental RIR injury rats.