视网膜挫伤模型兔视神经细胞的凋亡

Apoptosis of optic nerve cells after retinal contusion injury in rabbits

背景:视网膜挫伤是眼外伤后导致视力损害的主要原因之一,临床治疗比较棘手。虽然对视网膜挫伤后眼底改变在临床上已有较充分的认识,但在其发病机制、药物治疗上意见仍不一致。目的:在兔视网膜挫伤模型上,观察视神经细胞的凋亡并探讨其发生机制。方法:健康成年无眼疾青紫蓝兔48只,随机分为8组,挫伤后1,3 h组、挫伤后1,3,7,14,28 d组及正常对照组,每组6只。右眼为致伤眼,以改良Allen’s重击法制备兔单眼挫伤性视网膜病变模型。分别于建立模型后在相应时间点获取兔眼标本,对筛板后5 mm视神经行病理切片,苏木精-伊红染色,观察组织形态并行神经胶质细胞计数,以电镜及TUNEL法观察视神经细胞凋亡情况。结果与结论:正常对照组兔视神经纤维排列整齐,胶质细胞与神经纤维走向一致,呈极性排列。挫伤后1,3 h、挫伤后1,3,7 d兔视神经纤维排列紊乱,胶质细胞杂乱无序。挫伤后1,3 h、挫伤后1,3,7,14,28 d胶质细胞计数减少,与正常对照组相比,差异有非常显著性意义(P<0.01)。视网膜挫伤后存在神经胶质细胞凋亡现象,正常对照组、挫伤后1 h、挫伤后28 d组几乎不见凋亡细胞;挫伤后3 h组、挫伤后1,3,7,14 d组均可见TUNEL染色阳性的凋亡细胞,其中在3 d组数量较多,与正常对照组之间比较,差异有非常显著性意义(P<0.01)。提示视网膜挫伤后,视神经胶质细胞凋亡可能是视功能恢复不良的原因之一。

BACKGROUND：Retinal contusion injury is one of the leading causes for vision impairment, and clinical treatment is difficult. Although fundus change after retinal contusion injury has been ful y understood, the pathogenesis and drug treatment stil remain controversial. OBJECTIVE：To explore the apoptosis and related mechanism of optic nerve cel s in rabbit model of retinal contusion injury. METHODS：Forty-eight healthy adult rabbits without oculopathy were divided into eight groups：1 hour, 3 hours, 1 day, 3 days, 7 days, 14 days, 28 days after contusion and normal control, with six rabbits in each group. Right eye of each rabbit was treated with Al en’s reformative hitting method as contusive retinopathy model. The eyebal s were enucleated at different time points after injury in rabbit retina. The pathological section of optic nerve 5 mm posterior to sieve plate was harvested. The morphologic changes of optic nerve were observed and number of glial cel s was measured using hematoxylin-eosin staining. Electron microscope and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling technique were used to assess apoptosis. c RESULTS AND CONCLUSION：In the normal control group, glial cel s presented cylinder shapes and neural fibers arranged neatly. The trend of the glial cel s was as the same as the neural fibers. But the optic nerve fibers arranged in disorder and the glial cel s lost polarity in the groups of 1 hour, 3 hours, 1 day, 3 days, 7 days after retinal contusion injury. The number of glial cel s in 1 hour, 3 hours, 1 day, 3 days, 7 days, 14 days, and 28 days was extremely significantly reduced compared with normal control group （P〈0.01）. There was cel apoptosis in＆amp;nbsp;optic nerve after retinal contusion injury, but almost not observed in optic nerve from normal control group, 1 hour and 28 days after injury. The apoptotic cel s were abundant at 3 hours, 1 day, 3 days, 7 days, 14 days after injury, and peaked at 3 days, showing extremely significant differences compared with normal control group （P〈0.01）. Apoptosis occurs in optic nerve after contusion of retina, which may be one of the reasons for incomplete recovery of retinal function.