神经生长因子对糖尿病大鼠神经视网膜超微结构的影响

目的:通过观测实验性糖尿病动物的神经视网膜的超微结构变化,从视网膜的神经功能角度来探讨糖尿病视网膜病变的发生机制以及相关药物干预后的影响作用。方法:用链脲佐菌素制作糖尿病大鼠动物模型,分为正常对照组(CON组)、糖尿病对照组(DM组)、糖尿病神经生长因子治疗组(D+N组)。分别于病程3,6,9,12mo取大鼠眼球制备石蜡切片,将视网膜组织行HE染色,并将上述标本制备超薄切片,用透射电镜观察并分析。结果:从病程3mo开始,DM组视网膜血管内皮细胞及周细胞的核变形、线粒体肿胀变性、基底膜增厚。视神经节细胞水肿,胞器减少,线粒体变性。光感受器细胞(视锥、视杆)膜盘间隙扩大,线粒体及核也有病理改变。上述病变随病程延长而逐渐加重。经过NGF治疗后,上述DM改变有所减轻,主要表现在感光细胞外节膜盘间隙较DM组缩小,平行度好转;神经细胞突起水肿减轻,胞器水肿好转。各组DM大鼠的视网膜血管、神经网膜及视神经的糖尿病性病变之间未见明显的先后因果关系。结论:神经生长因子对DM大鼠视网膜形态学上所见的视网膜血管、感光细胞和神经节细胞的超微结构改变有着明确的改善作用。在DR的发病过程中,视网膜血管的病变与视网膜神经组织的病变可能是同时存在、互相促进,共同造成糖尿病视网膜病变和视功能的损害。

Effect of nerve growth factor on the ultrastructural changes of neurosensory retina in diabetic rats

AIM: To observe the ultrastructural changes of retina of diabetic rats and explore the forming mechanism of experimental DR from the aspect of retinal vassles and neurosensory retina, and further to investigate the theraputic effects of some drugs such as nerve growth factor (NGF).·METHODS: Diabetes was induced in 96 adult male Wistar rats with a single dose of 45 mg/kg of streptozotocin (STZ) administered intravenously. Rats were divided into the 3 groups: normal control group (CON), diabetes control group (DM), NGF-treated group (D+N). Specimen was obtained at 3, 6, 9 and 12 months separately. Ultrathic sections were taken from the rats’ eyes and were observed under light microscope and transmission electron microscope.·RESULTS: The diabetic animal models which were induced by STZ in Wistar rats had a relatively high rate of success and steady process. At every experimental time point, there was significant difference between DM group and CON group (P<0.01). From the 3th month on, we observed that the nuclears of endothelial and pericytes cells in retina vessles were distorted, condrocyte swelled, basement membrane increased, retinal ganglion cell swelled, the condrocyte degenerated, membrane disk spaces of photoreceptors (rods and cone) were enlarged. All these pathological changes were getting worse gradually with the progression of DR.With the treatment of NGF, all the abnormalities were improved, such as the membrane disk spaces shrinked, neural cells processes were little swelled. We did not find the obvious causal relationships among the impairment of retinal vassles, neurosensory retina and optic nerve.·CONCLUSION: There were in some extent pathomor-phology changes in the retinal vessles, photoreceptors, ganglion cells. With the treatment of NGF, the path-omorphology changes show the theraputic effects on ganglion cells and neural cells. We can suppose that the changes of vassles and neurocells exist simultaneously and affect each other. This may lead to DR as well as the impariment of visual function.·