实验性视网膜脱离时神经生长因子对视网膜的保护作用

目的　研究神经生长因子 (nervegrowthfactor,NGF)在实验性视网膜脱离 (retinaldetachment,RD)时对视网膜神经细胞的保护作用。方法　 31只Spregue Dawley(SD)大鼠 (6 2只眼 )视网膜下注射透明质酸钠建立RD模型 ,分为 4个组 :NGF实验组 (2 1只眼 )、实验对照组 (2 1只眼 )、病理对照组 (14只眼 )和正常对照组 (6只眼 )。 2 1只SD大鼠右眼玻璃体腔内注射NGF 5 μl(浓度为 1g/L ,1次 / 4d) ,作为NGF实验组 ,左眼注射空白载体作为实验对照组 ,不用药物的 7只SD大鼠 (14只眼 )作为病理对照组。分别在建立RD模型后 12h ,1、2、4、8、16及 32d行光镜和电镜检查 ,进行形态学和细胞数目比较。结果　RD发生后NGF实验组和实验对照组视网膜可见光感受器细胞内、外节缺失、内外核层排列紊乱、神经细胞和神经纤维层水肿变性。实验对照组和病理对照组在镜下表现无明显差异 ,NGF实验组、实验对照组与病理对照组视网膜在RD后 1d镜下即产生明显差异 ,病变程度明显轻于病理对照组和实验对照组 ,以光感受器细胞的内、外节改变最为明显。当RD复位后 ,NGF实验组视网膜组织和细胞结构明显优于病理对照组和实验对照组。细胞计数结果显示 ,随着RD时间延长 ,视网膜细胞核数进行性下降 ,即使视网膜复位 ,各组细胞数仍少于正常对照

Neuroprotection of nerve growth factor in experiment retinal detachment

OBJECTIVE: To study the neuroprotection by nerve growth factor (NGF) in retina in experimental retinal detachment (RD). METHODS: Thirty one Sprague-Dawley rats were used as RD animal model by injected 0.1% sodium hyaluronate into the sub-neuroretina space. Those rats were divided into NGF experimental group, placebo group, normal control groups and pathologic control group. NGF 1 g/L/eye was injected into vitreous every 4 days in NGF experimental group and 5 micro l of PBS intravitreal injection was used as control after RD. On postoperative time 1/2 d, 1 d, 2 d, 4 d, 8 d, 16 d, 32 d, rats were sacrificed and eyes were enucleated. The effect of NGF on retina was assessed by electron, light microscopy and cell counters. RESULTS: Histology studies showed markedly changes in photoreceptor cells, bipolar cells and ganglion cells after RD, included depletion and shorten of inner and outer segments, disturbance and thinness of inner and outer nuclear layer and swelling of ganglion cells in NGF treated group and control. Changes in the microscopic examination in NGF group showed significantly less than that in control groups, especially in inner and outer segments of photoreceptor cells. In reattached retina, the tissue structure and cell morphology showed more close to normal in NGF group than that in RD control groups. Cell counters showed the cell numbers decreased both in NGF groups and RD control groups. When retina reattached, the cell number in experimental groups showed significantly lower than that in normal control group (P < 0.05). Nuclear number of outernuclear layer and ganglion cell layer in NGF groups was greater than that in RD control groups (P < 0.05). CONCLUSION: Intravitreal injection exogenous NGF partly protects retinal cells from degeneration in experimental RD and help recovery of retinal cells after retina reattached.