银杏叶提取物对豚鼠视神经横断伤后视网膜神经节细胞结构及功能的保护作用

目的： 探讨腹腔注射银杏叶提取物（Ginkgo biboba extract，EGb 761）对豚鼠视神经横断伤后视网膜神经节细胞（retinal ganglion cell, RGC）形态及功能的保护作用。方法： 75只白化豚鼠随机等分为正常对照组、假手术组、模型组、生理盐水组和EGb 761组。分离暴露豚鼠的右眼视神经并于球后1.0 mm处进行横断造模，正常对照组不作任何处理，假手术组仅分离暴露视神经。生理盐水组和EGb 761组分别于实验开始前1周每日腹腔注射1次相应体积生理盐水和EGb 761（100 mg/kg），术后继续给药4周。术后第4天，各组随机处死3只豚鼠，采用脱氧核苷酸转移酶介导的dUTP缺口末端标记（terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labeling, TUNEL）法检测RGC凋亡；分别于术后第14和28天进行图形视网膜电图（pattern electoretinogram, PERG）检查；摘取眼球作组织病理学检查并计数视网膜垂直经线RGC数目。结果： 术后第4天，正常对照组、假手术组和EGb 761组均未见TUNEL阳性RGC，模型组和生理盐水组均见有TUNEL阳性RGC。术后第14和28天，模型组和生理盐水组RGC数目均少于正常对照组和假手术组（P〈0.05），EGb 761组少于正常对照组和假手术组（P〈0.05），但显著多于模型组和生理盐水组（P〈0.05）；术后第14和28天，EGb 761组PERG的N95振幅较模型组和生理盐水组高（P〈0.05），与模型组和假手术组相近（P〉0.05）。RGC数目与N95振幅呈正相关（r=0.859, P=0.001 5）。结论： 腹腔注射银杏叶提取物EGb 761能抑制豚鼠视神经横断后的RGC凋亡，对RGC的结构和功能具有保护作用。

Protective effects of Ginkgo biloba extract on morphology and function of retinal ganglion cells after optic nerve transection in guinea pigs

Objective： To investigate the effects of Ginkgo biloba extract （EGb 761） on the morphology and function of retinal ganglion cells （RGC） in guinea pigs with optic nerve transection.
Methods： Seventy-five albino guinea pigs were randomly divided into five groups： normal control group, sham-operated group, untreated group, normal saline group and EGb 761 group. No operation was performed in the normal control group. Optic nerve was merely exposed in the sham-operated group, but transected at 1.0 mm from posterior pole of the eye ball in the untreated, normal saline and EGb 761 groups. Guinea pigs in the EGb 761 group or the normal saline group received daily intraperitoneal injection of EGb 761 （100 mg/kg） or corresponding volume of normal saline from 7 days before experiment to 28 days after experiment. Three guinea pigs in each group were sacrificed for apoptosis assay （TUNEL method） of RGC. Pattern electoretinograms （PERGs） were recorded 14 and 28 days after transection, respectively. At the end of the examination, six guinea pigs were killed for histological examination and RGC count.
Results： No TUNEL-positive cells were observed in the normal control, sham-operated and EGb 761 groups, but there were TUNEL-positive cells in the untreated group and the normal saline group. The numbers of RGCs in the untreated and normal saline groups were less than those in the normal control and sham-operated groups at 14 days or 28 days （P〈0.05）. Although the number of RGCs in the EGb 761 group was less than those in the normal control and sham-operated groups （P〈0.05）, it was more than those in the untreated and normal saline groups （P〈0.05）. N95 amplitude in EGb 761 group was higher than those in the untreated and normal saline groups （P〈0.05） and close to those in the normal control and sham-operated groups （P〉0.05） at 14 days or 28 days. The number of RGCs was positive correlated to N95 amplitude （r=0.859, P=0.001 5）.
Conclusion： EGb 761 can inhibit the apoptosis of RGCs in guinea pigs after optic nerve transection, thus protect the morphology and function of RGCs.