银杏内酯B对N-甲基-N-亚硝脲诱导的大鼠视网膜变性的保护作用

Protective effect of Ginkgolide B on N-methyl-N-nitrosourea induced retinal degeneration in rat

目的观察不同剂量的银杏内酯B(GB)对N-甲基-N-亚硝脲(MNU)诱导的SD大鼠视网膜变性的保护作用。方法取出生后46d的SD大鼠86只,随机抽取6只为正常对照组;80只分为4大组,每组20只。随机分为模型对照组,GB大、中、小剂量组。各组每次4只分别于24h、48h、3、5、7d行右眼闪光视网膜电图(ERG)检查,并通过视网膜形态学分析测量中心视网膜的外视网膜厚度。结果ERG正常组a波振幅为(105·4±16·8)μV,b波振幅为(292·6±19·6)μV。模型对照组24h后,a波消失。GB各剂量治疗组a波消失时间分别为2、3、3d,小、中剂量组b波消失时间分别为5d和7d,大剂量组7d时b波振幅下降为正常的8%。中心视网膜厚度检查:正常组大鼠中心视网膜的外视网膜厚度为(98·4±1·8)μm。MNU处理7d模型对照组外视网膜厚度为(17·8±2·1)μm,而GB各剂量治疗组分别为(25·2±2·7)、(38·3±2·3)、(45·8±2·3)μm。结论GB对MNU诱导的实验性大鼠视网膜变性所致的大鼠视网膜光感受器细胞损伤和视功能损害具有保护作用,并且这种作用呈剂量依赖性。

Objective Some active principles of Chinese herbal medicine such as ginkgolide can effectively prevent the neurons from damage and apoptosis. This study was to investigate the protective effect and the mechanism of action of ginkgolide B on retinal degenerative diseases induced by N-methyl-N-nitrosourea （MNU） in rats. Methods Eighty-six 46-day-old SD rats were randomly divided into normal control group （6 rats）, model control group （20 rats） and Ginkgolide B group. Retinal degeneration model was created by the intraperitoneal injection of 40 mg/kg MNU. The rats in Ginkgolide B group received intraperitoneal injection of different dose（20,40,60 mg/kg） of Ginkgolide B （20 rats each dose group） 3 days before injection of MNU. Electroretinogram（ERG） examination was recorded at 1 day,2,3,5 and 7 days after modeling for the assessment of retinal function of rats. The thickness of central retina were measured by HE coloration. Results The a-wave and b-wave amplitudes of flash ERG in normal control group were （ 105.4 ± 16. 8 ） μV and （ 292. 6 ± 19.6） μV, however, those in the model control group were undetectable at day 1 and day 2 after injection of MNU respectively,while a-wave vanished at 2,3 and 3 days in large,middle and small dose of Ginkgolide B group and b-wave vanished at 5 days and 7 days in middle and small dose Ginkgolide B group after modeling respectively. Amplitude of b-wave reduced to 8% in large dose of Ginkgolide B group compared with normal rats at 7 days. The mean thickness of central retina in normal rats was （98.4 ± 1.8）μm, and was （ 17. 8 ：t： 2. 1 ） μm in model control group and （25.2 ± 2. 7 ） μm, （ 38. 3 ± 2. 3 ） μm, （45.8 ± 2. 3 ） μm in large, middle and small dose of Ginkgolide B group respectively at 7 days. Conclusion Ginkgolide B can effectively suppress MNU-induced retinal damage in a dose-dependent manner.