α-硫辛酸对小鼠视网膜光损伤的保护作用

Protective Effect of α-Lipoic Acid Against Light-induced Retinal Damage in Mouse.

目的观察α-硫辛酸对光损伤后小鼠视网膜的保护作用。方法将42只成年健康BALB/C小鼠随机分为正常组、光损伤组和药物干预Ⅰ组和药物干预Ⅱ组,药物干预Ⅰ组造模前后均给药,药物干预Ⅱ组造模后给药。药物干预组腹腔注射α-硫辛酸注射液100mg/kg,1次/日,直至处死。用光损伤装置建立小鼠视网膜光损伤模型,光照时间为12h,之后暗室饲养12h,共3个循环,总光照时间为36h。各组动物分别于7天及14天处死并摘取眼球,常规方法制备眼球石蜡切片,在光学显微镜下观察视网膜组织病理学变化,同时测量视网膜外核层厚度,计数外核层细胞凋亡数及凋亡指数。结果药物干预组视网膜结构与光损伤组相比较,其层次更加分明,细胞排列较整齐,感光细胞层呈毛刷状,可见内外节交界。视网膜外核层厚度在正常组为41.62±0.77μm,在光损伤组7天时为30.51±0.73μm,14天时为20.04±0.52μm,药物干预Ⅰ组在7天时为40.52±0.80μm,14天时为41.23±0.72μm,药物干预Ⅱ组在7天时为31.70±0.70μm,14天时为38.92±1.43μm,经统计学分析,药物干预组视网膜外核层厚度值显著高于光损伤组,但尚不及正常组,组间具有显著性差异(P<0.001)。TUNEL试剂盒检测4组视网膜细胞凋亡结果显示:药物干预Ⅰ组和Ⅱ组小鼠的视网膜外核层凋亡细胞数及凋亡指数AI明显低于光损伤组,但不及正常组,组间具有统计学差异。结论本实验结果显示,α-硫辛酸对小鼠视网膜光损伤具有保护作用。

Objective To investigate the effect of α-lipoic acid on retinal damage in mouse.Methods Foutrty-two BALB/C mouse were randomly divided into 4 groups： normal control,model control,drug-treatment group（group1：throughout operation;group2：after operation）.The mice except normal control group were exposed to intermittent white light in a trunk with 12h dark adaptation and 12h light exposion at the light power of 21400±1600 LX and the temperature between 25～29℃.The mice in drug-treatment group were given α-lipoic acid via intraperitoneal injection with dose of 100mg/kg.The mice were respectively killed after 7 and 14 days.The eyes were removed and were processed to paraffin section for microscopy and TUNEL staining.Then the morphological changes were observed and analyzed with optical microscope.The thickness of the outer nuclear layer（ONL thickness） was measured.And we counted the number of apoptotic photoreceptors to compare the effect of α-lipoic acid on light-damage of retina.The mean and standard deviation were calculated and analyzed with analysis of variance.Results Compared with the model-control group,the mice in drug-treatment group had more clearly demarcated retina structure and more ordered cells,and the outer nuclear layer retinal cells and the photoreceptor cells were swelling but had normal morphology.TUNEL assay showed large amount of TUNEL positive cells in ONL in the model control,and the number of TUNEL positive cells in the treatment group were reduced.We found that the ONL thickness（10×10times） of the mice of normal control group was 41.62±0.77μm,and the ONL thickness of the mice of model control group was 30.51±0.73μm for 7 days,and 20.04±0.52μm for 14 days.And in the drug-treatment group,the ONL thickness was 40.52±0.80μm in group C1 for 7 days,and 41.23±0.72μm for 14 days.In group C2,the ONL thickness was 31.07±0.70μm for 7 days,and 38.92±1.43μm for 14 days,which was significantly（P〈0.001） higher than those of the rats in model control group.The statistics showed that the thickness of ONL and AI had statistical significance between the four groups.Conclusion In the experiment conditions,the effect of α-lipoic acid on retina light damage was significant,which can protect and rescue the retina and inhibit pathological cells apoptosis after retinal photochemical damage.