牛磺酸对大鼠视网膜光化学损伤的保护作用研究

Protective effects of taurine on retina photochemical damage in rats

目的 应用持续高强度光照条件下大鼠视网膜光化学损伤的模型,观察膳食中添加牛磺酸对大鼠视网膜中感光细胞的影响。方法 以白色荧光灯为光源,用(3 0 0 0±2 0 0 )lx的光照强度分别给予普通饲料组和4%牛磺酸饲料组SD大鼠2 4h持续光照,同时设立正常对照,测定视网膜电图,观察病理形态和超微结构变化,并测定视网膜中丙二醛(MDA)含量以及超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH px)活性。结果 光照后视网膜电图结果显示普通饲料组a波、b波幅值显著降低(P <0 0 1) ,潜伏时间延长(P <0 0 1) ,4%牛磺酸饲料组a波幅值下降(P <0 0 1) ,其它指标无明显变化;光照后普通饲料组视网膜内外节段排列紊乱,外核层变薄,内节线粒体肿胀,感光细胞核固缩,而牛磺酸添加组视网膜结构保持良好;光照后MDA含量在两组均显著增加,牛磺酸组比普通饲料组低(P <0 0 1) ,SOD、GSH px活性在光照组显著降低,而牛磺酸组虽有升高但无显著意义。结论 预防性喂饲牛磺酸能给予感光细胞一定的保护作用,其保护作用部分可能与牛磺酸的抗氧化以及自由基清除有关。

Objective To establish the animal model of photochemical damage and investigate the protective effects and mechanism of taurine on the retina photochemical damage in rats. Methods Fifty rats were randomly divided into normal control group, light damage group and 4% taurine supplementation group. After 15 day cyclic light and 24-hour dark adaptation, the last two groups were exposed to (3000±200) lx transmitted by six cold white lights. After 24-hour exposure, the rats were stayed in darkness. The retinal morphology was detected through light and electron microscope and the retinal function was detected by Scot-ERG. The concentration of MDA and the activity level of SOD/GSH-px were measured. Results In light damage group, the a and b amplitude (Aa/Ab) were significantly decreased, but in taurine group, except the decreased Aa, others were of no significant changes. The retina inner and outer segments were swollen and in disorder after exposure, the outer nuclear layer got thinner than that of control. The mitochondria in light damage group was swollen, but in taurine group changes were less significant. After exposure, the concentration of MDA in retina was markedly increased in light damage group and the activity level of SOD/GSH-px were decreased, but in taurine group MDA slightly increased and SOD/GSH-px was up-regulated but of no significance. Conclusion Dietary supplementation with 4% taurine partially protected photoreceptor from degeneration, which might correlate with the antioxidation and inhibition of free radical character of taurine.