牛磺酸对糖尿病大鼠视网膜神经胶质原纤维酸性蛋白mRNA及其蛋白表达的影响

背景:糖尿病视网膜病变是糖尿病普通的并发症,牛磺酸是视网膜中含量最丰富的游离氨基酸,它是视网膜再生和发育必需的营养因子,缺乏牛磺酸会引起视网膜结构和功能改变。目的:探讨牛磺酸对糖尿病大鼠视网膜神经胶质原纤维酸性蛋白mR-NA及其蛋白表达的影响。设计:随机对照观察。单位:中国人民解放军第三军医大学。材料:试验于2003-3/2003-12在第三军医大学完成。选取封闭群SD大鼠54只,体质量为250g。将造模成功的糖尿病大鼠54只随机分为糖尿病1月组、牛磺酸干预糖尿病1月组、糖尿病2月组、牛磺酸干预糖尿病2月组、糖尿病3月组和牛磺酸干预糖尿病3月组6组,每组9只。同期选取正常对照组共15只。方法:动物单笼喂养,自由进食饮水,实验前禁食12h,用链脲佐菌素诱导糖尿病,用尿糖试纸测尿糖达( )以上,尾靜脉采血测血糖浓度大于16.7mmol/L即为模型建立成功。采用免疫组化、RT-PCR和Westernblotting等技术方法,检测神经胶质原纤维酸性蛋白mRNA和蛋白的表达。观察牛磺酸对糖尿病视网膜病变大鼠神经元及神经胶质细胞的影响。主要观察指标:观察神经胶质原纤维酸性蛋白mRNA和蛋白表达。结果:①免疫组化分析显示:糖尿病大鼠1个月时,牛磺酸即可抑制神经胶质原纤维酸性蛋白的免疫反应性,随着牛磺酸干预时间的延长,神经胶质原纤维酸性蛋白免疫反应性渐弱。②RT-PCR检测:2个月始,糖尿病组神经胶质原纤维酸性蛋白mRNA的表达开始增大,牛磺酸明显下调神经胶质原纤维酸性蛋白mRNA的表达。③3个月的糖尿病组神经胶质原纤维酸性蛋白蛋白表达最强。牛磺酸干预糖尿病大鼠2个月时,神经胶质原纤维酸性蛋白表达减少。结论:牛磺酸可下调神经胶质原纤维酸性蛋白及mRNA表达,对糖尿病视网膜病变具有保护作用。

Effect of taurine on the expression of retinal glial fibrillary acidic protein mRNA and its protein in rats with diabetes mellitus

BACKGROUND: Diabetic retinopathy is the common complications of diabetes mellitus. Taurine is free aminoacid with the mostly abundant content in retina, and it is the necessary nutrition factor for regeneration and development of retina. Deficiency of taurine will cause structural and functional change of retina.OBJECTIVE: To probe into the effect of taurine on the expression of retinal glial fibrillary acidic protein (GFAP) mRNA DESIGN: A randomized and controlled observation SETTING: Third Military Medical University of Chinese PLA MATERIALS: This experiment was carried out at the Third Military Medical University of Chinese PLA from March 2003 to December 2003.Totally 54 closed group SD rats, with body mass of 250 g, were chosen.The successful diabetic rat model were randomly divided into 6 groups: diabetic group of 1 month, taurine-treated diabetic group of 1 month, diabetic group of 2 months, taurine-treated diabetic group of 2 months, diabetic group of 3 months, taurine-treated diabetic group of 3 months, with 9 rats in each group. Another 15 rats were chosen homeochronously as normal control group.METHODS: The animals were raised in separate cages. They were free to access to food and water, and fasted for 12 hours before experiment. Streptozotocin was used to induce diabetes mellitus .When Tes-Tape showed urine glucose reached more than (+++), and blood glucose concentration of venous blood from tail measured ＞16.7 mmol/L, models were established successfully. Expressions of GFAP mRNA and protein were measured with immunohistochemistry, RT-PCR, Western blotting and other technical methods. The effect of taurine on retinal neurons and glial cells in rats with diabetes mellitus was observed.MAIN OUTCOME MEASURES: Expressions of GFAP mRNA and protein RESULTS: ① Immunohistochemical analysis showed that: When rats suffered from diabetes mellitus for 1 month, taurine can inhibit the immunoreactivity of GFAP. With the elongation of intervention time of taurine, the immunoreactivity of GFAP is weakened. ②RT-PCR detection: Starting from the beginning of 2 months, the expression of GFAPmRNA in diabetic group began to increase; taurine obviously down-regulated the expression of GFAP mRNA. ③ In taurine-treated diabetic group of 3 months,the expression of GFAP was the strongest. When diabetic rats were treated by taurine for 2 months, the expression of GFAP was decreased.CONCLUSION: Taurine can down-regulate the expression of GFAP mR-NA and protein, indicating that it can protect retinal pathological change in rats with diabetes mellitus.