Peroxiredoxin6在糖尿病大鼠视网膜中的表达

摘要

背景研究表明氧化损伤在糖尿病并发症的发生发展中发挥着重要的作用,Peroxiredoxin 6(Prx6)是双功能的蛋白质,其清除磷脂氢过氧化物的活性非常重要,因为细胞质中普遍存在的谷胱甘肽过氧化物酶(GPx1)无此功能.目的观察Prx6在实验性糖尿病大鼠视网膜中的表达,分析随着糖尿病病程的延长其在视网膜的表达情况.方法 Wistar大鼠60只,随机分为正常对照组12只和糖尿病组48只.糖尿病组腹腔注射链脲佐菌素(STZ)65 mg/kg诱发糖尿病,将造模成功的大鼠随机分为糖尿病1、2、3个月组,每组16只.于各时间点处死大鼠,采用逆转录-聚合酶链反应(RT-PCR)和免疫组织化学法分析Prx6在不同时间点糖尿病组大鼠视网膜中的表达,应用Image-Pro Plus 6.0图像分析软件测定阳性反应强度,即平均吸光度(A)值.结果免疫组织化学染色结果显示,正常对照组大鼠视网膜内外颗粒层及视网膜、脉络膜血管均有Prx6蛋白的表达,视网膜神经节细胞(RGCs)层有少量Prx6蛋白的表达,表达于细胞质;糖尿病1个月组大鼠视网膜内外颗粒层棕黄色阳性染色细胞增多;2个月组、3个月组大鼠视网膜各层Prx6蛋白的表达均为阴性,各组间总体比较差异均有统计学意义(F=22 967.63,P＜0.05).RT-PCR结果显示,正常对照组大鼠视网膜有Prx6 mRNA的表达;糖尿病1个月组视网膜Prx6 mRNA表达增高;2个月组Prx6 mRNA表达量明显降低,仅有少量表达;3个月组表达阴性,各组间总体比较差异均有统计学意义(F=942.84,P＜0.05).结论Prx6作为一种抗氧化蛋白存在于视网膜中,可保护组织细胞免受活性氧簇、氧自由基等的损害,随着糖尿病病程的延长,Prx6在视网膜组织和细胞中的表达量逐渐降低,直至消失.%Background Oxidative stress plays an important role in the pathogenesis of diabetic complications.Peroxiredoxin 6(Prx6) is a doubly-functional protein.and its ability to eliminate phospholipid hydroperoxides is essential. Objective The aim of this study was to investigate the dynamic expression of Prx6 in the retina of streptozotocin(STZ)-induced diabetes and explore its correlation with the progression of diabetic retinopathy. Methods Diabetes was induced by an intraperitoneal injection of streptozotocin(STZ)in 48 clean Wistar rats.The rats were sacrificed at 1,2,and 4 months after the injection of STZ,and expressions of Prx6 protein and Prx6 mRNA in the retina was determined by immunohistochemistry and reverse transcription polymerase chain reaction.Another 12 matched normal Wistar rats were used as the control group. Results The resuh of immunohistochemistry showed that Prx6 protein was expressed in the cytoplasm of the outer nuclear layer(ONL)and inner nuclear layer(INL)in normal rats,and low expression of Prx6 protein was observed in the ganglion cell layer (GCL).In the first month,Prx6 protein was strongly expressed in the INL and the ONL of diabetic rats.However.two and three months after STZ administration,the expression of Prx6 protein was absent in the retina,showing a considerable difference among different course groups(F=22 967.63,P＜0.05).Furthermore,the expression trend of Prx6 mRNA in the retina was similar to that of the Prx6 protein with a significant difference among different course groups(F=942.84,P＜0.05). Conclusion It is conceivable that normal maintenance of Prx6 expression may be important to the prevention of diabetic retinopathy.We hypothesize that oxidative impairments in the retina that develop over time may partly contribute towards the development of retinal dysfunction,which eventually leads to retinal degeneration during the progressive phase of STZ-induced diabetes in adult rats.