激活素A及其结合蛋白在STZ损伤小鼠胰腺组织中的表达及意义

Expressions of activin A and its binding protein follistatin in pancreatic tissues of streptozotocin-induced diabetic mice and their significances

目的:探讨激活素A(ActA)及其结合蛋白follistatin(FS)在小鼠胰腺损伤过程中的表达,为胰腺损伤后组织修复与重建奠定基础。方法:雄性ICR小鼠21只,随机分为对照组(n=6)与实验组(n=15)。应用一次性大剂量腹腔注射链脲菌素(STZ)制备小鼠胰岛损伤模型,免疫组织化学染色法检测ActA和FS蛋白表达,逆转录聚合酶链反应(RT-PCR)法检测ActA和FS mRNA相对转录水平。结果:免疫组织化学染色显示,ActA主要分布在正常小鼠胰岛细胞,腺泡细胞也有表达;FS仅表达在小鼠胰岛细胞,在腺泡细胞不表达。RT-PCR检测结果显示,ActA和FS mRNA均在正常小鼠胰腺组织表达,与对照组比较,实验组小鼠Act mRNA表达随着诱导时间的延长表达量进行性减少(P<0.01),而FS mRNA在诱导的第7天表达明显增加,第14和21天下降(P<0.01)。结论:ActA及FS主要表达在小鼠胰岛组织,在STZ诱导胰腺损伤过程中Act-FS系统表达失平衡,可能与糖尿病的发生、发展有关。

Objective To investigate the expressions of activin A （Act A） and its binding protein follistatin （FS） in mice with pancreatic injury and lay a fundation for tissue repair and reestablishment after pancreas injury. Methods Twenty one male ICR mices were randomly divided into two groups ： experimental group （n=15） and control group（n=6）, Mice were treated intraperitoneally with streptozotocin （STZ） to induce pancreatic injury. The expressions of Act A and FS protein were detected by immunohistochemistry, and the expressions of activin A and follistatin mRNA were examined by RT-PCR. Results In normal mice, Act A protein mainly distributed in islet cells, and also distributed in pancreatic acinar cells; FS protein only expressed in islet cells and not in acinar cells. Act A and FS mRNA expressed in pancreatic tissues. Compared with control group, the expression of Act A mRNA in mice in experimental group decreased gradually （P〈0.01）, the expression of FS mRNA increased at the 7th day after injury, then decreased gradually at the 14th and 21st day （P〈0.01）. Oonclusion Act A and its binding protein FS mainly express in mouse islet tissues. The unbalance of activin Act-FS system in streptozotocin-induced pancreatic injury may be involved in the pathogenesis of diabetes mellitus.