依帕司他对糖尿病大鼠肾脏醛糖还原酶活性、细胞凋亡及超微结构的影响

Effects of epalrestat on aldose reductase activity,ultrastructural pathology and apoptosis in the renal tissues of diabetic rats

目的:研究醛糖还原酶(AR)、凋亡相关蛋白Bcl-2和Bax与糖尿病肾病的关系,探讨醛糖还原酶抑制剂(ARIs)依帕司他对糖尿病肾病的治疗作用。方法:雄性Wistar大鼠30只,随机平均分为3组:正常对照组、糖尿病模型组和依帕司他(10 mg.kg-1.d-1)治疗组,模型组和依帕司他组腹腔注射链脲佐菌素65 mg.kg-1诱发糖尿病。16周后,处死大鼠,分离晶体和肾脏,测定组织AR活性,观察Bcl-2和Bax的表达,取部分肾皮质电镜细胞计量、观察细胞凋亡的形态学变化。结果:与正常对照组相比,糖尿病模型组肾脏皮质AR活性明显升高(P<0.01),依帕司他治疗组AR活性明显较模型组降低(P<0.01),而血糖无明显变化。糖尿病模型组肾脏Bcl-2和Bax蛋白表达增加,依帕司他治疗组的Bcl-2蛋白表达较模型组增多,而Bax蛋白表达较模型组减少。透射电镜下见糖尿病模型组肾脏肾小管上皮细胞呈典型的凋亡形态学改变,依帕司他治疗组大鼠肾组织细胞凋亡改变明显减轻。糖尿病模型组肾小球基底膜增厚,系膜区域扩大,治疗组病变减轻。结论:AR过度激活可能通过促进Bcl-2和Bax蛋白的表达诱导细胞凋亡,而参与DN的发生与发展。依帕司他通过抑制醛糖还原酶活性,调节Bax和Bcl-2的表达抑制细胞凋亡,改善糖尿病大鼠肾脏结构与功能。

Objective： To study the relationship of aldose reductase and apoptosls-related protein Bcl-2 and Bax with diabetic nephropathy as well as the treatment of diabetic nephropathy with aldose reductase inhibitor epalrestat. Methods： 30 male Wistar rats were randomly assigned to one of three groups： healthy control, diabetic control, or diabetic rats treated with epalrestat 10 mg·kg^-1·d^-1. The diabetic module of the rats was set up by intraperitoneal injection of streptozotocin 65 mg·kg^-1. At the end of 16-week treatment, the rats were sacrificed under anesthesia to collect the len and renal tissues for measurements of aldose reductase activity and expression of Bcl-2 and Bax proteins. The morphological examination of the renal apoptotic cells was conducted by a cell count technique of the renal cortex with transmission electron microscope. Results： Compared to healthy control rats, the diabetic rats had higher tissue aldose reductase activities （P 〈0.01）. Epalrestat significantly reduced the tissue aldose reductase activities of diabetic rats （P 〈 0.01）. The diabetic rats had higher expression of the Bcl-2 and Bax proteins. Epalrestat-treated rats experienced an increase of the Bcl-2 protein expression but a decrease of Bax expression compared to the diabetic rats. The diabetic rats showed a typical apoptotic shape of renal tubular epithelial cell and hyperplasia of glomerular basement membrane and mesangial region. Epalrestat was seen to alleviate the worsen apoptotic and hyperplasic procedures. Conclusion： Epalrestat improved the renal pathological procedure and dysfunctions by inhibiting the aldose reductase activaties, and suppressed the apoptosis of the renal cells by modulating the expression of Bcl-2 and Bax proteins.