| Objective To observe the effects of Irbesartan on the expression of mi R-93 and vascular endothelial growth factor(VEGF),fibronectin(FN)and Collagen IV(Col-IV)in the kidney of rats with type 2 diabetic nephropathy(T2DN)induced by streptozotocin(STZ),to explore the possible mechanism of renal protection by ARB drugs.Methods Male 10-week-old Wistar rats were randomly divided into three groups: normal control group(NC group),diabetic nephropathy model group(DN group)and Irbesartan treatment group(DN+I group),10 rats in each group.The rat model of DN was established by high-fat diet combined with intraperitoneal injection of low-dose STZ(28mg/kg).After successfully modeled,Irbesartan(50mg/kg/d)was given to the DN+I group,and the same amount of normal saline was given to the NC group and the DN group.The body mass,random blood glucose and 24-hour urine protein of the rats were measured regularly.The day before the rats were killed,blood samples were taken from the eye sockets to determine biochemical indexes such as serum creatinine and urea nitrogen.At the end of the 22 nd week,the rats were killed and the kidneys were removed.The renal tissue was stained with HE and Masson,and the morphological changes of renal tissue were observed under light microscope.The expression of mi R-93 in renal tissue was detected by q RT-PCR method,Western blot and immunohistochemistry were used to detect expressions of VEGF,FN,Col-IV in kidney.Results1.Comparison of routine indexes and urinary protein in each group:compared with NC group,levels of FBG,BUN,SUA and 24 h UA1b in DN group were significantly higher than those in DN group(P<0.05).Compared with DN group,levels of SUA and 24 h UA1b in DN+I group decreased significantly(P<0.05);But there was no significant change in levels of FBG and BUN(P > 0.05).However there was no significant difference in Scr level among the three groups(P > 0.05).2.Pathological changes of kidney in rats of each group:The result of HE staining showed that the structure of glomerulus,renal tubule and renal interstitium in NC group was clear,and there were no obvious pathological changes.In DN group,there were some pathological changes in kidney,such as lobular changes of glomerular capillary loop,narrowing of renal capsule,proliferation of Mesangial cells,increase of Mesangial matrix,broadening of Mesangial area,vacuolar degeneration of renal tubular epithelial cells and infiltration of inflammatory cells in renal interstitium.The above pathological changes in DN+I group were slighter than those in DN group.Masson staining showed that a small amount of collagen fibers could be seen in glomerular Mesangial area and renal interstitium in NC group,and obvious accumulation of collagen fibers in glomerular Mesangial area and interstitium could be seen in DN group.Collagen fiber deposition in DN+I group was less than that in DN group.3.The results of q RT-PCR: Compared with NC group,the expression of mi R-93 in DN group decreased significantly,and compared with DN group,the expression of mi R-93 in DN+I group increased significantly(P < 0.05).4.Western blot results: The expression of VEGF protein in DN group was more than that in NC group,and the expression of VEGF protein in DN+I group was significantly lower than that in DN group(P < 0.05).5.The immunohistochemical results showed that VEGF,FN and Col-IV were all expressed in the cytoplasm;VEGF was mainly expressed in glomerular Mesangial area,tubular epithelial cells and renal interstitium;FN was mainly expressed in renal tubular epithelial cells and renal interstitium,and Col-IV was mainly expressed in glomerular Mesangial area and renal interstitium.compared with NC group,the positive staining granules and staining area in DN group were significantly increased,while those in DN+I group were less than those in DN group.Conclusion In this experiment,through the study of DN rat model,it was found that the 24 h UA1b and renal pathological changes of DN rats were significantly alleviated after Irbesartan treatment,which further confirmed the protective and therapeutic effect of Irbesartan on DN kidney.The expression of mi R-93 in the kidney of DN rats was lower than that of normal rats,suggesting that the disordered expression of mi R-93 may be involved in the occurrence and development of DN.After treatment with Irbesartan,the expression of mi R-93 was significantly up-regulated,while the expression of VEGF,FN and Col-IV was significantly decreased,suggesting that Irbesartan may affect the expression of mi R-93 and further inhibit the expression of its target protein VEGF and its downstream effector molecules to play a role in renal protection.It not only provides a new idea for the diagnosis and treatment of DN,but also provides a new theoretical basis for ARB drugs and therapeutic target in the treatment of DN. |
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