| Objective:In recent years,many studies show that inflammatory factors play an important role in the pathogenesis of DN.More recent studies find that interleukin 22(IL-22)and IL-22 receptor(IL-22R)are associated with inflammation and autoimmune diseases.So far,no relevant research reports whether IL-22/IL-22 R play a role in the pathogenesis of DN.The effect of artificial fermentation cordyceps sinensis powder is very similar to that of natural cordyceps sinensis.Related studies find that the fermentation cordyceps sinensis powder can relieve kidney damages in patients with DN.However,the mechanism of effect is not clear.In this study,we use diabetic rat model to observe the role of IL-22/IL-22 R in the development of DN,and at the same time,to observe whether cordyceps sinensis powder can improve the renal pathological changes in diabetic rats through affecting the expression of IL-22/IL-22 R in the kidney.Methods:Forty-five sprague-dawley rats were selected,among which 15 were randomly selected as the control group(NC group).The diabetic model was established by intravenous injection of streptozotocin(STZ,45mg/Kg)in the remaining 30 rats.Twenty-eight diabetic rats that successfully established diabetic rats models were randomly divided as the artificial fermentation cordyceps sinensis powder treatment group(CS group,1 g·kg-1·d-1)and the untreated diabetes group(DM group),with 14 rats in each group.In the CS group,artificial fermentation cordyceps sinensis powder solution was given once a day by gavage.meanwhile,0.9%NaCl solution was given daily to the DM group and the NC group by gavage.24-hour urine from rats was collected at the end of 18 weeks,and the 24-hour urinary albumin(24h UMA)was measured.Blood creatinine(Scr),blood urea nitrogen(BUN)were tested,and renal/body mass index were calculated.After HE staining,pathological changes of renal tissues in rats were observed under optical microscopy and submicroscopic structures were observed under electron microscopy.Immunohistochemistry,Western Blot and RT-PCR were used to determine the degree of IL-22 and IL-22 R in renal tissues of rats in each group.Results:1.At the end of 18 week,there was no significant difference in weight between the DM and CS groups.2.Blood glucose,kidney/body mass index,blood BUN,Scr and 24 h UMA were significantly decreased in the DM group.Kidney/body mass index,BUN,Scr and 24 h UMA were significantly lower in the CS group than in the DM group.There was no significant difference in blood glucose between the CS group and the DM group.3.HE staining showed that vacuolar degeneration of proximal renal tubular epithelial cells in DM group and CS group rats.Significant proliferation of mesangial cells,thickening of capillary basement membrane of renal glomerulus,and podocyte fusion pattern were observed under electron microscopy in DM group rats,The degree of kidney damage in rats of CS group were significantly relieved than that of DM group.4.Immunohistochemical results indicated that IL-22 and IL-22 R expression in rats of DM group and CS group were significantly higher than that of NC group.The expression of IL-22 and IL-22 R in the kidney of rats in the CS group was lower than that in the DM group.5.Western Blot and RT-PCR results showed that the expressions of IL-22 and IL-22 R in the kidney of rats in the DM group and the CS group were significantly higher than that of the NC group.The expression of IL-22 and IL-22 R in kidney of CS group was lower than that of DM group.Conclusion:1.Increased expression of IL-22 and IL-22 R in renal tissue may play an important role in diabetic nephropathy.2.Fermentation cordyceps sinensis powder can relieve kidney damage in diabetic rats,which may be related to the reduction of renal IL-22 and IL-22 R expression. |
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