The Pathogenic Mechanism Of Interleukin-22 To Diabetic Kidney Injury And The Protection Effect On Kidney By Targeted Intervention

Part One:Objective:To investigate the effects of interlukin-22(IL-22)on diabetic renal fibrosis and its possible mechanism.Methods:C57 BL/6 mice were randomized to normal control group(NC group),diabetic nephropathy control group(DN group),recombinant interlukin-22(rIL-22)group,and interlukin-22 antibody(Anti-IL-22)group.After the intervention,24 h urine microalbumin creatinine ratio were measured.Renal pathological changes were observed under the light microscope.The mRNA expression of TGF-?1 and Snaill was determrmined by realtime PCR.The protein expressions of a-smooth muscle actin(a-SMA),E-cadherin,and fibronetin(FN)were examined by western blot.The protein expressions of collagen ? were examined by immunohistochemical analysis.Results:1)After 4 weeks of intervention,the 24 h urine microalbumin creatinine ratio decreased significantly in the Anti-IL-22 group(P<0.05).2)Renal tubular epithelial cells vacuolar degeneration,protein cast formation and glomerular mesangial expansion were observed under the light microscope.And the lesions were more severe in the rIL-22 group,whereas improved in the Anti-IL-22 group.3)Moreover,TGF-?1 gene expression increased significantly in the rIL-22 group(P<0.01).4)Snaill gene expression increased significantly in the diabetes model mice(P<0.05),while decreased significantly after a 4-week intervention by Anti-IL-22(P<0.05).5)a-SMA and E-cadherin,epithelial-mesenchymal transition(EMT)markers,increased or decreased significantly in the rIL-22 group respectively(P<0.05).6)FN and collagen ?,extracellular matrix(ECM)proteins,increased significantly in the rIL-22 group as well(P<0.05).Conclusion:IL-22 may induces renal tubular epithelial cells TGF-?1 high expression.As a consequence,this contributes to EMT going on and ECM accumulation,eventually accelerating the progression of diabetic renal fibrosis.In addition,IL-22 neutralizing antibody may improve microalbuminuria and delay the progression of DN via inhibition on Snaill expression in the renal tubular epithelial cells.IL-22 and DN are closely related.Part Two:Objective:To explore the expressions of interleukin-22(IL-22)and soluble tumor necrosis factor receptor ?(sTNFR ?)in type 2 diabetic patients,as well as the correlation with urinary albumin excretion rate.Methods:67 diabetic outpatients were divided into normal urinary albumin group,micro-urinary albumin group and macro-urinary albumin group.And 30 normal subjects were set as the control group.Serum IL-22 and sTNFR ? were detected by Elisa.Kidney function,plasma glucose,blood fat,uric acid and urinary albumin excretion rate were detected by automatic biochemical analyzer.Results:1)Serum IL-22 and sTNFR ? increased significantly more in the type 2 diabetic group than in the normal control group(P<0,05).2)Moreover,serum IL-22 and sTNFR ? were positively correlated(r=0.303,P=0.005).3)However,there were no significant difference among different urinary albumin excretion rate patient in IL-22 and sTNFR ?(P>0.05).4)FPG in the micro-urinary albumin group and cystatin C(CysC),Scr,BUN,FPG,HbAlc in the macro-urinary albumin group increased significantly more than in the normal urinary albumin group(P<0.05).CysC and BUN in the macro-urinary albumin group increased significantly more than in the micro-urinary albumin group(P<0.05).Conclusion:Serum IL-22 and sTNFR ? are upregulated and closely positively correlated in the type 2 diabetic patients,which may play important roles in the development of type 2 diabetes mellitus.It indicates that targeting the IL-22 and sTNFR ? to interfere the chronic low grade inflammation is of significant clinical value.