Blockade Of Midkine Contributes To The Attenuation Of Renal Fibrosis Through Activation Of Th2 Cells

Objective:To investigate the effects of midkine(MK)in RIF and its effect on CD4~+T cells and CD4~+T cell subsets during the inflammatory response of RIF.Methods:1.The UUORIF model was established.The expression of MK was inhibited by injection of antisense oligodeoxyribonucleotides(ODN)through tail vein.The pathological changes of damaged kidneys were observed by Masson staining.2.The relationship between MK,CD4+T cells,T cell subsets,cytokines and chemokines in spleen and kidney of model mice was observed by immunohistochemical staining,flow cytometry and Q-PCR.3.The interaction between MK and CD4~+Foxp3~+Treg cells was determined by flow cytometry and Q-PCR.Results:1.The results of Masson staining showed that there was significant collagen deposition in the damaged kidney after UUO,After the inhibition of MK expression,the degree of RIF increased significantly at 14d,and the fibrosis of kidney decreased significantly at 7 d.2.The results of immunohistochemical staining showed that CD4~+T was increased in UUO mice.Inhibition of MK expression by antisense ODN could significantly inhibit tissue infiltration of CD4~+T cells.3.Flow cytometry analysis showed that CD4~+CD69~+activated T cells increased during RIF.The number of infiltrating IL-4~+CD4~+T cells in the renal tissue was significantly higher than that in control mice,while IFN-γ~+and IL-17~+CD4~+cells were not significantly altered,The inhibition of MK expression by antisense ODN significantly reduced the number of CD4~+T cell subsets in renal tissue.The CD4~+Foxp3+Treg cells in the spleen and kidney of UUO mice showed a decreasing trend,MK antisense ODN inhibits the expression of MK and increases the number of CD4~+Foxp3~+Treg cells in the spleen and kidney.Conclusion:MK can promote the infiltration of Th2 cells by reducing the immunosuppressive effect of CD4~+Foxp3~+Treg cells in the course of renal fibrosis.Targeted blocking of MK expression promotes CD4~+Foxp3~+Treg cell activation and function,Furthermore,the infiltration of activated CD4~+T cells and Th2 cells were decreased and the degree of interstitial fibrosis was improved.