Effects of Erythropoietin on Renal Interstitial Fibrosis in Rats

Objective To investigate the effect and mechanism of erythropoietin on renal tubulointerstitial fibrosis in rats with unilateral ureteral obstruction(UUO).Methods Thirtysix sprague-dawley rats were randomly divided into the control group(A),the UUO model group(B)and the treatment group(C).The group B and C were undertaken UUO operation.The treatment group rats were treated with intraperitoneal injection of Erythropoietin(1000 U/kg)at 1 day preoperation and at day 2,5 and 8 post-operation.On the 10th day of UUO,rats were killed and their operated kidneys were processed to paraffin sections with HE and PAS staining.The pathological change of renal tubular interstitial tissue and relative cortical/interstitial volume(C/I)were observed by light microscope.The expression of transforming growth factor-β1(TGF-β1),α-smooth muscle actin(α-SMA)and collagen I in the renal mesenchyma were examined by immnohistochemistry.Results Marked renal interstitial fibrosis changes were found in group B and C,but the changes were milder in group C.C/I were higher in group B and C as compared with those in group A(P0.01),but they were much lower in group C than.in group B(P0.01).The expression of TGF-β1,α-SMA and collagen I were higher in group B and C than those in group A(P0.01),but they were lower in group C than in group B(P0.01).Conclusion Erythropoietin could ameliorate renal tubulointerstitial fibrosis in rats,which might be partially realized by down-regulation the expression of TGF-β1 to prevent the epithelial-mesenchymal transition.