Protective Effect Of Hepatocyte Growth Factor On Rat Kidney After Unilateral Ureteral Obstruction

Objective:Renal interstitial fibrosis is a major determinant of loss of renal function leading to end-stage renal disease regardless ofthe nature of the initial insult.The progression of renal interstitial fibrosis is a complex process involving various intricate intracellular signaling pathways.The affection of renal tubulointerstitium and its degree decides the prognosis of renal disease.And approaching the nosogenesis,prevention and cure for renal tubulointerstitium fibrosis has important clinical meaning.TGF-β1 is an important cytokine that has been implicated in the pathogenesis of numerous fibrotic diseases. TGF-β1 induces renal interstitial fibrosis by promoting podocyte,endothelial,and tubular epithelial cell apoptosis,by activating mesangial cells and interstitial fibroblasts to produce massive amounts of matrix components,and by initiating mesenchymal transition of tubular epithelial cells.These actions of TGF-β1 lead to glomerulosclerosis and tubulointerstitial fibrosis,and,ultimately,to end-stage renal failure.Recent reports showing activin receptor-like kinase ALK ser/thr kinase memberance receptors,in particular the ALK5,specifically induces many profibrotic actions of TGF-β1,suggesting that ALK5 may play a decisive role in the pathogenesis of chronic renal interstitial fibrosis.The ALK5 receptor has been shown to activate the Smad and the p38 mitogenactivated protein kinase (MAPK)signaling pathways,which have both been implicated in the up-regulation of ECM proteins.Hepatocyte growth factor(HGF)is a pleiotropic factor that plays an imperative role in tubular repair and regeneration after acute renal injury.HGF inhibits TGF-β1 expression;suppresses myofibroblastic activation and matrix overproduction;accelerates matrix degradation;blocksTubularEpithelial-To-MesenchymalTransitio n;inhibits apoptosis;modulates cell proliferation to protecting the kidneys.Hepatocyte growth-promoting factor for injection is extracted from the liver of animals small molecule peptide substances,mainly used in severe hepatitis and cirrhosis of the early clinical treatment.At present,we haven't retrieval the influence of Hepatocyte Growth-promoting Factors for Injection for the expression of HGF,TGF-β1,ALK5 in UUO(unilateral ureteral occlusion)rat analog.The study is to investigate the expression of HGF,TGF-β1,ALK5 and the influence of Hepatocyte Growth-promoting Factors for Injection for the expression in renal interstitial fibrosis from observating changes of pathology in kidneys and detecting HGF,TGF-β1,ALK5 by immunohistochemistry through UUO rat analog treated by Hepatocyte Growth-promoting Factors for Injection.The final purpose is to explore directory theory for curing renal interstitial fibrosis in clinic.Methods:54 male Wistar rats were randomly divided into 3 groups:sham-operated group(A),UUO group(B),UUO with HGF treated group(C),(n=18).Each group was also randomly divided into 3,7,14 groups in term of the days after surgery(n=6).Under Chloral Hydrate anesthesia(0.1ml/Kg body weight,i.p),the left ureter was ligated by 4.0 silk at two points and cut between the ligatures in order to prevent retrograde urinary tract infection.Sham-operated group had their ureters manipulated but not ligated.Hepatocyte Growth-promoting Factors for Injection[0.5mg/(Kg·d)]began to administrate one day before surgery.UUO and sham groups were received equal volume NS by daily injection.All rats were allowed free access to food and water.Rats were killed in the 3,7,14 days after surgery.In obstructed kidney,histological changes were observed by HE stain and Masson stain,HGF,TGF-β1,ALK5 were examined by immunohistochemical method.The results were analyzed semi-quantitatively with the pathological image analysis system.All the data were analyzed by SPSS13.0statistics software,P value＜0.05 was considered to have statistical significance.Results:There were different degrees of interstitial fibrosis,interstitial leukocyte infiltration,tubular dilation and the relative area of renal tubulointerstitium expantion in the obstructed kidneys of groups B₃,B₇,B₁₄days after UUO in light microscrope using the staining mathods of HE and Masson.The relative area of renal tubulointerstitium was significantly increased in the obstructed kidneys compared with that of group A(P＜0.01).However,the relative area of renal tubulointerstitium of group C significantly decreased compared with that of group B(P＜0.01).The results of immunohistochemical staining: TGF-β₁ was mainly localized in renal tubule interstitium in group A.While the level of TGF-β₁ in group B was significantly increased than that of group A.In group C,the level of TGF-β₁ was lower than that of group B at the same timepoint(P＜0.05). ALK5 mainly expressed in renal tubule and had a small quantity of expression in renal interstitial in group B.There was almost no expression in group A.The level of ALK5 in group C was decreased than that in group B at the same timepoint(P＜0.05).HGF was almost no expression of the period in group A.In Group B,HGF main expression in renal tubular epithelial cells,the highest expression of the first three days, seven days a slight decline,the first 14 days of the weakest,but were higher than the same period in Group A(P＜0.05). Compared with the same period in group B,group C after 3 days,7 days,14 days the expression of TGF-β1 were significantly higher than the same period of Group B(P＜0.05).Conclusion:Expression of TGF-β1 and ALK5 is increasingly strong in the renal intertitial of unilateral ureteral obstruction rats and their expression develop more than before as time goes on,RIF appears.Threpy group markedly limit expression of TGF-β1 and ALK5 and inhibit RIE Expression of HGF is decreasingly strong in the renal intertitial of unilateral ureteral obstruction rats and their expression develop less than before as time goes on,RIF appears.Threpy group markedly limits expression of HGF and inhibits RIE Expression of HGF is decreasingly strong in the renal intertitial of unilateral ureteral obstruction rats and their expression develop less than before as time goes on,RIF appears.Threpy groups markedly enhance expression HGF and inhibit RIE Hepatocyte Growth-promoting Factors for Injection can improve changes of histomorphology in kidney of UUO rat,lighten renal tubule extension, mononuclear-lymphocyte infiltration and deposition of collagen in renal interstitium.