The role and mechanism of tumor necrosis factor-α in the formation of chronic transplant renal interstitial fibrosis / 中华器官移植杂志

ABSTRACT

Objective To explore the role and mechanism of tumor necrosis factor-α (TNF-α) in the formation of chronic transplant renal interstitial fibrosis and to study Smurf2 expression change and role played in this process.Methods We collected 26 cases of normal renal tissues and 26 cases of renal allograft specimens from chronic allograft dysfunction patients to observe the degree of renal interstitial fibrosis by Hematoxylin and eosin (HE) staining and Masson staining.Immunohistochemical staining was applied to detect the expression and distribution of E-cadherin,α-smooth muscle actin (α-SMA) and TNF-α,Smad ubiquitination regulatory factor 2 (Smurf2).Furthermore,The HK2 cells were divided into five groups depending on different concentrations of TNF-α (0,10,20,50,and 100 ng/mL).After 48 h,we collected the cells to analyze the expression changes of Smurf2,E-cad,α-SMA by Western blotting.Results As compared with normal group,the degree of renal interstitial fibrosis in CAD group was aggravated according to the results of HE and Masson staining (P＜0.01).Immunohistochemical staining results showed that the positive expression of E-cadherin was reduced,and that of α-SMA,TNF-α and Smurf2 increased greatly in CAD group as compared with normal group (P＜0.01).The results of Western blotting also revealed that after treatment with different concentrations of TNF-α for 48 h,the expression of E-cadherin was downregulated,and that of α-SMA and smurf2 was up-regulated in HK2 cells (P＜0.05).Conclusion TNF-α may promote the formation of allograft renal interstitial fibrosis via transdifferentiation of human tubular epithelial cells to mesenchymal cells by up-regulating the expression of Smurf2.