The relationship between renal tubular epithelial cell, endothelin and renal interstitial fibrosis

Objective: To study the relationship between injured renal tubular epithelial cell, endothelin(ET), and renal tubulointerstitial fibrosis(TIF). Methods: Renal tubular epithelial cell and renal fibroblast were cultured in vitro , and reverse transcription polymerase chain reaction(RT PCR), immunohistochemical stain(IMC), radioimmuno assay (RIA) and double IMC were used, and the ratio of 3H TdR incorporation was measured to observe the relationship between ET 1 and proliferation of renal fibroblast. Results: There existed the expression of ET 1 mRNA and its receptors (ET A R mRNA and ET B R mRNA), and also the synthesis of ET 1 peptide in renal tubular epithelial cell. In the course of damage and regeneration, renal tubular epithelial cell produced more ET 1. The ratio of 3H TdR incorporation of renal fibroblast was higher than that of control group when ET 1 to was added this cultured cell. There existed the expression of ET B R mRNA in renal fibroblast. Conclusion: Injured and regenerated renal tubular epithelial cell produced and secreted more ET 1 than in normal kidney. ET 1 contributed to interstitial fibrosis by promoting the proliferation of renal fibroblast through ET R.