Preventive effects of salvianolic acid B on transforming growth factor-beta1-induced epithelial-to-mesenchymal transition of human kidney cells.

Epithelial-mesenchymal transition (EMT) is an important mechanism in kidney fibrosis. While Salvianolic acid-B (Sal B) has been well appreciated to show a protective effect of tissue fibrosis, the objective of this study was to investigate the influence of Sal B on the transdifferentiation of renal tubular epithelial cells. Human kidney proximal tubular cell line (HK-2) was used as the proximal tubular cell model and EMT was induced with 5 ng/ml of human transforming growth factor (TGF)-beta1. The effects of the Sal B on cell morphology were observed by phase contrast microscopy, and the possible mechanisms were studied by immunocytochemistry and real-time reverse transcription-polymerase chain reaction. Our results revealed that Sal B could inhibit TGF-beta1-induced myofibroblast phenotype and restored the epithelial morphology in a dose-dependent manner. It was partially through modulating alpha-smooth muscle actin (SMA) increase and E-cadherin reduction. These observations strongly suggest that Sal B is a potent inhibitor of TGF-beta1-induced EMT and might be a promising agent for treating tubulointerstitial fibrosis.