Abstract: Objective To investigate the preventive effects of bufalin on transforming growth factor-beta 1（TGF-β1） induced epithelial-mesenchymal transition of human kidney cells． Methods Human kidney proximal tubular cell line （HK-2）was used as the proximal tubular cell model． Cells were divided into five groups as follows：control group， TGF-β1 （5 μg /L） group， TGF-β1 （5 μg/L） plus bufalin （1×10-9、1×10-8 and 1×10-7mol/L） groups． Epithelial to mesenchymal transition（EMT） was induced with 5 μg/L of human TGF-β1． The effects of bufalin on cell morphology were observed by phase contrast microscopy， the expression of α-smooth muscle actin （α-SMA） and E-cadherin were measured by immunofluorescent staining， real-time reverse transcription-polymerase chain reaction and western blot. Results Our results revealed that bualin not only prevented α-SMA expression(P<0.05) but also prohibited the decrease of the epithelial marker E-cadherin(P<0.05) in HK-2 cells in a dose-dependent manner. Simultaneous incubation of bufalin with TGF-β1 could protect the change to the myofibroblast phenotype and restore the epithelial morphology of the HK-2 cells. Conclusion These observations strongly suggest that bufalin is a potent inhibitor of TGF-β1-induced EMT and may be a promising agent for treating tubulointerstitial fibrosis．

Key words: bufalin, transforming growth factor-β1, epithelial-mesenchymal transition