Inhibition of the tubular epithelial-to-mesenchymal transition in vivo and in vitro by the Uremic Clearance Granule ()

Abstract

Objective: To investigate the effect of the Uremic Clearance Granule (UCG, ), a Chinese patent medicine, on tubular epithelial-to-mesenchymal transition (EMT) in a unilateral ureteral obstruction (UUO) model in vivo and transforming growth factor (TGF)-β1 induced EMT of HK-2 cells in vitro.

Methods: In vivo study, 50 Sprague Dawley rats were divided into three groups: a sham operation group (n=10), a UUO group (n=20), and a UUO with UCG treatment group (n=20). The UCG was given at a dose of 4.5 g/kg body weight per day by gavage after surgery. In vitro study, HK-2 cells were cultured in 10% fetal bovine serum (FBS), 10% healthy rat serum, 10% FBS and TGF-β1 (10 ng/mL), 10% healthy rat serum and TGF-β1, or 10% rat serum containing the uremic clearance granule and TGF-β1. The expression of the epithelial marker E-cadherin and the mesenchymal markers vimentin and α-smooth muscle actin (α-SMA) in kidney tissues and HK-2 cells were investigated by Western blot analysis and immunofluorescence staining.

Results: The rats of the UUO group showed obvious tubulointerstitial fibrosis, compared with the sham operation group rats. Tubulointerstitial fibrosis score was reduced by 17.5%±1.1% at day 7 and by 20.0%±1.2% at day 14 in the UCG-treated group, compared with the UUO group. The UCG could maintained expression of E-cadherin and suppressed expression of vimentin and α-SMA in kidney tissues of UUO rats at days 7 and 14, as determined by Western blot analysis and immunofluorescence staining. Rat serum containing the UCG partially inhibited TGF-β1-induced fibroblast phenotype of HK-2 cells and maintained the epithelial morphology of HK-2 cells in vitro. This occurred partially through a reduction of vimentin expression and an increase of E-cadherin expression.

Conclusion: These results suggest that the UCG prevents tubular EMT and may be a promising agent for treating tubulointerstitial fibrosis.