Asiatic acid ameliorates tubulointerstitial fibrosis in mice with ureteral obstruction

Asiatic acid (AA) is one of the triterpenoid compounds present in Centella asiatica and it has been shown to be capable of attenuating liver fibrosis. In the present study, we investigated the effects of AA on renal tubulointerstitial fibrosis in mice with unilateral ureteral obstruction (UUO). Mice were divided randomly into five groups (n=5 per group): the sham-surgery (Sh), UUO plus vehicle treatment (UUO+V), UUO plus 1 mg/kg body weight AA treatment (UUO+A1), UUO plus 4 mg/kg body weight AA treatment (UUO+A2) and UUO plus 16 mg/kg body weight AA treatment (UUO+A3) groups. The mice were treated with AA daily by oral gavage from the day subsequent to surgery for six days. On the seventh day, the mice were sacrificed for examination. Tubular injury was observed in the renal cortex of the mice administered the vehicle, while high doses of AA were observed to exert a significant suppressive effect on tubular injury. Interstitial fibrosis, increased expression of α-smooth muscle actin (SMA) and transforming growth factor (TGF)-β1 and phosphorylation of Smad2/3 were induced by ureteral ligation; however these effects were abrogated by intermediate and high doses of AA. These results suggest that AA may ameliorate tubulointerstitial fibrosis by reducing tubular injury, fibroblast activation and extracellular matrix (ECM) accumulation mediated by Smad-dependent TGF-β1 signaling.