The effects of the selective mineralocorticoid receptor antagonist eplerenone on hepatic fibrosis induced by bile duct ligation in rat

The aim of this study was to examine the effects of eplerenone on hepatic fibrosis induced by bile duct ligation (BDL) in rat. Low- (1.0 mg/kg body weight, BW) and high- (4.0 mg/kg BW) dose eplerenone was administered orally for 21 days immediately following BDL. Fibrosis was assessed by measuring the fibrotic area after Sirius red staining. Immunostaining for α-smooth muscle actin (SMA), 4-hydroxy-2-nonenal (4-HNE) and 8-hydroxy-2-deoxyguanosine (8-OHdG) was also carried out. Gene expression levels of procollagen-I, transforming growth factor-β1 (TGF-β1), connective tissue growth factor (CTGF), tissue inhibitor of metalloproteinases-1 (TIMP-1) and matrix metalloproteinase-13 (MMP-13) in the liver were examined by real-time reverse transcriptase polymerase chain reaction. Plasma angiotensin II (ATII) concentration was measured via radioimmunoassay. The area of hepatic fibrosis and α-SMA positivity in the high-dose group was significantly decreased compared with that in the BDL group, but not in the low-dose group. 8-OHdG-positive cells in the low- and high-dose groups were significantly decreased compared with those in the BDL group. Immunostaining of 4-HNE in the high-dose group was significantly lower compared with that in the BDL group. Furthermore, TIMP-1 mRNA levels in the low- and high-dose groups were lower than that in the BDL group. The expression of TGF-β1, CTGF, procollagen-1 and MMP-13 showed no differences. Plasma ATII concentration in the high-dose group was significantly decreased. Eplerenone attenuated the development of BDL-induced hepatic fibrosis by reducing oxidative stress, suppressing activated hepatic stellate cells and decreasing plasma ATII levels. Eplerenone may prove useful as an alternative treatment for antifibrosis therapy.