Background: Cistanche tubulosa is a traditional Chinese herbal medicine that is widely used for regulating immunity. Phenyl ethanol glycosides (CPhGs) from this plant are the primarily efficacious materials. This aim of this study was to evaluate the preventive and therapeutic effects of CPhGs on BSA-induced hepatic fibrosis in rats and related molecular mechanisms involving hepatic stellate cells. Biejiarangan (BJRG), another traditional Chinese herbal medicine, was used as a positive control.
Methods: In in vivo experiments, 75 SD rats were randomly divided into 6 groups: normal (distilled water-treated), model (BSA-treated), positive drug (BSA-treated + BJRG 600 mg/kg/day), and BSA-treated + CPhGs (125, 250, and 500 mg/kg/day) groups. The liver and spleen indices, serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), hexadecenoic acid (HA), laminin (LN), type III procollagen (PCIII), type IV collagen (IV-C), hydroxyproline (Hyp), and transforming growth factor β 1 (TGF-β 1) were measured in rat livers. Histopathological grades for liver fibrosis were assessed for each group using H&E and Masson's trichrome staining. The expression of TGF-β 1, collagen I (Col-I) and collagen III (Col-III) were determined by an immunohistochemical staining method. These effects were further evaluated in vitro by determining expression levels of NF-κB p65 and Col-I by quantitative real-time PCR analyses. Col-I protein expression was also examined by western blotting.
Results: All dose groups (125, 250, and 500 mg/kg/day) of CPhGs significantly reduced the liver and spleen index, decreased ALT, AST, HA, LN, PCIII, IV-C serum levels, TGF-β 1 content (P < 0.01, P < 0.01, and P < 0.01), and Hyp content. CPhGs also markedly alleviated the swelling of liver cells and effectively prevented hepatocyte necrosis and inflammatory cell infiltration. Immunohistochemical results showed that CPhGs significantly reduced the expression of TGF-β 1 (P < 0.01, P < 0.01, and P < 0.01), Col- I, and Col-III. The in vitro effects of CPhGs (100, 75, 50, and 25 ug/ml) on HSC-T6 showed that CPhGs significantly reduced mRNA expression of NF-κB p65 and Col-I, and CPhGs also downregulated Col-I protein expression.
Conclusions: CPhGs have a significant anti-hepatic fibrosis effect, and may be used as hepatoprotective agents for treatment of hepatic fibrosis.