Rosmarinic acid attenuates hepatic fibrogenesis via suppression of hepatic stellate cell activation/proliferation and induction of apoptosis

Objective:To investigate the antifibrotic role of rosmarinic acid(RA),a natural polyphenolic compound,on HSCs activation/proliferation and apoptosis in vitro and in vivo. Methods:The impact of RA on stellate cell line(HSC-T6) proliferation,activation and apoptosis was assessed along with its safety on primary hepatocytes. In vivo,rats were divided into:(i) normal;(ii) thioacetamide(TAA)-intoxicated rats for 12 weeks;(iii) TAA+silymarin or(iv) TAA+RA. At the end of experiment,liver functions,oxidative stress,inflammatory and profibrogenic markers,tissue inhibitor metalloproteinases type-1(TIMP-1) and hydroxyproline(HP) levels were evaluated. Additionally,liver histopathology and immunohistochemical examinations of alpha-smooth muscle actin(α-SMA),caspase-3 and proliferation cellular nuclear antigen(PCNA) were determined. Results:RA exhibited anti-proliferative effects on cultured HSCs in a time and concentration dependent manner showing an IC50 of 276 μg/mL and 171 μg/mL for 24 h and 48 h,respectively,with morphological reversion of activated stellate cell morphology to quiescent form. It significantly improved ALT,AST,oxidative stress markers and reduced TIMP-1,HP levels,inflammatory markers and fibrosis score(S1 vs S4). Furthermore,reduction in α-SMA plus elevation in caspase-3 expressions of HSCs in vitro and in vivo associated with an inhibition in proliferation of damaged hepatocytes were recorded. Conclusions:RA impeded the progression of liver fibrosis through inhibition of HSCs activation/proliferation and induction of apoptosis with preservation of hepatic architecture.