Effects of salvianolic acids on oxidative stress and hepatic fibrosis in rats

Reactive oxygen species (ROS) is associated with activation of hepatic stellate cells (HSCs) and liver fibrosis in vivo. The present study is to investigate the in vitro and in vivo anti-fibrotic effects of salvianolic acids A (Sal A, C₂₆H₂₂O₁₀) and B (Sal B, C₃₆H₃₀O₁₆) from Salvia miltiorrhiza. A cell line of rat HSCs (HSC-T6) was stimulated with platelet-derived growh factor (PDGF, 10ng/ml). Intracellular hydrogen peroxide (H₂O₂), α-smooth muscle actin (α-SMA), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits and phosphorylations of mitogen-activated protein kinases (MAPKs) were measured. Liver fibrosis was induced by intraperitoneal injections of thioacetamide (TAA, 200mg/kg) twice per week for 6 weeks. Sal A (10mg/kg), or Sal B (50mg/kg) was given by gavage twice per day for 1 month starting 2 weeks after TAA injection. PDGF increased the accumulation of hydrogen peroxide in HSCs, which was attenuated by Sal A (10µM) and Sal B (200µM). Sal A and B attenuated the PDGF-stimulated expressions of NADPH oxidase subunits gp91^phox and p47^phox in membrane fractions. Sal B reversed PDGF-stimulated phosphorylations of p38 and JNK. In vivo studies showed that the hepatic collagen contents, fibrosis scores and expressions of α-SMA and gp91^phox were increased in TAA-intoxicated rats, all of which were attenuated by Sal A and Sal B treatment. Our results showed that Sal A and B attenuated PDGF-induced ROS formation in HSCs, possibly through inhibiton of NADPH oxidase. Sal A and B treatments were also effective against hepatic fibrosis in TAA-intoxicated rats.