Protective effects of baicalin on diethyl nitrosamine‐induced liver cirrhosis by suppressing oxidative stress and inflammation

Baicalin (BA) is a natural product extract with anti-inflammatory, antioxidant, and hepatoprotective properties. Given that the exact underlying mechanisms responsible for the impact of BA on liver cirrhosis remain ambiguous, a detailed investigation is sorely needed. Accordingly, a rat liver cirrhosis model was established via the intraperitoneal injection of diethyl nitrosamine (DEN, 100 mg/kg). Following the modeling, these rats were given BA (100 mg/kg) or N-acetylcysteine (NAC, 150 mg/kg) alone or in combination. The pathological morphology of rat liver tissues in each group was observed by hematoxylin and eosin staining and Masson's trichrome staining. The expression of fibrosis-related proteins was evaluated by Western blot, and the levels of liver function-related biochemical indexes, oxidative stress-related indexes, and inflammatory factors in the serum by enzyme-linked immunosorbent assays (ELISA). The level of mitochondrial reactive oxygen species was measured by flow cytometry. The results depicted that in the rat model of DEN-induced liver cirrhosis, BA reduced the expression of fibrosis-related proteins (collagen type I alpha 1, α-smooth muscle actin, and transforming growth factor-β1), thereby alleviating the structural fibrosis of liver tissue. Furthermore, BA could diminish the level of mitochondrial reactive oxygen species, and the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA), interleukin (IL)-1β, IL-6, tumor necrosis factor-α (TNF-α), and monocyte chemotactic protein-1 (MCP-1), while promoting albumin, superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) levels. Notably, all these effects of BA above were strengthened following the combined treatment of BA and NAC. On the whole, BA suppresses liver fibrosis by inhibiting oxidative stress and inflammation, thereby exerting a hepatoprotective effect.