Taohong Siwu Decoction modulates glutathione metabolism to suppress hepatocyte ferroptosis and demonstrates anti-fibrotic effects in the liver.

ETHNOPHARMACOLOGICAL RELEVANCE: The ameliorative effect of traditional Chinese medicine (TCM) on hepatic fibrosis has been widely recognized and researched, but studies on the mechanism of action have been hampered by its complex composition, which requires more in-depth studies to elucidate why and how TCM works. The theory of TCM believes that the liver is closely related to blood circulation, and hepatic fibrosis is caused by blood stagnation. Taohong Siwu Decoction (THSW) is a classic formula for nourishing and invigorating blood and has been used clinically for centuries. Current evidence has demonstrated its ameliorative effect on hepatic fibrosis, but the exact mechanism of action remains unclear.

AIM OF THE STUDY: Exploring the possible mechanism of the anti-hepatic fibrosis effect of THSW by proteomics and validating with in vivo and in vitro studies.

MATERIALS AND METHODS: The carbon tetrachloride (CCl4)-induced fibrosis model was conducted in mice and treated with THSW in vivo with colchicine as the positive control. Then serum biomarker alanine aminotransferase (ALT), aspartate aminotransferase (AST), and histopathological analysis were evaluated to examine the effects of THSW. And hepatic fibrosis indicators alpha-smooth muscle actin (α-SMA) and Collagen Ⅰ (Col-Ⅰ) were detected by western blotting, immunohistochemistry and quantitative real-time polymerase chain reaction (qRT-PCR) analysis. Additionally, the 4D Label-free quantitative proteomic analysis of liver samples was applied. In vitro, erastin-induced BRL-3A cells, a rat hepatocyte line, were performed as a hepatocyte ferroptosis model and treated with or without drug-containing serum of THSW. Finally, molecular docking was used to verify the binding ability of the main components of THSW to potential targets.

RESULTS: THSW treatment significantly ameliorated serum ALT, AST, hydroxyproline (Hyp) content, α-SMA and Col-Ⅰ mRNA expression in fibrosis mice. Further results showed that THSW decreased the malondialdehyde (MDA) and 4-Hydroxynonenal (4-HNE) content and increased the glutathione (GSH) content of liver tissue. Notably, proteomic analyses have identified 294 differentially expressed proteins in the THSW-treated group compared to the model group, with 97 proteins up-regulated and 197 down-regulated. Functional analysis of these differential proteins highlights the significant roles of inflammation and oxidative stress. Further validation in vivo and in vitro, THSW significantly improved the protein expression of glutathione S-transferase M1 (GSTM1), down-regulate the expression of transferrin receptor (TFRC), and kelch-like ECH-associated protein 1(Keap1) proteins, and promote the metabolism of GSH. Especially it reduced serum iron levels, increased total iron binding capacity, and up-regulated recombinant solute carrier family 7, member 11 (SLC7A11), nuclear factor erythroid 2-related factor 2 (Nrf2), and glutathione peroxidase 4 (GPX4) protein expression, suggesting the inhibition of hepatocyte ferroptosis. In addition, the molecular docking results showed that its main components, amygdalin, hydroxysafflor yellow A, paeoniflorin, and albiflorin, possessed good binding ability with Keap1.

CONCLUSIONS: THSW represents a novel therapeutic effect on hepatic fibrosis in mice, accompanied by inhibiting hepatocyte ferroptosis. Mechanically, THSW may regulate the glutathione metabolic pathway and TFRC expression through its main ingredients, such as amygdalin, hydroxysafflor yellow A, paeoniflorin, and albiflorin, thereby inhibiting hepatocyte ferroptosis.