Quercetin Promotes the M1-to-M2 Macrophage Phenotypic Switch During Liver Fibrosis Treatment by Modulating the JAK2/STAT3 Signaling Pathway.

Objective: To investigate the underlying mechanism by which quercetin (Que) regulates macrophage polarization and its subsequent therapeutic effect on liver fibrosis, an important pathological precondition for hepatocellular carcinoma (HCC).

Methods: In vitro experiments were performed on the RAW264.7 mouse macrophage line. After the induction of M1-type macrophages with LPS, the effects of Que on cell morphology, M1/M2 surface marker expression, cytokine expression, and JAK2/STAT3 expression were analyzed. In vivo, male SD rats were used as a model of CCL4-induced hepatic fibrosis, and the effects of Que on serum aminotransferase levels, the histopathological structure of liver tissues, and macrophage-associated protein expression in liver tissues were analyzed.

Results: In vitro experiments revealed that Que can suppress the activation of the JAK2/STAT3 signaling pathway, leading to decreases in the expression of M1 macrophage surface markers and cytokines. Additionally, Que was found to increase the expression of M2 macrophage surface markers and cytokines. In vivo, assays demonstrated that Que significantly ameliorated the development of inflammation and fibrosis in a rat liver fibrosis model.

Conclusion: Que can inhibit hepatic fibrosis by promoting M1 to M2 macrophage polarization, which could be associated with its ability to suppress the JAK2/STAT3 signaling pathway in macrophages.