Quercetin alleviates CCl4-induced liver fibrosis via regulating gut microbiota and the AGE-RAGE/PI3K/Akt signaling axis

Abstract

The absence of clinically effective anti-fibrotic agents for chronic liver disease represents a critical therapeutic gap. Although the flavonoid quercetin exhibits potent experimental anti-fibrotic activity, its full integrative mechanisms—particularly those involving gut-liver axis crosstalk and specific signaling pathways—remain incompletely elucidated. To address this, we employed an integrated methodological approach encompassing network pharmacology, molecular docking, a CCl₄-induced murine model of liver fibrosis, 16S rRNA sequencing, and molecular validation to delineate quercetin's anti-fibrotic actions. Network analysis identified tumor necrosis factor (TNF), protein kinase B (Akt1), interleukin-6 (IL-6), and the AGE-RAGE/PI3K/Akt signaling axis as core targets and pathways, findings further corroborated by strong molecular binding affinities. In vivo, quercetin administration reversed CCl₄-induced body weight loss, ameliorated hepatic injury, reduced fibrogenesis markers, and attenuated pathological collagen deposition. Critically, quercetin restructured gut microbiota composition, enhancing α-diversity indices and favorably modulating the Bacteroidetes and Firmicutes ratio. Western blot analysis revealed quercetin's anti-fibrotic mechanism involves a dual inhibitory effect: primarily downregulating hepatic RAGE expression and concurrently suppressing PI3K-Akt pathway phosphorylation. These findings establish that quercetin ameliorates liver fibrosis through synergistic gut microbiota reprogramming and targeted disruption of the pathogenic AGE-RAGE/PI3K/Akt signaling axis, providing a mechanistic foundation for therapeutic development.