Proposed mechanistic pathways for the protective effect of PLP against TAA-induced liver fibrosis in rats. Liver proteins with significant expression changes detected by the 2-DE proteomics analysis are used to construct the possible pathways. These include the antioxidant system, iron metabolism regulation pathways (haptoglobin, hemopexin), and amino acid and nucleic acid metabolic pathways (homocysteine, BHMT, GSTA4). Upward arrowheads indicate upregulation or increasing, and downward arrowheads indicate downregulation or decreasing. BCAAs: branched-chain amino acids; BCKAs: branched-chain α-keto acids; BC acyl-CoA: branched-chain acyl-CoA.