Anti-liver fibrosis effects of the total flavonoids of litchi semen on CCl 4 -induced liver fibrosis in rats associated with the upregulation of retinol metabolism

The litchi semen are traditional medications for treating liver fibrosis (LF) in China. The mechanism remains unclear.This study investigates the anti-liver fibrotic mechanism of the total flavonoids of litchi semen (TFL).Sprague-Dawley rats with carbon tetrachloride-induced LF were treated with TFL (50 and 100 mg/kg) for 4 weeks. The anti-liver fibrotic effects of TFL were evaluated and the underlying mechanisms were investigated via histopathological analysis, proteomic analysis and molecular biology technology.Significant anti-LF effects were observed in the high-TFL-dose group (TFL-H, p < 0.05). Five hundred and eighty-five and 95 differentially expressed proteins (DEPs) were identified in the LF rat model (M group) and TFL-H group, respectively. The DEPs were significantly enriched in the retinol metabolism pathway (p < 0.0001). The content of 9-cis-retinoic acid (0.93 ± 0.13 vs. 0.66 ± 0.10, p < 0.05, vs. the M group) increased significantly in the TFL-H group. The upregulation of RXRα (0.50 ± 0.05 vs. 0.27 ± 0.13 protein, p < 0.05), ALDH2 (1.24 ± 0.09 vs. 1.04 ± 0.08 protein, p < 0.05), MMP3 (0.89 ± 0.02 vs. 0.61 ± 0.12 protein, p < 0.05), Aldh1a7 (0.20 ± 0.03 vs. 0.03 ± 0.00 mRNA, p < 0.05) and Aox3 (0.72 ± 0.14 vs. 0.05 ± 0.01 mRNA, p < 0.05) after TFL treatment was verified.TFL exhibited good anti-liver fibrotic effects, which may be related to the upregulation of the retinol metabolism pathway. TFL may be promising anti-LF agents with potential clinical application prospects.