Transcriptomic analysis reveals pharmacological mechanisms mediating efficacy of Yangyinghuoxue Decoction in CCl4-induced hepatic fibrosis in rats
Authors: Bai Yanming , Liang Shuang , Zhou Yanhao , Zhou Bo 
Published: May 2024

Background and purpose

As a traditional Chinese medicine formula, Yangyinghuoxue Decoction (YYHXD) is used clinically for therapy of hepatic fibrosis. The pharmacological profile of YYHXD comprises multiple components acting on many targets and pathways, but the pharmacological mechanisms underlying its efficacy have not been thoroughly elucidated. This study aimed at probing the pharmacological mechanisms of YYHXD in the treatment of hepatic fibrosis.

Methods

YYHXD aqueous extract was prepared and quality control using HPLC-MS fingerprint analysis was performed. A CCl4-induced rat model of hepatic fibrosis was established, and animals were randomly assigned to six groups: control, low-dose YYHXD (L-YYHXD), medium-dose YYHXD (M-YYHXD), high-dose YYHXD (H-YYHXD), CCl4 model, and colchicine group. Rats in the treatment groups received daily oral administration of YYHXD (5, 10, or 20 g/kg) or colchicine (0.2 mg/kg) for 6 weeks, while the control and model groups received distilled water. Histological analysis, including hematoxylin and eosin (HE) and Masson’s trichrome staining, was performed to evaluate hepatic fibrosis. Serum biochemical markers, such as AST, ALT, HA, and LN, were measured. Inflammatory cytokines (IL-6 and TNF-α) and oxidative stress indicators (SOD, GSH-Px, and MDA) in hepatic tissue were also assessed. Additionally, transcriptomic analysis using RNA-sequencing was conducted to identify differentially expressed genes (DEGs) between the control, CCl4 model, and H-YYHXD groups. Bioinformatics analysis, including differential expression analysis, protein-protein interaction analysis, and functional enrichment analysis, were performed to probe the pharmacological mechanisms of YYHXD. The regulatory effects of YYHXD on fatty acid metabolism and biosynthesis were further confirmed by Oil Red O staining, enzyme activity assays, qPCR, and Western blotting. Western blotting and immunofluorescence staining also validated the involvement of the AMPK signaling pathway in the occurrence and progression of hepatic fibrosis.

Results

HE and Masson’s trichrome staining revealed reduced collagen deposition and improved liver architecture in YYHXD groups compared to the CCl4 model group. Serum biochemical markers, including AST, ALT, HA, and LN, were significantly improved in the YYHXD-treated groups compared to the CCl4 model group. The levels of inflammatory cytokines (IL-6 and TNF-α) and oxidative stress indicators (decreased SOD and GSH-Px, increased MDA) in hepatic tissue were significantly ameliorated by YYHXD treatment compared to the CCl4 model group. Moreover, 96 genes implicated in YYHXD therapy of hepatic fibrosis were screened from the transcriptomic data, which were principally enriched in biological pathways such as fatty acid metabolism and biosynthesis, and the AMPK signaling pathway. Oil Red O staining showed reduced hepatic lipid accumulation by YYHXD in a dose-dependent manner, along with decreased serum TG, TC, and LDL-C levels. Additionally, qPCR and Western blot analyses demonstrated upregulated mRNA and protein expression of key enzymes involved in fatty acid metabolism and biosynthesis, Fasn and Fads2, modulated by YYHXD. YYHXD also dose-dependently enhanced phosphorylation of AMPK as evidenced by Western blotting and immunofluorescence assays.

Conclusion

YYHXD ameliorated CCl4-induced hepatic fibrosis in rats through pharmacological mechanisms that involved manifold targets and pathways, including aliphatic acid synthesis and metabolism pathways and the AMPK signaling pathway. This study provided a reference and basis for further research and clinical utilization of YYHXD.