HUMSCs repair CCl₄-induced chronic liver injury in rats via metabolic regulation

To explore the therapeutic effects of human umbilical cord mesenchymal stem cells (HUMSCs) on repairing CCl₄-induced chronic liver injury in rats via intravenous injection and to identify the associated key metabolites.

Cell experiments: THLE-2 cells were divided into blank control, CCl₄-treated, and CCl₄ + Exos groups. Cell viability was assessed using the CCK-8 assay, while levels of AST, ALT, and MDA were determined using commercial kits. Targeted metabolomics analysis was employed to identify differentially expressed metabolites. Transmission electron microscopy (TEM) was used to evaluate mitochondrial morphology, and immunofluorescence staining was performed to examine the colocalization of Exos with mitochondria. Animal experiments: 24 healthy SPF SD rats were randomly divided into healthy, CCl₄, and CCl₄ + HUMSCs groups (n = 8 per group). Serum samples were collected for biochemical detection and targeted metabolomics analyses, while liver tissues underwent histopathological examination. Immunofluorescence staining was employed to monitor HUMSCs enrichment.

In the CCl₄ + Exos group, cell viability was significantly restored, and the elevated levels of AST, ALT, and MDA were reversed, while mitochondrial ultrastructure was ameliorated with successful Exos-mitochondria colocalization. Targeted metabolomics confirmed the presence of differentially expressed metabolites exhibiting consistent trends in both cellular and animal models. In the animal study, the CCl₄ group showed significant liver dysfunction and hepatic pathology characterized by hepatocyte steatosis and fibrous tissue hyperplasia. In contrast, the CCl₄ + HUMSCs group demonstrated markedly improved liver function and reduced pathological changes. Biochemical analysis revealed significant differences in ALT, AST, ALB, TBIL, TP, UREA, CR, and UA levels between the CCl₄ + HUMSCs and CCl₄ groups. Serum metabolomics analysis showed that compared with the CCl₄ group, 1,7-Dimethylxanthine and Xanthosine were significantly upregulated, while Succinic Acid, (S)-2-Hydroxybutanoic Acid, oxidized glutathione, and 3'-Sialyllactose were significantly downregulated in the CCl₄ + HUMSCs group.

HUMSCs treatment significantly reduced hepatic steatosis and fibrosis compared with the CCl₄ group alone. Metabolomic analysis suggests that the underlying mechanisms may involve upregulation of propanoate metabolism and increased taurochenodeoxycholic acid levels, which warrant further investigation.