Network Pharmacology and Serum Nontargeted Metabolomics Reveal the Protective Effects of Propionate Against Liver Damage Induced by a High-Fat and AGE-Rich Diet in Diabetic Mice.

Abstract

Diabetic liver injury is a leading cause of mortality in diabetes, with no specific treatment available. Sodium propionate (NaP) has anti-inflammatory and antioxidant properties, but its effectiveness in treating diabetic liver injury is still lacking research. The study employed network pharmacology to identify potential targets of NaP for Type 2 diabetes treatment, using oleic acid (OA) and advanced glycation end products (AGEs) to induce diabetic liver injury in HepG2 cells in vitro. Post-NaP intervention, Oil Red O staining assessed cellular lipid deposition, while Western blotting analyzed protein expression associated with oxidative stress, autophagy, and bile acid synthesis. NaP was administered to mice with diabetic liver injury induced by a high-fat and AGEs diet, and qPCR analysis was conducted to assess the expression of genes associated with inflammation, oxidative stress, and bile acid synthesis in the liver. HE staining was used to observe the liver injury, and nontargeted metabolomics analysis was used to analyze the effect of NaP on serum metabolic pathways. Network pharmacology analysis showed that NaP has anti-inflammatory and antioxidant effects, mainly involving multiple targets such as mitochondrial function, insulin resistance, and glucose metabolism. Experimental results in cells and animals demonstrated that NaP reduces lipid accumulation and inflammation in liver cells; decreases inflammatory markers like NLRP3, IL-1β, and TNF-α; enhances antioxidant factors such as serum SOD and liver Nrf2; increases the expression of the bile acid synthesis enzyme CYP7A1; and upregulates autophagy in liver cells. Serum nontargeted metabolomics indicated that NaP enhances anti-inflammatory and antioxidant metabolites, including proline and N-Acetyl-L-leucine, in diabetic liver injury mice. It potentially influences purine metabolism, amino acid synthesis (e.g., arginine, tryptophan, and tyrosine), and steroid hormone biosynthesis. This study indicates that NaP may serve as a preventive and therapeutic agent for diabetic liver injury.