Inhibitory effects of Lactobacillus fermentum TKSN02 isolated from Xinjiang cheese on obesity induced by high-fat diet in mice and its gut microbiota modulation effects

Abstract This study aimed to investigate the anti-obesity effects of Lactobacillus fermentum TKSN02 and its role in modulating gut microbiota. Biochemical assays, tissue section analysis, and qPCR were employed to evaluate serum and tissue parameters in mice. Additionally, mRNA expression of specific microorganisms in fecal samples was measured to assess changes in gut microbiota composition. The results demonstrated that both L-carnitine and L. fermentum TKSN02 significantly reduced body weight in obese mice. These treatments also decreased liver and epididymal fat organ indices, and lowered serum and hepatic levels of ALT, AST, AKP, TC, TG, and LDL-C. Meanwhile, they increased HDL-C levels, as well as fecal contents of TC, TG, and total protein (TP). H&E staining revealed that L-carnitine and L. fermentum TKSN02 ameliorated obesity-induced liver tissue damage and reduced adipocyte hypertrophy and accumulation. qPCR analysis further indicated that both interventions upregulate the mRNA expression of CPT-1, LPL, PPAR-α, and CYP7A1, while downregulating PPAR-γ and C/EBPα in the liver of high-fat diet-fed mice. Moreover, they promoted the abundance of Bacteroidetes, Lactobacillus , and Bifidobacterium , but suppressed Firmicutes in the gut microbiota. Together, these results suggest that L-carnitine and L. fermentum TKSN02 exert anti-obesity effects, with the high-dose L. fermentum TKSN02 (TKSN02H) showing the most pronounced outcomes. In conclusion, L. fermentum TKSN02 may help control obesity by positively modulating gut microbiota.