Lactobacillus plantarum KFY02 from Naturally Fermented Yoghurt Alleviates High-Fat Diet–Induced Obesity in Mice via PPAR-α/γ Signalling

Obesity is a chronic metabolic disease which is caused by many reasons, and the fundamental difference lies in that energy ingestion and consumption are unbalanced. Lactobacillus species have been reported to improve gut health, enhance nutrient absorption, lower serum cholesterol, regulate toxins, and inhibit the growth of harmful intestinal bacteria. In this study, Lactobacillus plantarum KFY02 (LP-KFY02), a novel strain isolated from Xinjiang fermented Yoghurt, was evaluated for its lipid-lowering effects in an in vivo animal model. Obesity was induced in mice using a high-fat diet (HFD). Serum and tissue samples were subsequently analysed via molecular biological assays. The results demonstrated that LP-KFY02 significantly suppressed the HFD-induced increase in organ indices. Furthermore, LP-KFY02 reduced serum and hepatic levels of alkaline phosphatase (AKP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C), while enhancing high-density lipoprotein cholesterol (HDL-C) levels in obese mice. Histopathological examination revealed that LP-KFY02 alleviated obesity-related liver injury and reduced adipocyte enlargement in mouse tissues. Quantitative PCR results indicated that LP-KFY02 up-regulated the mRNA expression of lipoprotein lipase (LPL), peroxisome proliferator-activated receptor α (PPAR-α), cholesterol 7α-hydroxylase (CYP7A1), and carnitine palmitoyltransferase 1A (CPT1A) in both liver and epididymal adipose tissues, while down-regulating the expression of peroxisome proliferator-activated receptor γ (PPAR-γ) and CCAAT/enhancer-binding protein α (C/EBP-α). Additionally, enzyme-linked immunosorbent assay (ELISA) results showed that LP-KFY02 markedly decreased serum levels of the pro-inflammatory cytokines interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α), IL-1β, and interferon-γ (IFN-γ), and increased levels of the anti-inflammatory cytokines IL-4 and IL-10. In summary, LP-KFY02 effectively ameliorated HFD-induced obesity, exhibiting efficacy comparable to commercially available L-carnitine and superior to the commonly used industrial strain Lactobacillus delbrueckii subsp. bulgaricus. These findings suggest that LP-KFY02 is a health-promoting strain with considerable probiotic potential.