Lactiplantibacillus plantarum from Thai fermented pork with inulin ameliorates metabolic disturbances through proteomic mechanisms

This study investigated the molecular mechanisms by which Lactiplantibacillus plantarum strain P4, isolated from Thai fermented pork (Nham), affects high-fat diet-induced metabolic alterations in rats, alone and combined with inulin. Male Sprague-Dawley rats (n = 32, initial weight 204.12 ± 4.80 g) were randomized into four groups (n = 8/group): normal diet (N), high-fat diet (HF), high-fat diet with L. plantarum P4 (HFLac, 10^9 CFU/g), and high-fat diet with both L. plantarum P4 and inulin (HFLacIn, 10^9 CFU/g + 0.1% w/w inulin). After 4 weeks, we analyzed lipid profiles, liver and kidney function markers, inflammatory parameters, and conducted proteomic analysis of liver tissue using high-resolution mass spectrometry. The HF group exhibited distinct protein alterations compared to the N group, indicating dysregulated fatty acid metabolism. The synbiotic HFLacIn intervention improved multiple parameters: (1) Enhanced lipid profiles with increased HDL-C (15.8%) and reduced LDL-C (9.5%) and VLDL (15.9%); (2) Improved liver function with reduced ALP (3.4%); and (3) Decreased inflammatory markers TNF-α (13.4%) and CRP (31.4%, p = 0.03). Proteomic analysis revealed upregulation of key proteins in the HFLacIn group: long-chain-fatty-acid-CoA ligase 1 (1.25-fold, p = 0.033) for enhanced fatty acid activation, hemopexin (1.04-fold, p = 0.039) for improved oxidative stress protection, and modified inflammation-related proteins. The marked upregulation of histone H2B type 1-A (2.82-fold, p = 0.002) suggests epigenetic modifications contributing to metabolic improvements. These findings provide molecular evidence supporting the therapeutic potential of probiotics from traditional fermented foods, especially when combined with prebiotics, in managing metabolic disorders.