Lipid-Lowering Effects of Lactobacillus fermentum CQPC04 in C57BL/6J Mice

Probiotics, as functional dietary components, can effectively regulate lipid metabolism and promote health. This study investigated Lactobacillus fermentum CQPC04 (LF-CQPC04), a strain isolated from traditional naturally fermented Sichuan pickles, to examine its lipid-lowering effects and underlying mechanisms in mice. Sixty 6-week-old C57BL/6J mice were randomly divided into six groups, with 10 mice in each group and were fed a high-fat diet and administered different doses of LF-CQPC04 for 8 weeks. Their weight, food intake, and water intake were recorded daily. Histopathological, biochemical, immunological, and molecular analyses were performed. The results demonstrated that LF-CQPC04 significantly suppressed abnormal body weight gain and visceral index increases induced by a high-fat diet. It also reduced serum levels of triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), aspartate transaminase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (AKP), while increasing high-density lipoprotein cholesterol (HDL-c). Furthermore, LF-CQPC04 lowered the concentrations of pro-inflammatory cytokines such as interleukin-6 (IL-6), interleukin-1β (IL-1β), tumour necrosis factor-alpha (TNF-α), and interferon-gamma (IFN-γ), and elevated anti-inflammatory cytokines IL-4 and IL-10 in the serum of high-fat diet-fed mice. Real-time quantitative polymerase chain reaction (RT-qPCR) and western blot analyses revealed that LF-CQPC04 downregulated the expression of peroxisome proliferator-activated receptor gamma (PPAR-γ) and CCAAT/enhancer-binding protein alpha (C/EBP-α) at both mRNA and protein levels in liver tissues. Conversely, it upregulated the expression of copper/zinc superoxide dismutase (Cu/Zn-SOD), manganese superoxide dismutase (Mn-SOD), catalase (CAT), cholesterol 7α-hydroxylase (CYP7A1), PPAR-α, carnitine palmitoyltransferase 1 (CPT1), lipoprotein lipase (LPL), and ATP-binding cassette transporter A1 (ABCA1). Notably, LF-CQPC04 exhibited stronger lipid-regulating effects compared to both L-carnitine and commercial Lactobacillus delbrueckii subsp. bulgaricus (LB). In conclusion, LF-CQPC04 demonstrates beneficial lipid-lowering properties and possesses promising probiotic potential. However, this study was limited to in vivo experiments, and it lacks corresponding cell experiments to verify the molecular mechanism and human experiments to verify the effect. Future studies will incorporate both cellular and human experiments to more comprehensively validate the lipid-lowering effects and mechanistic actions of LF-CQPC04.