Effects of Lactobacillus fermentum CQPC04 on Lipid Reduction in C57BL/6J Mice

Abstract

Probiotics are functional foods that can effectively regulate lipid reduction and maintain body health. In this study, a strain of Lactobacillus fermentum CQPC04 (LF-CQPC04) isolated from traditional naturally fermented vegetables (Sichuan pickles) was studied, and its effects on lipid reduction in mice, as well as its mechanism of action, were observed. The results of this experiment show that LF-CQPC04 can reduce the abnormal weight gain and abnormal visceral index of mice caused by a high-fat diet. LF-CQPC04 can decrease TG (triglycerides), TC (total cholesterol), LDL-c (low-density lipoprotein cholesterol), AST (aspartate transaminase), ALT (alanine aminotransferase), and AKP (alkaline phosphatase) levels and increase HDL-c (high-density lipoprotein cholesterol) levels in the serum of high-fat mice. LF-CQPC04 can also decrease the levels of inflammatory cytokines, such as IL-6 (interleukin-6), IL-1β (interleukin-1 beta), TNF-α (tumor necrosis factor alpha), and IFN-γ (interferon gamma), and increase IL-4 and IL-10 levels in the serum of high-fat mice. The results of RT-qPCR (real-time quantitative polymerase chain reaction) and western blot experiments show that LF-CQPC04 can also down-regulate the expression of PPAR-γ (peroxisome proliferator-activated receptor gamma), C/EBP-α (CCAAT/enhances binding protein alpha) mRNA, and protein in the liver tissue of high-fat mice, while up-regulating the expression of Cu/Zn-SOD (copper/zinc superoxide dismutase), Mn-SOD (manganese superoxide dismutase), CAT (catalase), CYP7A1 (cholesterol 7 alpha hydroxylase), PPAR-α (peroxisome proliferator-activated receptor alpha), CPT1 (carnitine palmitoyl transferase 1), LPL (lipoprotein lipase), and ABCA1 (ATP-binding cassette transporter A1). Moreover, LF-CQPC04 shows stronger effects in regulating lipid reduction in mice than L-carnitine and commercial LB (Lactobacillus delbrueckii subsp. Bulgaricus) bacteria. LF-CQPC04 is beneficial for lipid reduction in animals and has good probiotic potential.

Keywords: C57BL/6J mice; Lactobacillus fermentum; expression; lipid reduction; oxidation.

FIGURE 1

Morphology of Lactobacillus fermentum CQPC04 (A) and Lactobacillus delbrueckii subsp. Bulgaricus (B).

FIGURE 2

Body weight of mice. LF-CQPC04-L: mice treated with a low concentration of Lactobacillus fermentum CQPC04 (1.0 × 10⁸ CFU/kg); LF-CQPC04-H: mice treated with a high concentration of Lactobacillus fermentum CQPC04 (1.0 × 10⁹ CFU/kg); LB: Mice treated with Lactobacillus delbrueckii subsp. Bulgaricus (1.0 × 10⁹ CFU/kg).

FIGURE 3

Pathological observation of H&E staining in mouse liver (A) and epididymal (B) tissues. LF-CQPC04-L: mice treated with a low concentration of Lactobacillus fermentum CQPC04 (1.0 × 10⁸ CFU/kg); LF-CQPC04-H: mice treated with a high concentration of Lactobacillus fermentum CQPC04 (1.0 × 10⁹ CFU/kg); LB: Mice treated with Lactobacillus delbrueckii subsp. Bulgaricus (1.0 × 10⁹ CFU/kg).

FIGURE 4

The mRNA (A) and protein (B) expression of Cu/Zn-SOD, Mn-SOD, and CAT in liver tissue of mice. ^a–fMean values with different letters in the same column are significantly different (P < 0.05) according to Duncan’s multiple range test. LF-CQPC04-L: mice treated with a low concentration of Lactobacillus fermentum CQPC04 (1.0 × 10⁸ CFU/kg); LF-CQPC04-H: mice treated with a high concentration of Lactobacillus fermentum CQPC04 (1.0 × 10⁹ CFU/kg); LB: Mice treated with Lactobacillus delbrueckii subsp. Bulgaricus (1.0 × 10⁹ CFU/kg).

FIGURE 5

The mRNA (A) and protein (B) expression of PPAR-α, PPAR-γ, CYP7A1, CPT1, LPL, C/EBP-α, and ABCA1 in liver tissue of mice. ^a–fMean values with different letters in the same column are significantly different (P < 0.05) according to Duncan’s multiple range test. LF-CQPC04-L: mice treated with a low concentration of Lactobacillus fermentum CQPC04 (1.0 × 10⁸ CFU/kg); LF-CQPC04-H: mice treated with a high concentration of Lactobacillus fermentum CQPC04 (1.0 × 10⁹ CFU/kg); LB: Mice treated with Lactobacillus delbrueckii subsp. Bulgaricus (1.0 × 10⁹ CFU/kg).

FIGURE 6

The mRNA expression of TNF-α and ZO-1 in colonic tissue of mice. ^a–fMean values with different letters in the same column are significantly different (P < 0.05) according to Duncan’s multiple range test. LF-CQPC04-L: mice treated with a low concentration of Lactobacillus fermentum CQPC04 (1.0 × 10⁸ CFU/kg); LF-CQPC04-H: mice treated with a high concentration of Lactobacillus fermentum CQPC04 (1.0 × 10⁹ CFU/kg); LB: Mice treated with Lactobacillus delbrueckii subsp. Bulgaricus (1.0 × 10⁹ CFU/kg).

FIGURE 7

The mRNA expression in microorganisms in feces of mice. ^a–fMean values with different letters in the same column are significantly different (P < 0.05) according to Duncan’s multiple range test. LF-CQPC04-L: mice treated with a low concentration of Lactobacillus fermentum CQPC04 (1.0 × 10⁸ CFU/kg); LF-CQPC04-H: mice treated with a high concentration of Lactobacillus fermentum CQPC04 (1.0 × 10⁹ CFU/kg); LB: Mice treated with Lactobacillus delbrueckii subsp. Bulgaricus (1.0 × 10⁹ CFU/kg).