Effects of Lactobacillus Casei YBJ02 on Lipid Metabolism in Hyperlipidemic Mice

Abstract Traditionally fermented yak yogurt as a Tibetan dairy product is high not only in nutrients but also in probiotics. A probiotic strain with a potential lipid reducing effect was isolated from yak yogurt. An animal model for hyperlipidemia was evaluated using the blood index and expression levels of lipid metabolism‐related proteins in mice to determine the effect of Lactobacillus casei YBJ02 (LC‐YBJ02) on lipid metabolism in hyperlipidemic mice and the underlying mechanism. LC‐YBJ02 at different concentrations exhibited certain inhibitory effects on the increase in blood lipid in mice. Particularly, high concentrations of LC‐YBJ02 can reduce the cholesterol, triglycerides, and low‐density lipoprotein content; however, no significant effect on the high‐density lipoprotein of the body has been reported. LC‐YBJ02 can effectively increase the reduction in cholesterol level by fecal excretion. In this study, the gene‐affecting mouse obesity was determined using experimental results in mice. The expression levels of peroxisome proliferator‐activated receptor γ (PPARγ), CCAAT enhancer binding protein alpha (CEBP)/α, sterol regulatory element binding protein (SREBP)‐1c, and FAS could improve because of the high‐fat diet in kidney fat. Bacteria at different concentrations could also decrease these expression levels. Specifically, the high concentration of LC‐YBJ02 could suppress the expression of PPARγ, CEBP/α, and SREBP‐1c; however, the expression of FAS was not significantly inhibited. PPARγ and FAS expression levels in the liver were low, but no significant difference was indicated. CEBP/α and SREBP‐1c expression in mouse liver was further detected by Western blot analysis; CEBP/α was considerably low and could not be detected. On the basis of these results, LC‐YBJ02 could be used as probiotics through its lipid reduction effects.