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.
Keywords: gene; hypolipidemic; lactic acid bacteria; yak yogurt.
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