Effect of Lactobacillus brevis 119-2 isolated from Tsuda kabu red turnips on cholesterol levels in cholesterol-administered rats

In a previous in vitro study, we reported that the potential mechanism of the cholesterol-lowering effect of Lactobacillus brevis 119-2 isolated from turnip Tsuda kabu was the incorporation of cholesterol to cell membrane. In this study, we analyzed serum cholesterol and hepatic gene expression of Sprague-Dawley (SD) rats kept on a cholesterol diet with or without L. brevis 119-2 for 2 weeks, to evaluate the cholesterol-lowering effect in vivo. Serum cholesterol levels were significantly reduced in SD rats kept on a diet including L. brevis 119-2 compared with that in SD rats kept on a diet without L. brevis 119-2, and both viable and dead L. brevis 119-2 induced this effect. Hepatic gene analysis by DNA microarray suggested that the potential mechanism of the cholesterol-lowering effect of L. brevis 119-2 in vivo was inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase activity by insulin induced gene (Insig) protein, and induction of catabolism of cholesterol to bile acid by Cyp7a1 (cytochrome P450 a1). In addition, we found that inclusion of L. brevis 119-2 in the diet decreased serum low density lipoprotein (LDL) cholesterol levels by inducing overexpression of the LDL receptor gene. In contrast, Lactobacillus acidophilus ATCC 43121 increased high density lipoprotein cholesterol levels by inducing overexpression of the ATP-binding cassette sub-family. A member 1 (Abca1) and Angiopoietin-like 3 (Angptl3) genes. These results suggest that L. brevis 119-2 decreases the risk of atherosclerosis by lowering serum cholesterol, ameliorating the effect of fatty liver.