Central Research Laboratory, Second Hospital of Jilin University, Changchun, PR China.
PLoS One. 2013 Jul 22;8(7):e69868. doi: 10.1371/journal.pone.0069868. Print 2013.
The objective of this study was to evaluate the functional properties of lactic acid bacteria (LAB) isolated from Tibetan kefir grains. Three Lactobacillus isolates identified as Lactobacillus acidophilus LA15, Lactobacillus plantarum B23 and Lactobacillus kefiri D17 that showed resistance to acid and bile salts were selected for further evaluation of their probiotic properties. The 3 selected strains expressed high in vitro adherence to Caco-2 cells. They were sensitive to gentamicin, erythromycin and chloramphenicol and resistant to vancomycin with MIC values of 26 µg/ml. All 3 strains showed potential bile salt hydrolase (BSH) activity, cholesterol assimilation and cholesterol co-precipitation ability. Additionally, the potential effect of these strains on plasma cholesterol levels was evaluated in Sprague-Dawley (SD) rats. Rats in 4 treatment groups were fed the following experimental diets for 4 weeks: a high-cholesterol diet, a high-cholesterol diet plus LA15, a high-cholesterol diet plus B23 or a high-cholesterol diet plus D17. The total cholesterol, triglyceride and low-density lipoprotein cholesterol levels in the serum were significantly (P<0.05) decreased in the LAB-treated rats compared with rats fed a high-cholesterol diet without LAB supplementation. The high-density lipoprotein cholesterol levels in groups B23 and D17 were significantly (P<0.05) higher than those in the control and LA15 groups. Additionally, both fecal cholesterol and bile acid levels were significantly (P<0.05) increased after LAB administration. Fecal lactobacilli counts were significantly (P<0.05) higher in the LAB treatment groups than in the control groups. Furthermore, the 3 strains were detected in the rat small intestine, colon and feces during the feeding trial. The bacteria levels remained high even after the LAB administration had been stopped for 2 weeks. These results suggest that these strains may be used in the future as probiotic starter cultures for manufacturing novel fermented foods.
本研究旨在评估从西藏开菲尔粒中分离出的乳酸菌（LAB）的功能特性。从对酸和胆汁盐具有抗性的三种乳杆菌分离株中鉴定出嗜酸乳杆菌 LA15、植物乳杆菌 B23 和发酵乳杆菌 D17，用于进一步评估其益生菌特性。这 3 种选定的菌株对 Caco-2 细胞的体外黏附率较高。它们对庆大霉素、红霉素和氯霉素敏感，对万古霉素耐药，MIC 值为 26 µg/ml。所有 3 种菌株均表现出潜在的胆盐水解酶（BSH）活性、胆固醇同化能力和胆固醇共沉淀能力。此外，还在 Sprague-Dawley（SD）大鼠中评估了这些菌株对血浆胆固醇水平的潜在影响。4 个治疗组的大鼠分别用以下实验饮食喂养 4 周：高胆固醇饮食、高胆固醇饮食加 LA15、高胆固醇饮食加 B23 或高胆固醇饮食加 D17。与未添加 LAB 的高胆固醇饮食喂养的大鼠相比，LAB 处理组大鼠的血清总胆固醇、甘油三酯和低密度脂蛋白胆固醇水平显著降低（P<0.05）。B23 和 D17 组的高密度脂蛋白胆固醇水平显著高于对照组和 LA15 组（P<0.05）。此外，LAB 给药后粪便胆固醇和胆汁酸水平均显著升高（P<0.05）。LAB 处理组大鼠粪便乳杆菌计数显著高于对照组（P<0.05）。此外，在喂养试验期间，这 3 种菌株均在大鼠小肠、结肠和粪便中被检测到。即使在停止 LAB 给药 2 周后，细菌水平仍保持较高水平。这些结果表明，这些菌株未来可能被用作新型发酵食品制造的益生菌起始培养物。
