植物乳杆菌ST-Ⅲ菌株降胆固醇作用的研究

Studies on cholesterol removal by Lactobacillus plantarum ST-Ⅲ strain

ST-Ⅲ菌株是经体外体内实验证实的具有降低胆固醇功能的一株植物乳杆菌,本实验对其体外降胆固醇机理进行了研究。结果表明,植物乳杆菌ST-Ⅲ菌株是通过同化作用和沉淀作用来共同降低胆固醇,其中同化作用为主导作用,可降低胆固醇76.38μg/mL(25.5%);沉淀作用为辅助作用,可降低胆固醇44.62μg/mL(14.85%);并且沉淀作用和pH值具有相关性,在控制pH6.0和不控制的条件下,分别为29μg/mL与41μg/mL,这表明在酸性条件下ST-Ⅲ菌株的沉淀作用更易发生。在抗超声破碎实验中发现添加有胆固醇培养的ST-Ⅲ菌株抗超声能力明显高于对照的ST-Ⅲ菌株,这有可能是胆固醇进入到细胞膜中改变其结构增强韧性所致;在细胞荧光标记检测实验中也发现了胆固醇能改变细胞膜的组成成分,导致通透性变化,添加有胆固醇培养的ST-Ⅲ菌株荧光强度为106.22,仅为对照组的15.1%。

LactobaciUus plantarum ST-Ⅲ strain was proved to be able to remove cholesterol in vitro and in vivo. The study on the mechanism of cholesterol removal in vitro was carried out. The results showed that ST-Ⅲ strain was able to precipitate and assimilate cholesterols accounting for 44.62μg/mL（14.85 %） and 76.38μg/mL（25.5 %） respectively, which displayed assimilation as the predominant one. And there was a correlation between the precipitation and pH values, under the condition of pH control and without control, 29μg/mL and 41μg/mL were precipitated respectively, illustrated that precipitation happened more easily under the acidity condition. Cells cultured in the presence of cholesterol were more resistant to ultrasonication than those cultured in control group, suggesting a possible alteration of the cell wall or membrane. The cholesterol restrained the permeability of cell wall or membrane through fluorescent labeling was found. The fluorescence of ST-Ⅲ strain cultured in the presence of cholesterol was much lower than others, only 15.1% versus the control one.