益生菌抑制大肠埃希菌K1株黏附与侵袭的实验研究

目的评价三联活菌片中的益生菌对大肠埃希菌K1株在肠上皮黏附和侵袭的抑制作用。方法将大肠埃希菌K1株与Lovo细胞共孵育,采用黏附性抑制和竞争性排除方法,检测大肠埃希菌K1株黏附侵袭于Lovo细胞的数量,并采用流式细胞术分析益生菌对大肠埃希菌K1株诱导的细胞凋亡的抑制作用。将Sprague Dawley乳鼠随机分为实验组（益生菌和致病菌）与对照组（致病菌）。应用活菌计数法,对各组乳鼠肠道和血液中大肠埃希菌K1株进行定量检测,观察益生菌对大肠埃希菌K1株血行转移的拮抗作用。结果益生菌在体外能显著抑制大肠埃希菌K1株黏附侵袭于Lovo细胞（P〈0.01）,其抑制作用呈剂量依赖性;益生菌能显著降低大肠埃希菌K1株诱导的细胞凋亡（P〈0.01）;益生菌能显著抑制大肠埃希菌K1株的生长与血行转移,患菌血症的乳鼠数量显著降低（P〈0.01）。结论三联活菌片中益生菌能显著抑制大肠埃希菌K1株对肠上皮的黏附损伤和血行转移。

Inhibition of the Adherence and Invasion of E. coli K1 by Probiotics

Objective To evaluate inhibitory effect of probiotics in the adherence and invasion of Escherichia coli K1 to murine intestinal mucosa. Methods Viable bacterial counting method was applied to determine the number of Escherichia coli K1 adhered and invaded into Lovo cells treated with probiotics. FCM analysis was used to analyze probiotics-mediated inhibition of E. coli-induced apoptosis of Lovo cells. Neonatal rats were randomly assigned to the following experimental groups：probiotics ＋ pathogen treatment group and pathogen treatment group. Viable cell counting method was used to quantitatively determine the number of pathogens （Escherichia coli K1） in the intestine of rats receiving orally administration of probiotics. Results Probiotics were found to competitively suppress the adherence and invasion of E. coli to Lovo cells in a dose-dependent manner （P0.01）. The level of apoptosis of Lovo cells was also decreased （P0.01）. The number of intestinal E. coli and the degree of bacteremia was also decreased in rats with probiotics treatment （P0.01）. Conclusion Probiotics could protect intestinal epithelial cells and inhibit the adherence of pathogens to the intestinal epithelium.