Pothoulakis C, Kelly C P, Joshi M A, Gao N, O'Keane C J, Castagliuolo I, Lamont J T
Evans Memorial Department of Clinical Research, University Hospital, Boston University School of Medicine, Massachusetts.
Gastroenterology. 1993 Apr;104(4):1108-15. doi: 10.1016/0016-5085(93)90280-p.
Saccharomyces boulardii is a nonpathogenic yeast used for the prevention and treatment of Clostridium difficile-associated diarrhea and colitis. However, the mechanism by which S. boulardii exerts its protective effects remains unclear.
The binding of [3H]toxin A to its brush border receptor preincubated with S. boulardii-cultured suspension or filtered conditioned medium was measured in vitro. The effect of toxin A on secretion, epithelial permeability, and morphology in rat ileal loops in vivo was also examined in rats pretreated with S. boulardii.
S. boulardii reduced [3H]toxin A-receptor binding in a dose-dependent fashion. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of ileal brush border exposed to S. boulardii-conditioned medium revealed a diminution of all brush border proteins. Treatment of rats with S. boulardii suspension reduced fluid secretion and mannitol permeability caused by toxin A.
S. boulardii may reduce some of the enterotoxic effects of toxin A by inhibiting toxin A-receptor binding. This effect appears to be manifested by a secreted product of the yeast, possibly a protease.
布拉氏酵母菌是一种非致病性酵母，用于预防和治疗艰难梭菌相关性腹泻和结肠炎。然而，布拉氏酵母菌发挥其保护作用的机制仍不清楚。
在体外测量[3H]毒素A与预先用布拉氏酵母菌培养悬液或过滤后的条件培养基孵育的刷状缘受体的结合。在用布拉氏酵母菌预处理的大鼠中，还检测了毒素A对体内大鼠回肠襻分泌、上皮通透性和形态的影响。
布拉氏酵母菌以剂量依赖的方式降低了[3H]毒素A-受体的结合。暴露于布拉氏酵母菌条件培养基的回肠刷状缘的十二烷基硫酸钠聚丙烯酰胺凝胶电泳显示所有刷状缘蛋白减少。用布拉氏酵母菌悬液处理大鼠可减少毒素A引起的液体分泌和甘露醇通透性。
布拉氏酵母菌可能通过抑制毒素A-受体结合来降低毒素A的一些肠毒素作用。这种作用似乎由酵母的一种分泌产物（可能是一种蛋白酶）表现出来。
