Brouillard M Y, Rateau J G
Faculté de Médecine Saint-Antoine, Laboratoire d'Histologie, Paris.
Gastroenterol Clin Biol. 1989 Jan;13(1):18-24.
The use of clays in the treatment of enterocolitis is justified by their ability to adsorb viruses, biliary acids and bacterial toxins secreted into the intestinal lumen. We have studied the in vitro inactivation of the LT toxins of Vibrio cholerae and E. coli, the ST toxin of ETEC and the verotoxin of EHEC. These various toxins were incubated with two types of clays, smectite and kaolin, to investigate the influence of dose, pH variations and the duration of contact of the clays with the toxins. Irrespective of their presence or absence in the supernatant, the biological activity of the toxins was assessed in cell culture and in the newborn mouse test. Both clays inactivated the LT toxin. Smectite was more efficient than kaolin as it was active immediately especially at the pH of intestinal chyme. The LT toxins were adsorbed on the clays by hydrogen bonding. This permitted the segregation of the toxins and prevented them from being fixed to the membrane receptors on the cells. The two clays were ineffective against the verotoxin of EHEC when the pH was alkaline although they were more efficient at acid pH. ST toxin of ETEC was slightly adsorbed by smectite and kaolin.
黏土用于治疗小肠结肠炎是合理的，因为它们能够吸附分泌到肠腔内的病毒、胆汁酸和细菌毒素。我们研究了霍乱弧菌和大肠杆菌的不耐热毒素（LT毒素）、产肠毒素大肠杆菌（ETEC）的耐热毒素（ST毒素）以及肠出血性大肠杆菌（EHEC）的志贺毒素在体外的失活情况。将这些不同的毒素与两种黏土（蒙脱石和高岭土）一起孵育，以研究剂量、pH变化以及黏土与毒素接触时间的影响。无论上清液中是否存在毒素，都在细胞培养和新生小鼠试验中评估毒素的生物活性。两种黏土都能使LT毒素失活。蒙脱石比高岭土更有效，因为它立即就有活性，尤其是在肠糜的pH值条件下。LT毒素通过氢键吸附在黏土上。这使得毒素分离，并阻止它们与细胞上的膜受体结合。当pH为碱性时，这两种黏土对EHEC的志贺毒素无效，尽管它们在酸性pH条件下更有效。ETEC的ST毒素被蒙脱石和高岭土轻微吸附。
