The effect of clostridium difficile Toxins Aand B on ligated rabbit IIeal loop and cultured cell link BK

clostridium difficile has been recognized as the major cause of pseudomembranous colitis.this bacterium produces two toxins(an enterotoxin -cytotoxin and a potent cytotoxin called toxin A and toxin B erespectively).these toxins have implicated in pathogenesis of the disease.however,histopathological effects of their molecular mass less than 100KDa have been essayed.in the persent study,we examined the dose repsonse and time course of these toxins in ligated rebbit ileal loop and cell culture link BK (boving kidney).the 1-10 mg/ml toxin A, with molecullar weight of 25 KDa,in ligated rabbit ileal loop(6 rabbits with maximum of 15 loopes in each animals) showed a series of histopathological changes leading to inflammation,fluid or bloody fluid accumulation,mucous and villi disraotion in lammina properia.different concentration of toxin B(MW=60 KDa) had no effect on fluid accumulation in striped rabbit ileal loop but caused driness and necrosis intensively.cultured cells exposed to 1mg/ml toxin B showed a series of cytopathologic changes  leading to cell retraction and rounding accompanied by the marginalization of the cell membrane.Enhancement of toxin concentration caused increament of cytopathic effects.