Determination of the Proper Time to De-Epithelialization of Ileal Segment Using Enzyme in Dog
Augmentation of the bladder with bowel was first described by Mikulicz at the turn of the century. Despite its success, there are numerous clinically significant problems associated with enterocystoplasty, including electrolyte disturbances, mucus production, and urinary tract infections. We used an enzyme cocktail to de-epithelialize the segment of intestine prior to augmentation cystoplasty. Success with this procedure suggests: (1) this surgical animal model is applicable for investigating augmentation cystoplasty, and (2) this procedure could theoretically have applications to human surgery.
Materials and methods
Ileocystoplasty was performed on 15 female Persian mixed breed dogs ranging from 12 to 24 months old and weighing between 15 to 24 kg. Twenty centimeters of ileal segment with an adequate mesentery was selected. Five millimeters of ileal segment was taken for normal histological study of intestine. Enzymatic treatment of ileal segment using 0.125% collagenase and trypsin cocktail in 5, 10, 15, 20 and 25 minutes was performed on dogs. After each enzymatic exposure, tissue samples (5 mm) were taken for histopathologic evaluation.
Microscopical study of 180 histologic sections showed that 5 minutes treatment (MT) focally denuded 20% of villi epithelium while 10 MT has caused 33% of villi epithelium de-nudation along with partially crypt lysis. In 15 MT approximately 60% of villi were de-epithelialized while 20 MT caused 75% villi de-nudation with more crypt lysis. Complete de-nudation of villi epithelium occurred with 25 MT. A mild edema of intestinal glands was observed in all groups. The lamina properia, stratum compactum, peyer's patches, muscular layers and serosa were intact in all sections except sections on which 25 MT were performed. Mild vascular damage, petechial hemorrhage in the villi apex and villi separations were focally observed in 25 MT.
The results of this preliminary study stated that approximately 25 minutes enzymatic treatment of ileal segment can completely de-epithelialize villi, and also stratum compactum, peyer's patches, muscular layers and serosa were intact (exception of mild damage to lamina properia). Therefore enzymatic de-nudation is recommended for ileocystoplasty.
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