[Compensatory reaction of the ascending colon following jejuno-ileal bypass. Experimental study]

The series of physiopathologic consequences and the adaptive response that appears in the residual intestine following intestinal by-pass surgery has been widely studied. The same is not true for the ascending colon. Having demonstrated the adaptive changes this organ undergoes after a massive enterectomy, we carried out the present study to evaluate the compensatory reaction after an intestinal by-pass. A total of 115 Wistar rats weighing 350-550 g were used. Twenty animals made up group 0 (control), 30 underwent intestinal section (group II) and 65 received a jejuno-ileal by-pass (group III), with latero-lateral anastomosis. After weight control was performed the animals were sacrificed at 15, 30, 45 and 60 days, and samples were taken from the ascending colon for optical microscopy (OM), scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM). All objective data were quantified and statistical studies carried out. The by-pass animals showed statistically significant ponderal drops (p less than 0.001), an expression of the malabsorption disorder the by-pass produced. Groups 0 (control) and I (IS) showed no macroscopic, microscopic or ultrastructural changes. The by-pass animals, however, manifested colic dilatation with a significant increase in thickness, to the detriment of the muscularis and mucosa, and greater crypt depth with a relative decrease in the number of goblet cells. Enterocytes increased in number and size. These changes were statistically significant in relation to groups 0 and I. The above findings were confirmed ultrastructurally. In the scanning electronic microscopy after 30 days, the colic mucosa had an irregular appearance, with elevations but no foliated appearance.(ABSTRACT TRUNCATED AT 250 WORDS)