Ischemia-reperfusion histopathology alterations of the rabbit intestinal wall with and without ischemic preconditioning

Abstract

. Provided institutional support for the research development. ABSTRACT Purpose:To evaluate the histopathology alterations of the intestinal mucosa of rabbits submitted to mesenteric artery ischemia and reperfusion with and without ischemic preconditioning. Methods: Two groups of ten male New Zealand white rabbits body (weight 2.2-3.0, average 2.5 kg). For mesenteric ischemia induction in all animals the small bowel and mesentery were cut 30cm and 60cm far from the gastroduodenal pyloric transition before the proximal mesenteric artery occlusion. In the Group 1 animals, the proximal mesenteric artery was occluded for 45 min with an atraumatic vascular clamp, followed by reperfusion for 30 min. In the Group 2 the 45 min ischemic phase was preceded by three cycles of ischemia (2 minutes each) alternated with three cycles of reperfusion (2 minutes each). For istopathology study small bowel biopsies were obtained before ischemia (control), after 45 min of mesenteric ischemia and at 30 min. of mesenteric artery reperfusion. Results: In the Group I animals, the followings histopathology grade results were observed: t1, mean 2,8; t2, mean 3,3. Using the Kruskal-Wallis non-parameter test, differences between t0 and t1 and t0 and t2 were significants (p<0.05), but not significant between t1 and t2 (p>0.05). In the Group 2 animals histopathology grade results were: t1 mean 2,6 and t2, mean 2,1. Differences between t0 and t1, t0 and t2 were significant (p<0.05). It was not observed differences (p>0.05) between results of t1 in both groups but histopathology injury observed in Group 1 t2 biopsies were higher (p<0.05) than observed in the same period (t2) of Group 2 animals. Conclusion: Microscopic examination of the biopsies revealed significant evidence of preconditioning protection against small bowel wall ischemia-reperfusion injury. Key words: Mesenteric Vascular Occlusion. Ischemic Preconditioning. Animal Experimentation. Rabbits. RESUMOObjetivo: Avaliar as alterações histopatológicas da mucosa intestinal de coelhos submetidos a isquemia-reperfusão com e sem precondicionamento isquêmicol. Métodos: Foram estudados dois grupos de dez coelhos Nova Zelândia machos com pesos variáveis entre 2,2 e 3,0 kg (média de 2,5 kg) de peso corpóreo. Para indução da isquemia, em todos os animais, o intestino delgado e o mesentério foram seccionados 30 cm e 60 cm após a transição pilórica gastroduodenal, antes da oclusão da artéria mesentérica cranial. Nos animais do Grupo 1, a artéria mesentérica proximal foi ocluida por pinçamento atraumático durante 45 min., seguido de reperfusão por 30 min. No Grupo 2, foi realizado precondicionamento por três ciclos de 2 min. de oclusão mesentérica intercalados com três ciclos de 2 min. de reperfusão, seguido de oclusão mantida por 45 min e reperfusão de 30min. como no Grupo I. Para estudo histopatológico, foram obtidas biópsias da parede intestinal antes da isquemia (t 0 -controle), após 45 min. de isquemia (t 1 ) e após 30 min. de reperfusão (t 2) . Resultados: No Grupo I foram observados os segu...

Ischemia and reperfusion of rat small intestine using pentoxyfilline and prostaglandin E1

“…To repair this special area it is mandatory a tissue reperfusion. If this subtle interruption occurs partially or in the whole small intestine, with a high intensity, many times it is not possible to maintain even the basal metabolism and, consequently, there is cell death and tissue necrosis [1][2][3][4] . The intestinal mucosa in the small intestine, it is the first area to be severely affected in cases of ischemia.…”

“…The intestinal mucosa in the small intestine, it is the first area to be severely affected in cases of ischemia. An ischemia with more than one hour duration could produce edema at submucosa, followed by loosening of the superficial mucosa and it could produce ulcers and/or bleeding in the intestinal villous [3][4][5] . It is well known that ischemia could cause tissue necrosis but if a reperfusion is done the blood flow could be reestablished, as well as recovery of tissue oxygenation in the area, bringing indispensable nutrients to tissue repair.…”

“…However and paradoxally the liberation of free radicals could increase the local lesions and provoke lesions far away from the ischemic area. Therefore, the histopathological tissue alterations consequent to blood flow deprivation would be detected microscopically, by light microscopy or by imunohistochemical techniques, showing tissue alterations in the area submitted to ischemia and reperfusion 3,4 .…”

Hystopathological study of the intestinal epithelium submitted to different times of programmed ischemia and twenty four hours reperfusion

“…In addition to the qualitative and quantitative histopatological changes already observed, several studies showed biochemical and inflammatory alterations after ischemia and specially reperfusion 14,27,[37][38][39][40] Some authors think that the preconditioning protection revealed significant evidence against small bowel wall of ischemia-reperfusion injury and attenuate the permeability of the small intestines after limb ischemia-reperfusion. The protective mechanism of ischemic post-conditioning may be related to inhibition of oxygen free radicals and inflammatory cytokines that cause organ damage [41][42][43][44][45] .…”