Effect of different periods of hyperbaric oxygen on ischemia-reperfusion injury of rat small bowel

Paulo Roberto Bertoletto,José Carlos Chaves,Anna Tereza Negrini Fagundes,Djalma José Fagundes,Celina Tizuko Fujiyama Oshima,Manuel De Jesus Simões,Ricardo Santos Simões

doi:10.1590/s0102-86502008000100003

Abstract

To determine whether hyperbaric oxygen (HBO) could effectively protect the small intestine mucosa against an ischemic insult, according to different periods of application. The gut of 32 male rats was subjected to 60-min ischemia (clamping the mesenteric artery and vein); After they were further reperfused upon clamp opening during 60 min. Animal groups were as follows. GII = placed on HBO during the ischemia period; GIII = placed on HBO during reperfusion; GIV = treated with HBO throughout the ischemia-reperfusion period. Some animals (GI) did not receive HBO treatment at all and served as reference of ischemia-reperfusion injury (IR). HBO was carried out in a cylindrical acrylic chamber (2.0 ATA). Samples of small bowel were prepared for H.E staining for histological evaluations. The histological injury of mucosa was significantly less when HBO was administered during the ischemia period (17.6 +/- 0.6) as compared with the IR (21.3 +/- 1.8). HBO was not effective when applied during reperfusion (23.1 +/- 2.1) or during the ischemia plus reperfusion period (18.7 +/- 1.9). The thickness of the mucosa was preserved by HBO in ischemia (327.50 +/- 30.23 microm) in comparison with the IR (172.79 +/- 5.95 microm). In the periods of reperfusion (162.50 +/- 6.05 microm) and ischemia plus reperfusion (296.49 +/- 20.01 microm) the mucosa revealed a structural injury. Hyperbaric oxygen affects the ischemic insult of small bowel, being the favorable effect obtained when hyperbaric oxygen was administered early in the ischemic period.

Highlights

Postoperative complications after intestinal transplantation can be ascribed to hypothermic storage and reperfusion injury[1, 2]
In a model with rats subjected to 30 minutes of ischemia followed by 30 minutes of reperfusion it was reported a histologically-evidenced protective effect on the small bowel villi when hyperbaric oxygen (HBO) was applied during the ischemia period[8, 9]
The results showed complete destruction of intestinal villi and hemorrhagic areas in the submucosa in the small bowel of the animals in group I (IR) and group III (HBO during reperfusion)

Summary

Introduction

Postoperative complications after intestinal transplantation can be ascribed to hypothermic storage and reperfusion injury[1, 2]. The small bowel villi are extremely sensitive to ischemia-reperfusion (IR) injury and a number of microcirculatory disturbances contribute to structural and functional changes[1, 3]. A current experimental model induced a controlled intestinal I/R injury in rats by occlusion of a first-order branch of the superior mesenteric artery. The elapsed time of ischemia (minutes to hours), as the ensuing reperfusion time (minutes to hours), are factors handled in different manners[7]. In a model with rats subjected to 30 minutes of ischemia followed by 30 minutes of reperfusion it was reported a histologically-evidenced protective effect on the small bowel villi when HBO was applied during the ischemia period[8, 9]

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