Кишечная стенка при острой ишемии: данные прижизненной оптической когерентной томографии и гистологического анализа

Abstract

The objective is to study the morphometric signs of small bowel ischemic damage basing on intravital optical coherence tomography data and further histological analysis Materials and methods. The study was carried out on male Wistar rats with the use of two models of acute intestinal ischemia: acute occlusive mesenteric ischemia by а. jejunales ligation (group “I”) and acute arteriovenous ischemia by a small bowel loop and frill strangulation together with а. et v. jejunales (group “II”). The state of intramural vessels in vivo was evaluated with the use of optical coherence angiography (OCA). After the macroscopic signs of non-viability appeared the bowel was resected and its stepwise histological analysis was carried out. Results. Ischemic damage development in group “I” was accompanied by decrease of bowel wall thickness by 34,8-42,4% (p=0,032) due to submucous layer destruction - based on histological analysis data and also by decrease of total length of functioning intramural vessels by 4,6% (p=0,004) - based on OCA data. According to the OCA data in group “II” the length of functioning vessels decreased by 89,6%in the strangulated bowel loop and by 6,1% in adducent and abducent sections (p=0,001). In the strangulated loop histological specimens sharply dilated thrombosed veins were seen in all layers of bowel wall, seromuscular layer oedema and diapedesis hemorrhages of mucous coat also took place as well as bowel wall thickening by 25,2% in comparison with the intact one. Conclusions. Сomplex analysis of in vivo optical coherence tomography results and further histological analysis of ischemic small bowel wall made it possible to determine the morphological manifestations which are specific for arterial and arteriovenous mesenteric blood flow disorder. In cases of mesenteric artery occlusion hypoperfusion and mucous coat ischemia are predominant among pathogenetic mechanisms of bowel wall alteration. In the strangulated bowel the main factor of destruction and necrosis is acute insufficiency of venous outflow.