Vascular Pathology of Ischemia/Reperfusion Injury of Rat Small Intestine.

Ischemia/reperfusion (I/R) injury of the small intestine caused by occlusion of the superior mesenteric artery affects the intestinal tissue as well as components of the blood circulatory system from the microvasculature to mesenteric vessels. The aim of this work was to study the correlation between the dynamics of destruction development in the intestinal tissue, microvasculature, and mesenteric vessels in I/R of the small intestine. The microvasculature was analyzed by whole-organ continuous monitoring of the intestinal mucosal blood perfusion by laser Doppler flowmetry during the entire I/R. Real-time RT-PCR was used to assess gene expression of NF-κB, caspase-3, Ki67, and TNF-α in blood vessels. At the start of reperfusion, the first targets to be disrupted are microvessels in the apical villi. Injury of the apical part of the microcirculatory bloodstream correlates with the reduction in intestinal mucosal blood perfusion, which occurred simultaneously with apical villous destruction. By the end of the reperfusion period, the low intestinal mucosal blood perfusion is mirrored by the destruction of the microvasculature and mucosal structures in the entire organ. The development of mesenteric vessel injury is characterized by a change in NO metabolism and damaged endothelial cells concomitant with an alteration in the expression of genes encoding NF-κB, caspase-3, and Ki67 by the end of the reperfusion period. In I/R injury, detrimental effects on the intestinal tissue, microvasculature, and mesenteric vessels develop and exhibit common mechanisms of function, which show strong correlations.