Evaluation of the microcirculation of the equine small intestine following intramural distention and reperfusion

The effects of intraluminal distention (25 cm H₂O, 120 minutes) and subsequent decompression (60 minutes) on the intramural vascular patterns of the equine small intestine was evaluated in 7 anesthetized horses. The vascular system of experimental and control segments were injected with a blue-colored radiopaque medium for microangiography and histology or a diluted methyl methacrylate (MERCOX CL-2B) for scanning electron microscopy.

The distended segments had shortened villi that were separated by expanded crypts and mesothelial cell loss, neutrophil infiltration and edema in the seromuscular layer. The number of filled vessels was decreased in the seromuscular layer and to a lesser extent in the mucosal layer in the distended segments compared to controls. Following reperfusion, the morphologic lesions progressed and the number of observed vessels increased in all layers; however the vascular density did not return to the pre distention state.

This study identifies altered intramural vascular patterns in the equine jejunum during luminal distention and reperfusion.