[A scanning electron microscopic study on experimental ischemic lesions in dogs]

Occlusion of minute vessels in the bowel wall is thought to be a cause of ischemic lesions. This study was performed to clarify the pathohistology and the morphology of these various lesions. Microbarium suspension was injected into the mesenteric vessels of twenty four dogs and the ischemic lesions were produced experimentally. The degree of the bowel damage was parallel to the amount of injected microbarium suspension. The resected specimen of the various stages of the disease was studied histologically and morphologically by a scanning electron microscopy. With the small amount of barium suspension the lesions were confined to the mucosal layers. The epithelial cells regenerated regularly and the villi normalized rather quickly, and these lesions healed within one to two weeks (transient form). With the large amount of barium suspension the lesions involved both submucosal and muscular layers. The epithelial cells regenerated irregularly and the villi rearranged to abnormal forms. These lesions healed in two to four weeks leaving the stenosis due to scar formation (stricturing form). This study suggests that scanning electron microscopic investigation can be used to assess the details of morphological changes of ischemic mucosa, special reference to the degeneration and regeneration process of epithelium of the villi.