Microvascular changes of gastric mucosa in the development of stress ulcer in rats A scanning electron microscopic study of vascular casts

Under a scanning electron microscope, the microcirculation in the stomachs of rats under stress was observed by a corrosion casting technique. Stress ulcers were induced by a cold immersion and restraint method. After a short time of stress, the vascular pattern showed serpentining and narrowing of the capillaries and a local depression of the capillary network. After a moderately long time, defects in the vascular network began to appear and outflowings of Mercox from the venule became prominant. Casts of interrupted collecting venules were frequently seen. With further increase in the time of stress, the interruptions in the cast of the capillaries and collecting venules which were dilated, increased. These vessel changes descended deeper and deeper into the mucosa vessels but were limited to the laminapropria and did not extend to the muscularis mucosae. After stress following truncal vagotomy, the vasculature showed serpenting and narrowing of the capillaries. But there were few defects in the capillaries and capillary network. In the case released from a short time of stress, Y-shaped duplicated vessels were often observed on the defective capillaries. In the case released from prolonged stress, newborn buds were seen on the defective capillaries and collecting vessels. Duplicated capillaries and collecting vessels ran toward the surface of the mucosa.