Microvascular Changes in Experimental Gastric Stress Ulceration: The Influence of Allopurinol, Cimetidine, and Misoprostol

The influence of stress on the structure of the gastric mucosal capillary network was investigated in an experimental model using scanning electron microscopy (SEM) to study corrosion casts of the gastric microvasculature. An index of microcirculatory patency was devised to improve the objectivity of SEM. Stress (mean score 42.4 ± 4.7) severely disrupted the structure of the mucosal capillary network when compared with controls (mean 5.0 ± 2.9) ( P < 0.01). Disruption of the microvascular network was significantly reduced by pretreatment with allopurinol, cimetidine, and misoprostol, these groups having mean damage scores of 17.4 ± 5.8, 21.2 ± 7.9, and 28.6 ± 9.3, respectively, when compared with untreated stressed controls in which the mean score was 42.4 ± 4.7 ( P < 0.02). Microvascular disruption is a significant factor in stress ulceration and the efficacy of allopurinol in minimizing the stress-induced disruption of the microvascular network provides further indirect evidence for the role of ischemia and oxygen-derived free radical generation in its etiology.