The experimental studies on stress ulcer of the stomach following thermal injury with special reference to H⁺ back diffusion and microcirculation

Summary

We have investigated the relationship of H⁺ back diffusion and the fine microvascular structure of arteriovenous (A-V) shunting channels to the formation of gastric mucosal lesions following thermal injury. Rats subjected to a third degree burn of 30% of the body surface were investgated at times varying from immediately after the burn to 72 hours post burn and compared to sham burned controls. The protein leakage into the lumen was also determined in order to evaluate the capillary permeability of the gastric mucosa. The incidence of mucosal lesions was the highest in the animals studied in the first few hours after burn injury. Whereas none of the controls had any evidence of mucosal lesions. 93% of animals studied at 2 hours post burn and 100% of animals studied at 5 hours post burn had mucosal lesions. Both the incidence and severity of mucosal lesions were less in the animals studied at 24 and 72 hours, suggesting that the lesions that were evident at the later times were probably formed during the first few hours and not yet healed histopathologically. At 2 and 5 hours, H⁺ back diffusion and protein leakage were increased significantly above the control value and microangiographical studies revealed the opening of A-V shunting channels. At 24 and 72 hours there was no significant opening of A-V shunting channels and H⁺ back diffusion was within the control value.

Thus it appeared that increased H⁺ back diffusion and the opening of A-V shunting channels might have been intimately related to the formation of mucosal lesions during the first few hours after the burn injury.