Effects of cimetidine, a histamine type 2 receptor antagonist, on microcirculatory disturbance of the stomach induced by full-thickness burn injuries as a model for surgical stress in rats.

BACKGROUND: We have reported the preventive effect of cimetidine, a histamine type 2 receptor antagonist, on decreased gastric mucosal blood flow induced by burn injury, a model of surgical stress. OBJECTIVE: The present study was performed to assess the effects of cimetidine on gastric microcirculatory disturbance induced by surgical stress. METHODS: Twelve male Wistar rats were anesthetized and a 30% full-thickness dorsal scald burn was inflicted. The total lengths of gastric erosions were measured using stereoscopic microscopy. Microvascular images in the basal region of the gastric mucosa were observed using an intravital microscope, and the diameters of venules and collecting venules were measured. Rolling leukocytes inside and along the venules, an indication of endothelial damage to the microcirculation, were observed. The rats were assigned to the cimetidine group or the control group (both, n = 6). Cimetidine 100 mg/kg was administered 30 minutes before and 2.5 hours after infliction of the burn injury. Animals in the control group were given only isotonic saline. Values are expressed as mean (SD). RESULTS: Contraction of venules was easily observed in all rats in the control group. However, venular contraction was rarely observed in the cimetidine group. The total length of gastric erosions was significantly decreased in the cimetidine group compared with the control group (0.93 [0.58] µm vs 5.98 [5.18] µm, respectively; P < 0.05). The percentages of rolling leukocytes that passed the confluence of a prevenule and a venule were also significantly decreased in the cimetidine group compared with the control group (4.7% [7.3%] vs 22.6% [5.7%]; P < 0.01). The diameters of the venules and collecting venules were significantly larger in the cimetidine group (57.3 [6.8] µm and 75.9 [3.6] µm, respectively) than in the control group (30.9 [9.2] µm and 46.8 [8.0] µm, respectively) (both, P < 0.01). CONCLUSIONS: The present study suggests that cimetidine may have a protective effect against gastric microcirculatory disturbances induced by burn injury, a model of surgical stress.