Mild Hypothermia Protects Pigs’ Gastric Mucosa After Cardiopulmonary Resuscitation via Inhibiting Interleukin 6 (IL-6) Production

BACKGROUND The purpose of this study was to determine the effect of mild hypothermia therapy on gastric mucosa after cardiopulmonary resuscitation (CPR) and the underlying mechanism. MATERIAL AND METHODS Ventricular fibrillation was induced in pigs. After CPR, the surviving pigs were divided into mild hypothermia-treated and control groups. The changes in vital signs and hemodynamic parameters were monitored before cardiac arrest and at intervals of 0.5, 1, 2, 4, 6, 12, and 24 h after restoration of spontaneous circulation. Serum IL-6 was determined at the same time, and gastroscopy was performed. The pathologic changes were noted, and the expression of IL-6 was determined by hematoxylin and eosin (HE) staining and immunohistochemistry under light. RESULTS The heart rate, mean arterial blood pressure, and cardiac output in both groups did not differ significantly. The gastric mucosa ulcer index evaluated by gastroscopy 2 h and 24 h after restoration of spontaneous circulation (ROSC) in the mild hypothermic group was lower than that the control group (P<0.05). The inflammatory pathologic score of gastric mucosa in the mild hypothermic group 6-24 h after ROSC was lower than that in the control group (P<0.05). Serum and gastric mucosa IL-6 expression 0.5-4 h and 6, 12, and 24 h after ROSC was lower in the mild hypothermic group than in the control group (P<0.05). CONCLUSIONS Mild hypothermia treatment protects gastric mucosa after ROSC via inhibiting IL-6 production and relieving the inflammatory reaction.