The effects of inhaled nitric oxide on cardiac pathology and energy metabolism in a canine model of smoke inhalation injury

Objective: The effects of inhaled nitric oxide (NO) on cardiac pathology and energy metabolism were studied in a canine model of smoke inhalation injury. Material and method: Twenty-one dogs were randomly divided into three groups: four dogs constituted the normal control group (group N), eight dogs subjected to smoke inhalation followed by O2 inhalation (FiO2=0.45) constituted the injury control group (group C), and nine dogs inhaling a mixture of O2 and 45 ppm nitric oxide after smoke exposure served as the treatment group (group T). Myocardial zymograms were continuously measured, and ventricular muscles were examined for histopathology in the end of the experiment. Results: Lactate dehydrogenase (LDH), alpha-hydroxybutyrate dehydrogenase (alpha-HBD), creatine kinase (CK) and glutamic oxalacetic transaminase (GOT) in group T were less than those in group C(P<0.05, or P<0.01). ATP content and energy charge (EC) in group T were higher significantly than those in group C(P<0.01). Light microscopy and electron microscopy indicated that the ventricular pathologic changes in group T were milder than in control group. Conclusion: Nitric oxide inhalation relieved myocardial damage and improved energy metabolism.