Z Wang1, B Cai, W Zhou. 1. Department of Burns and Plastic Surgery, 205th Hospital of People's Liberation Army, Jinzhou 121001.
Abstract
OBJECTIVE: The electron transport chain alterations of myocardial mitochondria and cardiac dysfunction were studied after severe burn injury. METHODS: Contraction properties of male Sprague-Dawley rat cardiac muscle were investigated at 2, 4, 6 hours after 30% TBSA full-thickness thermal injury. Meanwhile, changes in electron transport chains of myocardial mitochondria were measured. Mitochondria were obtained by differential centrifugation. Succinate-respiratory chains and NADH-respiratory chains were assayed polarographically and spectrophotometrically in isolated myocardial mitochondria respectively. RESULTS: The results showed that thermal injury led to decrease in the activities of two respiratory chains. At 2 h postburn, the activities of NADH-cytochrome C reductase and cytochrome oxidase declined significantly as compared with that of the sham-operated group, and at 4 h postburn, all activities of succinate-Co. Q reductase, succinate-cytochrome C reductase, NADH-Co. Q reductase were much lower than those of the sham-operated group. Along with the electron transport chain alterations of myocardial mitochondria, there were decrease in myocardial contractile function in burned rats. CONCLUSION: These results imply that weakness of myocardial contractile function resulting in the decrease in cardiac output may be associated with the impairment of utilization of oxygen in myocardial mitochondria following burn injury.
OBJECTIVE: The electron transport chain alterations of myocardial mitochondria and cardiac dysfunction were studied after severe burn injury. METHODS: Contraction properties of male Sprague-Dawley rat cardiac muscle were investigated at 2, 4, 6 hours after 30% TBSA full-thickness thermal injury. Meanwhile, changes in electron transport chains of myocardial mitochondria were measured. Mitochondria were obtained by differential centrifugation. Succinate-respiratory chains and NADH-respiratory chains were assayed polarographically and spectrophotometrically in isolated myocardial mitochondria respectively. RESULTS: The results showed that thermal injury led to decrease in the activities of two respiratory chains. At 2 h postburn, the activities of NADH-cytochrome C reductase and cytochrome oxidase declined significantly as compared with that of the sham-operated group, and at 4 h postburn, all activities of succinate-Co. Q reductase, succinate-cytochrome C reductase, NADH-Co. Q reductase were much lower than those of the sham-operated group. Along with the electron transport chain alterations of myocardial mitochondria, there were decrease in myocardial contractile function in burned rats. CONCLUSION: These results imply that weakness of myocardial contractile function resulting in the decrease in cardiac output may be associated with the impairment of utilization of oxygen in myocardial mitochondria following burn injury.