| The metabolic rate will increase after major burns, because excitability of sympathetic nervous system will be reinforced and the amount of infective medium will be raised, which may be resulted from some stimulating factors such as destruction of skin barrier, shock, infection, burned eschar toxins, etc. Hypermetabolism will do harm to the burned patients and many complications will be easy to occur if it lasted for long time. To suppress the intensity as well as shortening the course of hypermetabolism is an important aspect of the treatment. Uncoupling proteins (UCPs), located in the inner membran of mitochondria, express in some tissues, for instance, skeletal muscle, liver and white adipose tissue, which have certain influences on the yield and storage of energy. UCPs could uncouple oxidation of substrate and phosphorylation of ADP, so that the energy released from oxidation of carbohydrate and lipid will not be stored in the energy-rich phosphate bond, but distributed as heat. It accounts for a certain protortion in BMR.A specific medicine, which could regulate metabolic rate to a appropriate level, has not been found until now. For the burned patients, although the pathophysiological alterations are complicated, the presence of eschar is undoubtedly one of the key factors inducing the pathological process and alteration of metabolic rate. To conduct escharectomy and cover the wounds actively, try to shorten the progress are the main measures of treatments. At the same time, it could reduce metabolic rate effectively.OBJECTIVEEscharectomy during shock stage has shown pretty good effects in terms of improving medical treatment level as well as suppressing hypermetabolism. In previous studies, it could be found that metabolic rate declined markedly in those patients or animals who received escharectomy during shock stage. It could be classified that existences of necrotic tissues and wounds not only impact survival rate of the patients, but also are key factors inducing hypermetabolism. Along with the progresses of scientific research means, it's necessary to explore the mechanisms of hypermetabolism postburns and the suppressive effects of escharectomy in molecular level. In the present study, some hormones, cytokines, which are related to hypermetabolsim, and UCPs expression in skeletal muscle, liver and white adipose tissue are investigated inthe 30% third degree scalded rats. In order to further demonstrate the necessity of conducting escharectomy during shock stage, the effects of eschar extraction on expression of UCPs in skeletal muscle cells in vitro were also explored. The objective of the present study are as follows:1. To observe the effects of burn injuries and escharectomy at different time on the level of several hormones, cytokines, leptin and free fatty acid in plasma.2. To observe the effects of burn injuries and escharectomy at different time on expression of UCP2mRNA, UCP3mRNA in skeletal muscle, liver and adipose tissue, as well as energy metabolism in skeletal muscle and liver.3. To culture skeletal muscle cells in vitro and make eschar extraction of scalded rats skin. To observe the effects of eschar extraction on expression of UCPs in skeletal muscles in vitro.METHODS1. Animal: 30% TBSA full thickness scalded rats were employed and divided into four groups. Rats in group A (scalded control) were killed at 8, 24, 96, 120, 168h respectively after burns; rats in group B (escharectomy at 8h after burns) were killed at 24, 96, 120, 168h after burns; rats in group C (escharectomy at 24h after burns) were killed at 96, 120, 168h after burns; rats in group D (escharectomy at 96h after burns) were killed at 120, 168h after burns. There are eight rats in each time point, and eight rats which were not scalded were signed as normal control. Rats in group B, C, D received escharectomy at 8,24,96h respectively. Serum, skeletal muscle, liver, epididymidis fat pad were collected when the rats were killed.2. The parameters analyzed are as follows:...
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