CHANGES IN PROTEOLYTIC RATE OF DIFFERENT KINDS OF SKELETAL MUSCLE FOLLOWING BURN INJURY AND ITS RELATIONSHIP WITH GLUCOCORTICOID / 解放军医学杂志

ABSTRACT

To observe the changes in proteolytic rate of different kinds of skeletal muscle and the content of serum glucocorticoid in rats after burn injury,to compare the response of different types of skeletal muscle to burn injury,and to preliminarily investigate the factors modulating skeletal muscle proteolysis after burn injury, Wistar rats were inflicted 30%TBSA(total body surface area) full-thickness burn. The rats were randomly divided into 4 groups as the following: 2h, 6h, 12h and 24h after burn injury, each time point was matched with a sham control group. In-vitro muscle incubation system with sufficient oxygen supply as well as amino acid automatic analyzer were used for the assessment of the proteolytic rate of extensor digitorium longus(EDL) and soleus(SOL)muscles. The level of serum glucocorticoid was determined with radio-immuno assay. The result indicated that total proteolytic rate and myofibrillar proteolytic rate in EDL muscle increased strikingly at each time point after burn injury, and the rise of myofibrillar proteolytic rate was even greater in magnitude. No statistically significant difference in total and myofibrillar proteolytic rate occurred in SOL muscle during postburn period. Serum glucocorticoid notably increased in each observation time point compared with that of normal control( P