OBJECTIVESTo observe the changes in proteolytic rate and the influence of escharectomy and skin-grafting during shock stage on the proteolytic rate of skeletal muscle in severely scalded rats, and to investigate necessity of escharectomy during shock stage.

METHODSWistar rats afflicted with 30%TBSA (total body surface area) full-thickness burn on the back were randomly divided into 3 groups: burn injury group (group B), escharectomy during shock stage group (group S), and escharectomy after shock stage group (group N). Escharectomy and skin-grafting was performed on the postburn day 1 (PBD1) and PBD4 in group S and N. The extensor digitorium longus (EDL) muscle was collected using a technique without injury to the muscle, and the proteolytic rate of the EDL was determined by the in-vitro muscle incubation system with sufficient oxygen supply and amino acid automatic analyzer.

RESULTSThe total proteolytic rate (TPR) in rat EDL muscles increased significantly (t > 2.988, P < 0.01) on PBD1, but no prominent changes were observed at other time points. There were no statistically significant changes in TPR between group S and group N, but the myofibrillar proteolytic rate (MPR) in rat EDL muscles increased markedly at each time point after scald (t > 2.988, P < 0.01). The MPR in group S decreased significantly as compared with that in group N on PBD2, 4, 5 (t = 2.311, P < 0.05; t = 3.054, 3.319, P < 0.01), and the mean values were 3.17, 2.33, 1.75 nmol/wet weight in g/3 h, respectively. No significant changes were observed between group N and S.

CONCLUSIONThe high protein catabolism of skeletal muscle can be alleviated by escharectomy and skin-grafting during shock stage, and it is beneficial to organics.