RESUMO
Objective To investigate the mechanism of changes in skeletal muscle proteolytic rate after escharectomy during early stage of severe burn in rats. Methods One hundred and fifty six Wistar rats were subjected to 30% total body surface area (TBSA) full thickness burn on the back, and they were randomly divided into normal control group (group C), burn injury group (group B), escharectomy during early stage (1 PBD) group (group S)and escharectomy after early stage (4 PBD) group (group N). The extensor digitorium longus (EDL) muscle was collected from each rats using a technique that injury to the muscle was avoided, and the proteolytic rate of EDL was determined after in vitro muscle incubation with sufficient oxygen supply with amino acid automatic analyzer. Transcriptional expression of ubiquitin was assessed by Northern Blot. Results The myofibrillar proteolytic rate (MPR) was markedly increased at each time points after scald, and the MPR in group S was significantly decreased compared with group N. The expression of ubiquitin mRNA markedly increased in the three groups compared with group C, and was decreased in Group S. There was a significant positive correlation between MPR and expression of ubiquitin mRNA. Conclusion Escharectomy during early stage can alleviate protein catabolism in skeletal muscle, and may be related to decreased activity of ubiquitin proteasome pathway