[The isolation and purification of 19S regulator compound and the change of its protein level in rat skeletal muscle after severe scalding].

Objective: To explore the role of 19S regulator compound protein in the degradation of skeletal muscle protein in scalded rats.

Methods: Wistar rats were scalded and they were randomly divided into normal and 1, 2, 3, 5, and 7 postburn day (PBD) groups with 8 rats in each group. The 19S regulator compound of skeletal muscle in scalded rats was isolated and purified with chromatography. Rabbit-anti-rat antibody IgG of 19S regulator compound was prepared conventionally. The antibody was injected to rats in injection group (I) in which 19S antibody in dose of 3 mg/kg BW was injected for two times via tail vein with 6-hour interval. The rats in I group were decapitated on 1, 2 and 3 post-injection days, respectively. The scalded rats in control group (C) were treated in the same way, except that the antibody was replaced by normal saline. The change in content of 19S regulator compound was determined by western-blot. Meanwhile, the releasing rate of tyrosine from the skeletal muscle of scalded rats was also detected by fluorescent photography.

Results: 19S regulator compound with high purity was obtained. The content of 19S regulator compound in rat skeletal muscle was increased significantly after 2 PBD. But the protein degradation rate was also obviously increased on 2 PBD. The antibody of 19S compound might inhibit the enhancement of protein degradation.

Conclusion: Burn injury might up-regulate the protein level of skeletal muscle 19S regulator compound, which therefore activated the protein degradation by 26S protease compound. This might be an important factor leading to postburn negative nitrogen balance.