[Gene expression of C2 subunit of proteasome in cardiac muscle in burned rats with sepsis].
OBJECTIVE
To study the gene expression of C2 subunit of proteasome and proteolysis in cardiac muscle in burned animals with sepsis.


METHODS
Male Wistar rats were randomly divided into burn group, burn sepsis group and control group. The extent of burn injury was 30% total body surface area (TBSA) III degree burn, and the model of burn sepsis was replicated by administration of endotoxin (6 mg/kg) into the peritoneal cavity immediately after burn injury. The contents of 3-methylhistidine (3-MH) in cardiac muscle were determined with high performance liquid chromatography. The expression of C2 subunit mRNA in the cardiac muscle was assessed with Northern blot analysis.


RESULTS
The contents of 3-MH in cardiac muscle of burned rats with sepsis increased significantly at 2 hours and 6 hours, as compared with burned rats and normal control (all P<0.01). There was no marked difference of contents of 3-MH in cardiac muscle between burned rats at 2 hours and control group, however, the contents of 3-MH in cardiac muscle of burned rats at 6 hours increased significantly compared with control group. The gene expression of C2 subunit in cardiac muscle of burned rats with sepsis increased significantly at 2 hours and 6 hours compared with burned rats and normal control (all P<0.01). There were significant differences in the intensity of gene expression of C2 subunit in cardiac muscle between burned rats at 2 hours and 6 hours and normal control (all P<0.01).


CONCLUSIONS
The data suggest that the activity of ubiquitin system, one of important protein degradation pathways, and the proteolysis in cardiac muscle is continuously enhanced after burn injury, especially when sepsis set in, probably contributes to abnormal protein metabolism with malfunction of the heart during burn sepsis.
Shen
Chuan-an
CA
Burns Institute, 304th Clinical Department of General Hospital of PLA, Beijing 100037, China.
Chai
Jia-ke
JK
Yao
Yong-ming
YM
Sheng
Zhi-yong
ZY
Jiang
Jin-heng
JH
D000818:Animals; D002056:Burns / Q000150:complications / Q000378:metabolism*; D004195:Disease Models, Animal; D008297:Male; D008762:Methylhistidines / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D018805:Sepsis / Q000209:etiology / Q000378:metabolism*
D008762:Methylhistidines; D012333:RNA, Messenger; D046988:Proteasome Endopeptidase Complex; C028118:3-methylhistidine