[Study on the mechanism of alleviation of myocardial injury after early escharectomy en masse of several burns in rat].
OBJECTIVE
To investigate the alleviation of myocardial injury of rats after early escharectomy en masse of severe burns, and to explore its molecular mechanism.


METHODS
Totally 66 SD rats were randomly divided into normal control (n=6), non-escharectomy (NE, n=30) and escharectomy (E, n=30, with total escharectomy 20 minutes after burns ) groups. The rats in the NE and E groups were inflicted with 30% TBSA full-thickness scald. The content of ATP in mitochondria, troponin I (Tn I) in serum and 4.8-kb deletion of myocardial mitochondrial DNA (mtDNA) of the rats in each group were determined at 1, 3, 6, 12 and 24 post-scald hours (PSH).


RESULTS
(1) The content of ATP in myocardial mitochondria was decreased in both E and NE groups, but it was obviously increased at 1 and 6 PSH (0.90 +/- 0.27 microg/mg 0.66 +/- 0.19 microg/mg) in E group when compared with those in NE group (0.74 +/- 0.18 microg/mg, 0.46 +/- 0.21 microg/mg, P < 0.05). (2) There was no obvious change in the serum content of Tn I in E group at 1 and 3 PSH, but the respective content in 1, 3 and 6 PSH was markedly lower than those in NE group (P < 0.05). (3) The 4.8 kb deletion of myocardial mtDNA was found at 1, 3, 24 PSH in NE group, while it was observed only at 1, 12 PSH in E group. The partial and whole deletion rate in E group was lower than that in NE group.


CONCLUSIONS
Early escharectomy en masse can significantly alleviate the myocardial injury after burns,which might be related to its effect in lowering the deletion rate of myocardial mtDNA at early postburn stage.
Zhang
Dong-xia
DX
Institute of Burn Research, Southwest Hospital, State Key Laboratory of Trauma, Burns and Combined Injury, The Third Military Medical University, Chongqing, PR China.
Huang
Yue-sheng
YS
Li
Xiao-dong
XD
Dang
Yong-ming
YM
Wang
Pei
P
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002056:Burns / Q000378:metabolism* / Q000601:surgery*; D004272:DNA, Mitochondrial / Q000235:genetics*; D004195:Disease Models, Animal; D005260:Female; D008297:Male; D008929:Mitochondria, Heart / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017384:Sequence Deletion; D019210:Troponin I / Q000097:blood
D004272:DNA, Mitochondrial; D019210:Troponin I; D000255:Adenosine Triphosphate