[An experimental study on large fragment deletion of rat myocardial mitochondrial DNA during early postburn stage].
OBJECTIVE
To investigate the influence of peroxidative injury in rat myocardium on the mitochondrial DNA (mtDNA) during early postburn stage.


METHODS
Thirty-six Sprague-Dawley (SD) rats were employed in the study and were randomly divided into sham scald (SS) and scald groups. The rats in scald groups were inflicted with 30% TBSA III degree scalding and were further divided into 1, 3, 6, 12 and 24 post-scald hour (PSH) groups. The mtDNA deletion was determined by semi-quantitative PCR. The rat myocardial tissue samples were harvested and homogenized and the contents of superoxide dismutase (SOD) and malondialdehyde (MDA) were determined.


RESULTS
There was no mtDNA deletion in the rat myocardium in SS group. Partial or complete large fragment (4.8 kb) mtDNA deletion in the rat myocardium was identified at 1, 3 and 24 PSHs (P < 0.05 or 0.01). The SOD activity in the rat myocardium significantly decreased at 1 PSH, reaching the lowest level (76.90 +/- 8.30 U/mg) at 6 PSH, but the MDA content increased evidently at 1 PSH, peaking [(3.17 +/- 0.80) nmol/mg] at 6 PSH (P < 0.05).


CONCLUSIONS
Peroxidative injury to the rat myocardium during early postburn stage might be the principal cause of the 4834 bp deletion of mtDNA in rat myocardium.
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 400038, P.R. China.
Huang
Yue-sheng
YS
Zhao
Song-tao
ST
Li
Xiao-dong
XD
D000818:Animals; D002056:Burns / Q000235:genetics / Q000378:metabolism*; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008929:Mitochondria, Heart / Q000235:genetics* / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors
D004272:DNA, Mitochondrial; D008315:Malondialdehyde; D013482:Superoxide Dismutase