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.
Conclusion: 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.