Changes in myocardial mitochondrial Ca2＋ concentration and its mechanism in the early stage of severe burn

AIM:To investigate the change in myocardial mitochondrial Ca^2＋ concentration ( Ca²⁺]_m) and its mechanism in the early stage of severe burn. METHODS:An experimental model of 30%TBSA full-thickness skin scalding was reproduced in rats. Ca²⁺]_m, cytosolic Ca^2＋ concentration ( _c) and mitochondrial Ca^2＋ transport velocity were determined. RESULTS: ① Ca²⁺]_m increased evidently at 1st hour postburn, and continuously at 3rd hour, reached the peak at 6th hour postburn, then, it decreased at 12th and 24th hour, but remained in higher level than that of the control. ② There was no significant difference in _c between 1st hour postburn and the control, but _c increased evidently at 3rd, 6th, 12th, 24th hour postburn. ③ mitochondrial Ca^2＋ uptake velocity at 1st hour postburn was higher than that of control, and Ca^2＋ release velocity didn't change obviously, but both of them were decreased at 3rd, 6th, 12th, 24th hour postburn. ④ Ca²⁺]_m was positive correlated with _c after burn, and negative correlated with mitochondrial Ca^2＋ release velocity at 3rd, 6th, 12th, 24th hour postburn, respectively. CONCLUSION: There was obvious Ca^2＋ overload in myocardial mitochondria after severe burn, the mechanism of which might include ascent of _c and disorder of Ca^2＋ transport in mitochondria.