RESUMEN
<p><b>OBJECTIVE</b>To investigate the influence of pinacidil preconditioning on the protection of the structure and respiratory function of injured myocardial mitochondria in scalded rats.</p><p><b>METHODS</b>Seventy-five healthy Wistar rats, weighed 250 approximately 300 g, were randomly divided into three groups: i.e. control (n = 9, with intraperitoneal injection of 50 microg/kg isotonic saline), scald (n = 33, with 30% TBSA full thickness scald) and pre-conditioning (n = 33, with same extent of scald injury after intraperitoneal injection of 50 microg/kg pinacidil) groups. Mitochondrial ultrastructure was observed by transmission electron microscope. The mitochondrial respiratory function, the MDA content and the superoxide anion level were determined with corresponding methods.</p><p><b>RESULTS</b>The degree of injury to rat myocardial mitochondria in pre-conditioning group was less intensive than that in scald group (P < 0.05 or 0.01). The respiratory control rate in pre-conditioning group was obviously higher than that in scald group (P < 0.05), and the contents of MDA and superoxide anion in pre-conditioning group were markedly lower than those in scald group (P < 0.05 or 0.01), as evidenced by their contents at 3 post scalding hours (0.60 +/- 0.09 micromol/g and 0.127 +/- 0.020) were obviously lower than those in scald group (0.83 +/- 0.07 micromol/g and 0.169 +/- 0.015) (P < 0.01).</p><p><b>CONCLUSION</b>Pinacidil preconditioning was beneficial in the protection of myocardial mitochondria in scalded rats, and it might be related to the pre-opening of potassium channel which was sensitive to mitochondrial ATP.</p>