Protection by coenzyme Q10 of canine myocardial reperfusion injury after preservation.

This study was undertaken to assess whether pretreatment of the donor heart with coenzyme Q10 could improve postischemic myocardial recovery. Coenzyme Q10 or its solvent was administered intravenously to donor dogs 1 hour before isolation of the heart. Each heart was stored in Euro-Collins solution at 4 degrees C for 6 or 24 hours and then was reperfused via the aorta with arterial blood of a supporting dog for 3 hours at 37 degrees C in a working mode. During preservation, adenosine triphosphate level was significantly reduced in the placebo group from 21.0 mumol/gm dry weight to 15.1 and 11.9 after 6 and 24 hours of preservation, respectively. Coenzyme Q10 pretreatment maintained the adenosine triphosphate level at 18.9 even after 24 hours of preservation. After reperfusion following 6 and 24 hours of preservation, the adenosine triphosphate level recovered to the original level in the coenzyme Q10 group, but it remained significantly low in the placebo group. Preservation and subsequent reperfusion caused a significant increase in the level of malondialdehyde of hearts in the placebo group, and coenzyme Q10 pretreatment completely suppressed the increase in the malondialdehyde level after reperfusion. Ventricular functions were improved in the coenzyme Q10 group. These results support the concept that free radicals play an important role in myocardial injury during preservation and subsequent reperfusion and suggest that pretreatment of the heart with coenzyme Q10 is effective in preventing such injury that may develop after reperfusion.