Spin trapping evidence for radical generation by isolated hearts and cultured heart cells

The spin trap 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) has been applied to monitor the generation of free oxy-radicals in samples derived from isolated hearts and heart cells. .OH was trapped in the effluent of isolated hearts in the early phase of reperfusion following an ischemia time of only 10 min. Radical detection was possible even when the cardioactive DMPO was added to the effluent after draining off the heart, demonstrating that the short-lived .OH was generated by components released from the affected heart. These results support the hypothesis that radicals are of relevance for reperfusion injury. By omitting antioxidants commonly used for incubation media of cultured cells, it was possible for the first time to demonstrate the formation of .OH in the incubation solution of cardiac cells.