Iron-load increases the susceptibility of rat hearts to oxygen reperfusion damage. Protection by the antioxidant (+)-cyanidanol-3 and deferoxamine.

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Abstract
To investigate whether iron is involved in the reperfusion syndrome by aggravating free radical injury, the hearts from iron-loaded and control rats were perfused under normoxic, anoxic, and reperfusion conditions. Normoxic perfusion revealed no change in coronary flow, contractility, or lactate dehydrogenase (LDH) release between these two groups. Under anoxic and reperfusion conditions, however, we found a significant increase of ventricle fibrillation (56% vs. 0%, p less than 0.01, n = 9), a significantly lower recovery of contractility (21 +/- 7.4% vs. 81 +/- 6.6%, mean +/- SEM; p less than 0.001), and a significant increase of LDH release (667 +/- 142 vs. 268 +/- 37 mU LDH/min/g wet wt, mean +/- SEM; p less than 0.05). Administration of either 20 microM of the antioxidant (+)-cyanidanol-3 or 50 microM of the iron-chelator deferoxamine totally prevented the generation of ventricle fibrillation and normalized contractility to control levels in the iron-loaded group. Moreover, 20 microM (+)-cyanidanol-3 significantly lowered LDH release in this period (312 +/- 67 mU), whereas deferoxamine had no protective effect on this LDH release (1,494 +/- 288 mU). Normal hearts appeared to be protected by 20 microM (+)-cyanidanol-3 as well. In this group (n = 6), a significantly higher recovery of contractility (97.1 +/- 3.2% vs. 81 +/- 6.6%, p less than 0.05) and a significantly lower release of LDH (110 +/- 27 vs. 268 +/- 37 mU, p less than 0.05) was found compared with the control group (n = 9). No difference in superoxide dismutase or glutathione peroxidase activity was found between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)