Cardioprotective effects of ascorbic acid on the injury induced by ischaemia-reperfusion in isolated mammalian heart

The aim of this work was to examine the effect of ascorbic acid on ischaemia-reperfusion changes in the mammalian heart. Isolated Langendorf-perfused rat hearts were subjected to substrate-free global anoxia for 30 min followed by oxygenated reperfusion for another 30 min. The deterioration in heart rate and force of contraction during ischaemia-reperfusion were observed every 5 min. The effects of various concentrations of exogenous vitamin C (5, 50, 500 mu g g(-1)) were investigated under ischaemia-reperfusion conditions. In controls during ischaemia, the heart stopped completely after 10 min from the start of ischaemia. During reperfusion, the heart recovered from asystole but the recovery was only 53 +/- 1.44% of the preischaemic start value. After pre-treatment with vitamin C (50 mu g g(-1)) the heart deteriorated less during ischaemia and recovered more during reperfusion 83.56 +/- 1.5%. Vitamin C 5 mu g g(-1) had no significant effects on ischaemia-reperfusion changes. Vitamin C 500 mu g g(-1) stopped the heart completely after 3 min.