Mechanisms of cardioprotective effects of high concentration of magnesium on hypoxia/reoxygenation injury in chronic magnesium deficient rat heart are differ from normal rat heart (LB665)

Magnesium (Mg) deficiency has been reported to be associated with the development of cardiovascular diseases. We have reported that high concentration (12 mM) of extracellular Mg during hypoxia (high-Mg) protected the heart from hypoxia/reoxygenation (H/R) injury, and its protective effect was induced not only by suppression of energy consumption, but also by opening of mitochondrial KATP channel in cardiomyocytes. The aim of this study was to determine whether high-Mg could protect the H/R injury in chronic Mg-deficient (Mg-def) rat heart. Rats were fed an Mg-def diet for 8 weeks, and the hearts were subjected to Langendorff perfusion with the protocol of 30 min hypoxia followed by 30 min reoxygenation. In Mg-def group, the recovery of cardiac function (pressure-rate product; PRP) from H/R injury was significantly impaired than that of control group. Recovery of PRP in Mg-def group was restored to that of control group when extracellular Mg concentration was increased from 1.2 to 12 mM during hypoxia. A ...