Liraglutide Preserves Intracellular Calcium Handling in Isolated Murine Myocytes Exposed to Oxidative Stress

In ischemic/reperfusion (I/R) injured hearts, severe oxidative stress occurs and is associated with intracellular calcium (Ca(2+)) overload. Glucagon-Like Peptide-1 (GLP-1) analogues have been shown to exert cardioprotection in I/R heart. However, there is little information regarding the effects of GLP-1 analogue on the intracellular Ca(2+) regulation in the presence of oxidative stress. Therefore, we investigated the effects of GLP-1 analogue, (liraglutide, 10 microM) applied before or after hydrogen peroxide (H(2)O(2), 50 microM) treatment on intracellular Ca(2+) regulation in isolated cardiomyocytes. We hypothesized that liraglutide can attenuate intracellular Ca(2+) overload in cardiomyocytes under H(2)O(2)-induced cardiomyocyte injury. Cardiomyocytes were isolated from the hearts of male Wistar rats. Isolated cardiomyocytes were loaded with Fura-2/AM and fluorescence intensity was recorded. Intracellular Ca(2+) transient decay rate, intracellular Ca(2+) transient amplitude and intracellular diastolic Ca(2+) levels were recorded before and after treatment with liraglutide. In H(2)O(2) induced severe oxidative stressed cardiomyocytes (which mimic cardiac I/R) injury, liraglutide given prior to or after H(2)O(2) administration effectively increased both intracellular Ca(2+) transient amplitude and intracellular Ca(2+) transient decay rate, without altering the intracellular diastolic Ca(2+) level. Liraglutide attenuated intracellular Ca(2+) overload in H(2)O(2)-induced cardiomyocyte injury and may be responsible for cardioprotection during cardiac I/R injury by preserving physiological levels of calcium handling during the systolic and diastolic phases of myocyte activation.