Effects of High Glucose on Simulated Ischemia/Reperfusion Injury in Isolated Cardiomyocytes

The rising prevalence of type 2 diabetes is linked to an increased risk of cardiovascular diseases, with the diabetic heart being particularly vulnerable to ischemia-reperfusion (IR) injury. Chronic hyperglycemia contributes to an increase in reactive oxygen species and impacts the homeostasis of biochemical pathways, including the polyol pathway, increasing susceptibility to damage. Aldose reductase (AR), a key enzyme in this pathway, has been targeted for therapeutic intervention, with AR inhibitors showing potential in mitigating diabetic complications. This study investigated IR injury in cardiomyocytes following high glucose exposure and assessed the AR inhibitor Epalrestat as a protective agent. Cardiomyocyte function was evaluated by measuring lactate dehydrogenase (LDH) release, FM1-43 membrane incorporation, cell viability, intracellular calcium accumulation, and superoxide anion formation. High glucose exposure and simulated IR led to increased LDH release, FM1-43 incorporation, intracellular calcium, and superoxide levels, alongside reduced cell viability in a dose-dependent manner. However, Epalrestat treatment during high glucose exposure significantly reduced IR-induced injury. These findings suggest that high glucose exacerbates IR injury in cardiomyocytes, with the polyol pathway playing a critical role. Targeting this pathway with AR inhibitors like Epalrestat may offer a protective strategy against diabetic heart complications.