Glycogen Synthase Kinase 3β Inhibition Protects the Cardiomyocytes from Anoxia/Reoxygenation Injury by Modulating Inflammatory Response and Reducing the Opening of mPTP

Abstract

Background: Phosphorylation of glycogen synthase kinase 3β (GSK-3β) is crucial in multiple cardioprotective signaling pathways. But the downstream mechanism is unclear. Considering GSK-3β is the key regulator of nuclear factor-κB (NF-κB) and mitochondrial permeability transition pore (mPTP) is a critical determinant of lethal reperfusion injury, we assessed the mechanism of postconditioning with the selective inhibitor of GSK-3β associated with modulating in fl ammatory response and reducing the opening of mPTP. Methods: After cultured for 72 hours, neonatal rat cardiomyocytes were randomly divided into 3 groups according to random number table: Sham group, anoxia/reoxygenation injury group (AR group) and GSK-3β inhibitor TDZD -8 postconditioning group (TDZD -8 group). At the end of the experiment, the lactate dehydrogenase (LDH) release rate, myocardial apoptosis and the supernatant concentrations of interleukin (IL)-6 and tumor necrosis factor (TNF)-α were measured. The NF-κBp65 and phosphorylated NF-κBp65Ser536 in all samples were assessed by western-blotting technique. The mitochondrial membrane potential was measured by rhodamine 123 staining flow cytometry and confocal laser scanning microscope. Results: We discovered that postconditioning with GSK-3β inhibitor TDZD -8 could significantly protect against cardiomyocyte anoxia/reoxygenation injury, as shown by reducing the early apoptosis and LDH release rate. And this cardioprotective method could significantly attenuate inflammatory response to the anoxia/reoxygenation injury, as evidenced by decreasing the activity of NF-κB and levels of inflammatory cytokines, such as IL-6 and TNF-α. Furthermore, it could significantly reduce the irreversibly high level opening of the mPTP, as evidenced by increasing the mitochondrial membrane potential of anoxia/reoxygenation cardiomyocyte. Conclusions: Our current results indicated that postconditioning with GSK-3β inhibitor TDZD -8 significantly attenuated the systemic inflammatory and reduced the opening of mPTP response to cardiomyocytes anoxia/reoxygenation injury.