Apoptotic Cell Death in Cardiomyocytes Induced by Hypoxia from Cobalt Chloride Is Hastened by SGLT-1 Inhibition

Abstract

Introduction: Myocardial ischemia is responsible for the deaths of millions of people every year. Cardiac hypoxia reduces the efficiency with which the heart muscle pumps blood. When one or more of the coronary arteries abruptly and severely narrows or closes off, this is known as an acute coronary syndrome (ACS). Ischemia of the heart muscle can also cause potentially fatal arrhythmias. More information about this topic is required. Methods: The effects of SGLT-1 inhibition were studied using a different disease model, the cobalt chloride (CoCl2) hypoxia paradigm. The MTT assay was used to examine the effects of CoCl2 with and without Phlorizin (PZ) on glucose uptake, caspase activity, and metabolic/cytotoxic activities in SGLT-1 overexpressed H9C2 cells. Both SGLT-1 siRNA silencing and PZ treatment of SGLT-1 overexpressed neonatal rat cardiomyocytes were studied. Results and Discussion: Using flow cytometry, we were able to distinguish between metabolically active (PI-stained) and inactive (annexin-stained) live cells, as well as apoptotic (annexin-stained) and necrotic (PI-stained) cells. Caspase 3, 9, bcl-2, HIF-1a, and SGLT-1 expression, as well as oxidative stress, were examined using Western blotting. H9C2 cells showed increased caspase 3 and 9 activity in the CoCl2 group compared to the control, and these increases were further amplified by PZ cotreatment. PZ did not counteract CoCl2's effects of decreased glucose absorption and MTT activity. Conclusion: PZ increased cardiomyocyte apoptosis and decreased metabolic quiescent cells. PZ had no effect on the oxidative stress and necrosis that CoCl2 caused. CoCl2-induced SGLT-1 reduction leads to rapid apoptotic cell death.