Sarita Nehra1, Varun Bhardwaj, Deepika Saraswat. 1. *Defence Research and Development Organization, New Delhi, India; and †Department of Experimental Biology, Defence Institute of Physiology and Allied Science.
Abstract
BACKGROUND: Hypoxia-induced rise in intracellular calcium concentration is a causative agent of apoptosis and oxidative damage in cardiomyocytes. We examined the efficacy of calcium channel blocker amlodipine in preventing hypoxia-induced apoptosis in H9c2 cells and restoring oxidative balance. METHODS: H9c2 cells were exposed to hypoxia (0.5% oxygen) to evaluate the efficacy of amlodipine in restoring cellular calcium levels. Cellular markers of apoptosis (Bax/Bcl2 and caspase-3, -7, and -9) and pro-survival markers (Akt/p-Akt levels) were evaluated under hypoxia. Redox damage was evaluated by assessing markers of oxidative damage, that is, glutathione reduced, glutathione oxidized, lipid peroxidation, reactive oxygen species, and manganese superoxide dismutase activity. Cellular adenosine triphosphate (ATP) pool and AMPKα levels were measured to evaluate regulation of metabolism under hypoxia. RESULTS: Amlodipine treatment at 25 nM prevented apoptosis and restored cellular calcium levels and oxidative damage in cardiomyocytes. Stabilization of caspase-3, -7, and -9 along with restoration of Akt/p-Akt levels depicted pro-survival efficacy of amlodipine. Also, restoration of cellular ATP and AMPKα levels indicates that amlodipine prevents cardiomyocytes from hypoxia-induced metabolic stress. CONCLUSIONS: Amlodipine thus protects H9c2 cells from hypoxia-induced apoptosis by regulating Akt/p-Akt-mediated caspase-3, -7, and -9 activation and restoring cellular ATP and redox status.
BACKGROUND:Hypoxia-induced rise in intracellular calcium concentration is a causative agent of apoptosis and oxidative damage in cardiomyocytes. We examined the efficacy of calcium channel blocker amlodipine in preventing hypoxia-induced apoptosis in H9c2 cells and restoring oxidative balance. METHODS: H9c2 cells were exposed to hypoxia (0.5% oxygen) to evaluate the efficacy of amlodipine in restoring cellular calcium levels. Cellular markers of apoptosis (Bax/Bcl2 and caspase-3, -7, and -9) and pro-survival markers (Akt/p-Akt levels) were evaluated under hypoxia. Redox damage was evaluated by assessing markers of oxidative damage, that is, glutathione reduced, glutathione oxidized, lipid peroxidation, reactive oxygen species, and manganese superoxide dismutase activity. Cellular adenosine triphosphate (ATP) pool and AMPKα levels were measured to evaluate regulation of metabolism under hypoxia. RESULTS:Amlodipine treatment at 25 nM prevented apoptosis and restored cellular calcium levels and oxidative damage in cardiomyocytes. Stabilization of caspase-3, -7, and -9 along with restoration of Akt/p-Akt levels depicted pro-survival efficacy of amlodipine. Also, restoration of cellular ATP and AMPKα levels indicates that amlodipine prevents cardiomyocytes from hypoxia-induced metabolic stress. CONCLUSIONS:Amlodipine thus protects H9c2 cells from hypoxia-induced apoptosis by regulating Akt/p-Akt-mediated caspase-3, -7, and -9 activation and restoring cellular ATP and redox status.