Mitochondria as Targets for Nitric Oxide–Induced Protection During Simulated Ischemia and Reoxygenation in Isolated Neonatal Cardiomyocytes

• DOI: 10.1161/01.cir.103.21.2617
• Publication Date: 2012-06-12T00:09:32Z
• Authors: Roby D. Rakhit; Mart H. Mojet; Michael S. Marber; Michael R. Duchen
• Keywords: Snap; Propidium iodide

Background —As shown previously, exposure to NO donors initiates protective mechanisms in cardiomyocytes that persist after removal of the donor, a form pharmacological preconditioning. Because also affects mitochondrial respiration, we studied effect on Ca 2+ uptake. Methods and Results —Neonatal rat ventricular myocytes primary culture were exposed 1 hour simulated ischemia reoxygenation (sI/R). Pretreatment with donor S -nitroso- N -acetyl-penicillamine (SNAP) (1 mmol/L for 90 minutes), followed by washing incubation 10 30 minutes, reduced sI/R-induced cell death 25.4% compared control (propidium iodide exclusion assay, P <0.001). Short (10-second) exposures SNAP reversibly suppressed respiration without detectable change potential. In contrast, treatment minutes caused modest but sustained depolarization, as judged JC-1 fluorescence. pretreatment limited cellular overload during (fura-2 ratio rose 226±40% versus 516±170% baseline, n=5, <0.05) prevented loss membrane integrity reoxygenation. significantly ability mitochondria accumulate face similar cytosolic load (peak rhod-2 fluorescence 133±4% 166±7% baseline at fluo-3 levels, =0.0004, n=52 25, respectively). Conclusions —Pretreatment an induces modest, depolarization protects from sI/R injury. The demonstrated reduction uptake possibly reduces overload, providing likely mechanism NO-induced protection.