Cardioprotection from Ischemia-Reperfusion Injury by Near-Infrared Light in Rats

Abstract Objective: Myocardial reperfusion injury can induce further cardiomyocyte death and contribute to adverse cardiovascular outcomes after myocardial ischemia, cardiac surgery, or circulatory arrest. Exposure to near-infrared (NIR) light at the time of reoxygenation protects neonatal rat cardiomyocytes and HL-1 cells from injury. We hypothesized that application of NIR at 670 nm would protect the heart against ischemia-reperfusion injury. Methods: We assessed the protective role of NIR in in vivo and in vitro rat models of ischemia-reperfusion injury. Results: NIR application had no effect on the function of the nonischemic isolated heart, and had no effect on infarct size when applied during global ischemia. In the in vivo model, NIR commencing immediately before reperfusion decreased infarct size by 40%, 33%, 38%, and 77%, respectively, after regional ischemic periods of 30, 20, 15, and 10 min. Serum cardiac troponin I (cTnI) was significantly reduced in the 15 min group, whereas creatine kinase (...