Attenuation of infarct size in rats and dogs after myocardial infarction by low-energy laser irradiation

Background and Objective: The aim of the present study was to investigate the possibility that low-energy laser irradiation attenuates infarct size formation after induction of chronic myocardial infarction (MI) in small and large experimental animals. Study Design/Materials and Methods: Laser irradiation was applied to the infarcted area of rats and dogs at various power densities (2.5 to 20 mW/cm(2))after occlusion of the coronary artery. Results: In infarcted laser-irradiated rats that received laser irradiation immediately and 3 days after MI at energy densities of 2.5, 6, and 20 mW/cm(2), there was a 14%, 62% (significant; P<0.05), and 2.8% reduction of infarct; size (14 days after MI) relative to non-laser-irradiated rats, respectively. In dogs, a 49% (significant; P<0.01) reduction of infarct size was achieved. Conclusion: The results of the present study indicate that; delivery of low-energy laser irradiation to infarcted myocardium in rats and dogs has a profound effect on the infarct size after MI. (C) 2001 Wiley-Liss, Inc.