title: Long-term effect of low energy laser irradiation on infarction and reperfusion injury in the rat heart.
abstract: Low-energy laser irradiation (LELI) has been found to modulate biological processes. The present study investigated the effect of LELI on infarct size after chronic myocardial infarction (MI) and ischemia-reperfusion injury in rats. The left anterior descending (LAD) coronary artery was ligated in 83 rats to create MI or ischemia-reperfusion injury. The hearts of the laser-irradiated (LI) rats received irradiation after LAD coronary artery occlusion and 3 days post-MI. At 14, 21, and 45 days post-LAD coronary artery permanent occlusion, infarct sizes (percentage of left ventricular volume) in the non-laser-irradiated (NLI) rats were 52 +/- 12 (SD), 47 +/- 11, and 34 +/- 7%, respectively, whereas in the LI rats they were significantly lower, being 20 +/- 8, 15 +/- 6, and 10 +/- 4%, respectively. Left ventricular dilatation (LVD) in the chronic infarcted rats was significantly reduced (50-60%) in LI compared with NLI rats. LVD in the ischemia-reperfusion-injured LI rats was significantly reduced to a value that did not differ from intact normal noninfarcted rats. Laser irradiation caused a significant 2.2-fold elevation in the content of inducible heat shock proteins (specifically HSP70i) and 3.1-fold elevation in newly formed blood vessels in the heart compared with NLI rats. It is concluded that LELI caused a profound reduction in infarct size and LVD in the rat heart after chronic MI and caused complete reduction of LVD in ischemic-reperfused heart. This phenomenon may be partially explained by the cardioprotective effect of the HSP70i and enhanced angiogenesis in the myocardium after laser irradiation.
authors.affiliation: Department of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel.
authors.forename: T
authors.initials: T
authors.lastname: Yaakobi
authors.forename: Y
authors.initials: Y
authors.lastname: Shoshany
authors.forename: S
authors.initials: S
authors.lastname: Levkovitz
authors.forename: O
authors.initials: O
authors.lastname: Rubin
authors.forename: S A
authors.initials: SA
authors.lastname: Ben Haim
authors.forename: U
authors.initials: U
authors.lastname: Oron
mesh_terms: D000818:Animals; D015153:Blotting, Western; D003331:Coronary Vessels / Q000502:physiology; D003893:Desmin / Q000096:biosynthesis; D006360:Heat-Shock Proteins / Q000096:biosynthesis; D007150:Immunohistochemistry; D053685:Laser Therapy; D008026:Ligation; D008297:Male; D009203:Myocardial Infarction / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D015428:Myocardial Reperfusion Injury / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D018919:Neovascularization, Physiologic / Q000528:radiation effects; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D003893:Desmin; D006360:Heat-Shock Proteins