Long-term effect of low energy laser irradiation on infarction and reperfusion injury in the rat heart

Tali Yaakobi, Yariv Shoshany, Sara Levkovitz, Ofer Rubin, Shlomo A. Ben Haim, Uri Oron*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish
Pages (from-to)2411-2419
Number of pages9
JournalJournal of Applied Physiology
Issue number6
StatePublished - Jun 2001


  • Angiogenesis
  • Heat shock proteins
  • Ischemia
  • Laser
  • Myocardial infarction


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