title: Low-power Helium-Neon laser irradiation enhances the expression of VEGF in murine myocardium.
abstract: BACKGROUND
  Low-power helium-neon (He-Ne) lasers have been increasingly widely applied in the treatment of cardiovascular diseases, and its vasodilation effect has been proven. The aim of this study was to determine the effects of low-power He-Ne laser irradiation directed at the precardial region of Wistar rats on capillary permeability in the myocardium and the expression of myocardial vascular endothelial growth factor (VEGF).
  
  
  METHODS
  Sixteen rats were divided randomly into control and irradiated groups (n = 8, each). A He-Ne laser (632.8 nm) was applied to the irradiated group with a dose of 60.5 J/cm(2). Ferritin was perfused into the left femoral vein and capillary permeability was examined under an electron microscope. VEGF expression in the myocardium was investigated by immunohistochemical methods, RT-PCR, and image analysis.
  
  
  RESULTS
  The ultrastructures of the myocardial capillaries were examined. Compared to the control group, more high-density granules (ferritin), which were present within the capillary endothelium and the mitochondrions of myocardial cells in the internal layer of the myocardium, were observed in the irradiated group. VEGF staining of the myocardium was stronger in the irradiated group than that in the control group. The optic density of the irradiated group (0.246 +/- 0.015) was significantly higher than that of the control group (0.218 +/- 0.012, P < 0.05). Finally, the levels of RT-PCR products of VEGF165 mRNA were 2.79 times higher in irradiated rats than in the control rats.
  
  
  CONCLUSIONS
  Our study demonstrates that He-Ne laser irradiation (in doses of 60.5 J/cm(2)) increases myocardial capillary permeability and the production of VEGF in myocardial microvessels and in myocardium. Our study provides experimental morphological evidence that myocardial microcirculation can be improved using He-Ne laser irradiation.
authors.affiliation: Department of Anatomy and Histoembryology, Peking University Health Science Center, Beijing 100083, China. zhangook@yahoo.com.cn
authors.forename: Wei-guang
authors.initials: WG
authors.lastname: Zhang
authors.forename: Chang-yan
authors.initials: CY
authors.lastname: Wu
authors.forename: Wen-xiao
authors.initials: WX
authors.lastname: Pan
authors.forename: Long
authors.initials: L
authors.lastname: Tian
authors.forename: Jia-liu
authors.initials: JL
authors.lastname: Xia
mesh_terms: D000818:Animals; D002199:Capillary Permeability / Q000528:radiation effects*; D005260:Female; D006321:Heart / Q000528:radiation effects*; D007150:Immunohistochemistry; D007834:Lasers; D008854:Microscopy, Electron; D009206:Myocardium / Q000378:metabolism / Q000648:ultrastructure; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis* / Q000235:genetics
chemical_list: D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A