Phototherapy with low-level laser influences the proliferation of endothelial cells and vascular endothelial growth factor and transforming growth factor-beta secretion.

The healing process and the angiogenesis associated with it, is a very important but currently poorly understood area. Low level laser therapy (LLLT) has been reported to modulate the process of tissue repair by stimulation of cellular reaction such as migration, proliferation, apoptosis and cellular differentiation. The aim of this work was to evaluate the influence of laser radiation in the range of visible and infrared light on the proliferation of vascular endothelial cells in vitro and the secretion of angiogenic factors: vascular endothelial growth factor (VEGF)-A and transforming growth factor (TGF)-β. Vascular human endothelial cells (Ecs) were exposed to radiation with laser beam of the wavelengths: 635 nm (1.875 mW/cm²) and 830 nm (3.75 mW/cm²). Depending on the radiation energy density, the experiment was conducted in four groups : I) the control group (no radiation, 0 J/cm²); II) 635 nm - the energy density was 2 J/cm²; III) 635 nm - 4 J/cm²; IV635 nm - 8 J/cm², II) 830 nm - the energy density was 2 J/cm²; III) 830 nm - 4 J/cm²; IV) 830 nm - 8 J/cm². The proliferation and concentration of VEGF-A and TGF-β were examined. LLLT with wavelength 635 nm increases endothelial cell proliferation. Significant increase in endothelial cell proliferation and corresponding decrease in VEGF concentration may suggest the role for VEGF in this process. The wavelength of 830 nm was associated with a decrease in TGF-β secretion.