Effects of Diode Laser Irradiation on Angiogenesis

Abstract

Angiogenesis is an important and interesting subject in dentistry. However, few studies on angiogenesis by low power laser irradiation have been performed in vivo.
In this study, the effects of low power laser irradiation on angiogenesis of human endothelial cells were investigated in vitro. The behavior of angiogenetic factors was examined by ELISA and confocal laser scanning microscopy.
Growth factors (VEGF, angiopoietin-1, angiopoietin-2) localized at endoplasmic reticulum in the endothelial cells and their receptors (Flt-1, KDR/Flk-1, Tie-2) appeared on cell membranes. In addition, adhesive molecules (VE-cadherin, beta-catenin) were visible at regions of cell to cell contact.
After the irradiation, their expressions were enhanced except angiopoietin-2. Each of the amounts of the proteins increased compared to the control. VEGF-VEGFR, VE-cadherin and beta-catenin, and Angiopoietin-Tie were activated by the laser irradiation. Cell proliferation, mitogen, adhesion and vessel formation were promoted.
These results suggest that low power laser irradiation promotes angiogenesis to activate not only the endothelial cells but also expressions of growth factors and adhesive molecules.