Activation of angiogenesis under influence of red low level laser radiation

Abstract

The positive influence of low level laser irradiation (LLLI) on the treatment of vascular disorders, ischemic heart disease, activation of microcirculation, as well as on tissue regeneration and reparation is well known. One of the mechanisms of positive effects of LLLI can be connected with activation of angiogenesis due to direct or indirect influence on stem and endothelial progenitor cells. These cells are responding to the influence of vascular endothelial growth factor (VEGF) and playing a key role in angiogenesis, tissue regeneration and reparation. The aim of the current study is to investigate red low level laser light influence on angiogenesis in vitro, and to compare it influence with effects of VEGF application. Thoracic aortal rings from Sabra rats were used in the study. Samples of group 1 served as control, group 2 samples were incubated with VEGF, group 3 samples were irradiated with low level laser light (660 nm, 20 mW) for 10 min, and group 4 samples were incubated with VEGF after receiving 10 min laser irradiation. The samples were cultivated for 1 week, after that the cultures were fixed with formalin and stained with gencyan violet solution in ethanol. The stained samples were photographed by a camera connected to the microscope. In the control group (1) development of new vessels was not detected. In VEGF group (2) the area covered by new vessels was 1,3 ± 0,24 mm 2 and the maximal length of vessels was 0,93 ± 0,11 mm. In LLLI group (3) − 1,9±0,29 mm 2 and 0,75 ± 0,10 mm accordingly. No statistical significant difference was discovered between groups 2 and 3. In VEGF + LLLI group (4) the area covered by new vessels was 6,98 ± 0,88 mm 2 (p <0,001) and the maximal length of vessels was 1,7 ± 0,23 mm (p <0,001). Study shows, that LLLI initiates the process of angiogenesis in vitro at the same extent as application of VEGF, as well as significantly strengthens effects of VEGF.