Background: Regarding recent findings on the proven influence of laser light on healing and endothelial regeneration processes, this study was conducted in order to examine the influence of low-power laser illumination on the endothelial inflammatory response.
Materials and methods: Human umbilical vein endothelial cells (HUVECs) isolated from umbilical cord, cultured in standard conditions, were harvested and passaged in 24-well plates. Laser influence on HUVEC inflammatory response was measured by stimulating them with Interleukin-1β (IL-1β) followed by laser light illumination. A 808-nm wave length laser diode and light energy doses of 1.5 and 4.5 J/cm(2) were used (50 mW for 90 and 270 s respectively). The response was measured by assessing Cluster of differentiation 54 (CD54), Cluster of differentiation 62E (CD62E), Monocyte chemotactic protein-1 (MCP-1) expression and von Willebrand factor (vWF) release, at 6 and 24 h after stimulation. The MCP-1 and vWF activity in cell supernatants was measured with an enzyme-linked immunosorbent assay (ELISA) kit. Cytofluorometry was used to assess CD54 and CD62E expression.
Results: MCP-1 concentration in supernatants from HUVECs was significantly lower 6 h after 4.5 J/cm(2) stimulation compared to IL-1β-stimulated cells. No changes in MCP-1 levels after IL-1β stimulation plus 1.5 J/cm(2) illumination, compared to IL-1β stimulated HUVECs were noted. IL-1β stimulation significantly enhanced the concentration of vWF and the expression of CD54 and CD62E. Both energies of laser light illumination inhibited the IL-1β-induced increase of CD54 and CD62E concentration. vWF activity after illumination was comparable to that of unstimulated cells. There were no significant differences in the viable cell count between the groups tested.
Conclusion: Low-power laser illumination diminishes the pro-inflammatory and pro-coagulant activity of IL-1β-stimulated HUVECs.