Effect of Low-Level Er: YAG (2940 nm) laser irradiation on the photobiomodulation of mitogen-activated protein kinase cellular signaling pathway of rodent cementoblasts

Abstract

Backgrounds: Dental avulsion due to trauma, especially in young patients, is a worldwide problem, requiring tooth replacement. Delayed replantation could cause tooth loss when the cementum is severely damaged. A small number of studies has reported that photobiomodulation (PBM) therapy using Er: YAG laser irradiation activates cellular signaling responses in different cell types, resulting in a variety of favorable biological effects. The aim of this in vitro study was to evaluate the potential biostimulatory effect of low-level Er: YAG laser irradiation on the biological responses of cultured mouse cementoblasts (OCCM-30), including the mitogen-activated protein kinases (MAPKs).

Methods: OCCM-30 cells were exposed to 2940 nm Er: YAG laser irradiation for 15 s at 0.34 W (pulse duration of 100 or 1000 μs, 17 mJ/pulse) at energy densities of 1 or 2 J/cm². Irradiated and non-irradiated OCCM-30 cells were tested for migration (Scratch assay), proliferation (MTS assay) and functional differentiation (Alizarin Red S assay). Lumican (Lum) and Fibromodulin (Fmod) gene expression, and activation of MAPKs, were assessed by RT-PCR and Western blotting, respectively.

Results: Low-level Er: YAG laser irradiation at 2 J/cm² and pulse duration of 1000 μs resulted in the highest migration rate and proliferation. Moreover, the pulse duration irradiation of 100 μs increased Lum expression. Fmod expression was increased after 1000 μs pulse duration laser stimulation. Low-level Er: YAG laser irradiation increased the mineralization of OCCM-30 cells after 7 days and activated ERK1/2, P38 and JNK signaling.

Conclusions: Low-level Er: YAG laser irradiation induces OCCM-30 cell migration, proliferation and differentiation, and activates the MAPK signaling pathway.

Keywords: Cementoblasts; Cementogenesis; Er: YAG laser; MAPK; Migration; Proliferation.