Laser-induced osteoblast proliferation is mediated by ROS production

Abstract

Low-level laser therapy (LLLT) is widely used in regenerative medicine and in dental therapy by virtue of its beneficial effects in a plethora of pathological conditions. In this study, the effect of a 980 nm diode laser on pre-osteoblasts proliferation has been evaluated, along with reactive oxygen species (ROS) production. We hypothesized that ROS were a key factor in LLLT-induced pre-osteoblasts proliferation, as it is known that ROS can induce the activation of many biological pathways, leading to cell proliferation, differentiation or apoptosis. Murine pre-osteoblasts MC3T3 cells were irradiated with different energy outputs (1-50 J) in the absence or presence of the antioxidant N-Acetyl-L-cysteine (NAC). Laser treatment, in the absence of NAC, was able to induce a fluence-dependent statistically significant increase in ROS generation, while the presence of NAC strongly inhibited it. Cell proliferation, measured after laser stimulation, was significantly increased both at low and higher energy, with a peak at 10 J in the absence of the antioxidant. On the contrary, in the presence of NAC, laser irradiation was not able to induce any cell proliferation, suggesting a crucial role of ROS in this laser-induced cell effect. These results suggest that LLLT may be a useful tool for bone regeneration therapy and an effective range of fluences to be used is indicated.

Biological effects of low-level laser irradiation on umbilical cord mesenchymal stem cells

“…20 Furthermore, Bouvet-Gerbettaz et al 21 reported that infrared LLLI at 808 nm could not alter murine bone progenitor cell proliferation and differentiation. Migliario et al 18 reported that although pre-osteoblast proliferation was significantly increased after exposure to low or higher energy, cell proliferation was not promoted at 50 J of irradiation. Taken together, these findings indicate that the biological effects of laser irradiation rely on the parameters of the light source, including laser wavelength, output power density, energy density, and pulse structure.…”

“…[24][25][26] The physiological cell activation at low ROS concentrations is mediated by the activation of transcription factors and the promotion of cell proliferation and differentiation. Cells generate low levels of ROS after LLLI, whereas high-energy laser irradiation induces high levels of ROS, 18,25 which may lead to chronic oxidative stress in cells. The oxidative damage can then inhibit cell proliferation and induce apoptosis.…”

Low level laser therapy reduces acute lung inflammation without impairing lung function

“…Several molecular targets have been described. LLLT seems to enhance the electron flow through the respiratory chain in the mitochondria, as a result from photon acceptance on cytochrome c oxidase, leading to increased production of reactive oxygen species (ROS) [3]; as a consequence of this redox signaling imbalance, the transcription factors HIF-1α, NRF2 and NF-κB may be activated, leading to a massive genic response [4] directed to inflammation, repair and proliferation [5][6][7]. Also in the mitochondria, LLLT may enhance the membrane potential * Corresponding author: e-mail: viviancury@usp.br, Phone: (55-11) 3061-8480, Fax: (55-11) 3061-7170 Acute lung injury is a condition characterized by exacerbate inflammatory reaction in distal airways and lung dysfunction.…”

Photodynamic Therapy with Pyoktanin Blue and Diode Laser for Elimination of Enterococcus faecalis

“…Adequate laser power can increase the activity of bacteria and cells. However, too much power causes damage to the bacteria and cells (24)(25)(26). Biostimulatory effects of laser are governed by the Arndt-Schulz law of biology, i.e., weak stimuli excite physiological activity, whereas strong stimuli retard it (27).…”