Photobiomodulation (PBM) is a form of the use of visible red and Near-infrared (NIR) light at low power, where a laser light photon is absorbed at the electronic level, without heat production. PBM can be applied in wide range of treatment to help the wound, inflammation, edema, and pain reduction. However, there is a lack of scientific documentation regarding its actual effects. Objectives: This study assesses the impact of PBM on the release of M1-related cytokine in monocyte cells with particular emphasis on interleukin-1β (IL-1β) and Tumour Necrosis Factor α (TNF-α). Methods: Tamm-Horsfall Protein 1 (THP-1) macrophages M1 cells have been exposed to the light from the diode laser of 850nmat different doses (0, 0.6, 1.2 and 3.6 J/cm2). The release of cytokines was determined by enzyme-linked immunosorbent assay, after different periods of incubation (0, 12, 24, and 48 hours) post-irradiation. The proliferation of fibroblast cells suspended in irradiated M1-supernatent was evaluated for the same periods of incubation. Results: The results showed that PBM significantly enhanced M1-related cytokine release (p < 0.05). Obviously, IL-1β increased post-irradiation at 1.2 J/cm2 more than other doses for all incubation periods. TNF-α was decreased significantly after two days of irradiation (p < 0.005) for all doses. A significant increase in fibroblast proliferation (p < 0.005) was observed concomitant with the boost of cytokine release. Conclusion: This in vitro study has demonstrated that the PBM of the 850 nm diode laser therapy can enhance M1-related cytokine release, which in turn increases the proliferation of fibroblast cells. Moreover, PBM at 850 nm plays an anti-inflammatory role, which manifested by decreasing the level of TNF-α. Therefore, this therapy may be able to accelerate the wound healing process.
