Effects of 810 nm and 940 nm Diode Laser on ROS Production in Macrophages: The Role of Interferon-Gamma

Background: Reactive oxygen species (ROS) are critical molecules produced during cellular metabolism. Macrophages, as essential immune cells, play a pivotal role in the immune response by producing inflammatory mediators and releasing ROS. Interferon-gamma (IFN-γ) is a key stimulator of macrophage activity, enhancing ROS production. Objectives: With the increasing application of low-level laser therapy (LLLT) in medicine, this study aims to compare the effects of 810 nm and 940 nm diode laser irradiation on ROS production in macrophages. Methods: This in vitro study utilized a monocyte/macrophage cell line. Cells were seeded into microwell plates and exposed to diode laser irradiation at 810 nm and 940 nm, with power settings of 0.4 watts (energy density 7 - 15 J/cm2) and irradiation times of 15 and 30 seconds. The IFN-γ was added post-irradiation. The ROS production was assessed using a fluorometric method, measuring nitric oxide (NO) as an indirect indicator. Results: The comparison between 810 nm and 940 nm wavelengths showed no significant difference in ROS production (P > 0.05). However, higher energy density (4 J vs. 2 J, P = 0.001), longer irradiation time (30 s vs. 15 s, P = 0.001), and the presence of IFN-γ (P < 0.001) significantly increased ROS levels. Conclusions: This study showed that both 810 nm and 940 nm diode lasers significantly increase ROS production in macrophage cells compared to a control group, despite no significant differences between the two wavelengths.