Phagocytosis and subsequent degradation of pathogens by macrophages play a pivotal role in host innate immunity
in mammals. Laser irradiation has been found to produce photobiological effects with evidence of interference with
immunological functions. However, the effects of laser on the immune response have not been extensively characterized.
In this study, we focused our attention on the effects of He-Ne laser on the phagocytic activity of macrophages by using
flow cytometry (FCM). After irradiating at fluence of 0, 1, 2 J/cm2 with He-Ne laser (632.8 nm, 3mw), the cells were
incubated with microsphere and then subjected to FACS analysis. The results showed that Low-power laser irradiation
(LPLI) leads to an increase in phagocytosis on both mouse peritoneal macrophages and the murine macrophage-like cell
line RAW264.7. In addition, we demonstrated that LPLI increased phagocytosis of microsphere in a dose-dependent
manner, reaching a maximum at fluence of 2 J/cm2. Taken together, our results indicated that Low-power laser
irradiation with appropriate dosage can enhance the phagocytosis of macrophage, and provided a theoretical base for the
clinical use of the He-Ne laser.