Effects of Gaalas Diode Laser on Serum Opsonic Activity Assessed by Neutrophil-Associated Chemiluminescence

The purpose of this study was to investigate the effects of low level laser therapy (LLLT: GaAlAs diode laser: 830 nm) on serum opsonic activity, which was assessed by neutrophil-associated chemiluminescence (CL) responses to zymosan opsonized with sera irradiated in vitro with various doses of LLL. We used both lucigenin-dependent CL (LgCL) for superoxide (O₂^-) detection and luminol-dependent CL (LmCL) which detects myeloperoxidase (MPO)-dependent formation of hypochlorous acid in combination with an MPO inhibitor, sodium azide (NaN₃). When serum opsonic activity was assessed by LgLC, NaN₃ markedly enhanced the responses, suggesting that O₂^- accumulates due to the MPO blockade, leading to the excitation of LgCL. However, LLL-irradiation had no effects on serum opsonic activity. On the other hand, when serum opsonic activity was assessed by LmCL, NaN₃ strongly inhibited the response. The effects of LLLT at different output powers were characterized by similar values, but significantly higher values were observed at the highest dose tested (60 mW for 1 min) in the absence of NaN₃. Since this enhancement effect disappeared in the presence of NaN₃, it was suggested that high dose LLL-irradiation probably activates opsonic activity by facilitating the degranulation of MPO from neutrophils. However, lower doses similar to those used for therapeutic purposes had no effects at any output powers tested.