IN VITORO EFFECTS OF THERAPEUTIC LASER ON SUPEROXIDE GENERATION FROM RAT ALVEOLAR MACROPHAGE

抄録

We studied the effects of low intensity lasers on the production of reactive oxygen species by phagocytes in vitro, in order to explore some of the therapeutic mechanism of laser photostimulation. Rat alveolar macrophages (AMs) were treated with various doses of 830 nm laser before and after incubation. We used lucigenin-dependent chemiluminescence and the cytochrome C reduction method to determine superoxide generation and NADPH oxidase activity, respectively. After incubation, laser treatment (LT), using 60 mW for 10 or 15 s, or 80 mW for 15 s, significantly accelerated peak time (PT) of chemiluminescence without any significant effect on peak height (PH) (P < 0.05, P < 0.001, and P < 0.01, respectively). In contrast, treatment with 150 mW LT for 5, 10 and 15s significantly delayed the process (P < 0.05, P < 0.001, and P < 0.01, respectively). Furthermore, LT with doses higher than 60 mW suppressed NADPH oxidase activity before incubation. Treatment of the macrophages with 30 mW for 10 or 15 s, 40 mW for 15 s, and 60 mW for 5 or 15 s significantly accelerated PT (P < 0.05 in each case). Similarly, there was a significant increase in PH when AMS were treated with 60 mW for 10 s or 80 mW for 10 or 15 s (P < 0.05 in each case), but these dose levels had no significant effect on NADPH oxidase activity. These results indicate that laser photostimulation can modulate AM function, and that the effect does not depend on the total amount of energy applied, i.e., the output power multiplied by the treatment time. Furthermore, our results show that 60 mW is a suitable output power for activating AMS.