Generation of superoxide by stimulation of human neutrophils with visible light

Abstract

Objective: Patients who undergo hemodialysis with shielding from light reportedly show lower oxidative stress. To elucidate the mechanism of this effect, we examined the generation of reactive oxygen species during the irradiation of human neutrophils with visible light.
Methods: A suspension of human neutrophils was irradiated for 60 minutes with visible light from a fluorescent lamp (light intensity at the suspension surface: 14, 000lux). Formation of superoxide in the irradiated suspension and a light-shielded control suspension was estimated based on a change in the absorbance of cytochrome C.
Results: The rate of superoxide formation in the irradiated suspension was 2.02nmol⋅10⁶cells/mL/min, while that in the light-shielded control suspension was 0.79nmol⋅10⁶cells/mL/min.
Conclusion: Shielding from light during hemodialysis is likely to reduce the generation of superoxide by visible light stimulation of neutrophils in the circulating blood.