title: Irradiation at 634 nm releases nitric oxide from human monocytes.
abstract: Previous studies have shown that irradiation at 634 nm decreases the release of extracellular reactive oxygen species (ROS) without affecting viability in human monocytes. Here, we examined the effect of irradiation at 634 nm on the release of nitric oxide (NO), activation of inducible nitric oxide synthase (iNOS) and endothelial NOS (eNOS), and release of intracellular ROS. Chemiluminescence assays were used to measure NO release, intracellular ROS, and adenosine triphosphate levels (to assess cell viability). Levels of iNOS and eNOS mRNA were analyzed using PCR. Irradiation resulted in elevated levels of NO but had no effect on iNOS or eNOS. Irradiation also caused a decrease in levels of intracellular ROS and had no effect on cell viability. Our studies indicate that irradiation at 634 nm releases NO, possibly from a preformed store, and reduces the production of intracellular ROS without affecting cell viability. Irradiation at 634 nm may have a wide range of clinical applications, including a reduction in oxidative stress-mediated injury in the vasculature.
authors.affiliation: Wallenberg Laboratory, Sahlgrenska University Hospital, Göteborg University, Gothenburg, 413 45, Sweden.
authors.forename: Ann
authors.initials: A
authors.lastname: Lindgård
authors.forename: Lillemor Mattsson
authors.initials: LM
authors.lastname: Hultén
authors.forename: Lennart
authors.initials: L
authors.lastname: Svensson
authors.forename: Bassam
authors.initials: B
authors.lastname: Soussi
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis; D006801:Humans; D028022:Low-Level Light Therapy; D009000:Monocytes / Q000378:metabolism* / Q000528:radiation effects*; D009569:Nitric Oxide / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D000255:Adenosine Triphosphate