title: Visible light promotes interleukin-10 secretion by sublethal fluences.
abstract: OBJECTIVE
  To determine the effect of blue light on cultured splenocyte viability and secretion of cytokines involved in the regulation of immune responses in the inflammatory process.
  
  
  BACKGROUND
  Previous studies showed that red light has various effects on lymphocyte proliferation and production of cytokines.
  
  
  METHODS
  Cultured mouse splenocytes were exposed to visible light (wavelengths, 450-490 nm) using 2-108 J/cm(2), with and without scavengers of reactive oxygen species (ROS). One half of the samples were stimulated by the heat-killed periopathogenic bacterium Porphyromonas gingivalis. Following incubation for 48 h, the levels of the cytokines interleukin-10 (IL-10), tumor necrosis factor alpha (TNFα), and interferon gamma (IFNγ) were analyzed, and the viability of the cells was tested using the XTT assay. The total oxidant-scavenging capacity of the nonexposed and exposed splenocytes to light was determined by a chemiluminescence assay, and the temperature of the cell culture medium was measured after light exposure.
  
  
  RESULTS
  Exposure to blue light at fluences of 27-108 J/cm(2) caused a decrease in splenocyte viability. Lower fluences increased the secretion of cytokine IL-10, which was abolished by ROS scavengers. Exposure to light had no effect on the secretion of cytokines TNFα and IFNγ. Following exposure to light, more ROS were detected and the temperature measured did not exceed 30.7°C.
  
  
  CONCLUSIONS
  Blue light had a stimulatory effect on cell secretion of IL-10, mediated by ROS. Therefore, an increase in IL-10 might be a potential method for modulating the inflammatory processes of local disorders, such as periodontitis and arthritis.
authors: Department of Prosthodontics, The Hebrew University-Hadassah School of Dental Medicine, Jerusalem, Israel. osnatf@ekmd.huji.ac.il
authors: Osnat
authors: O
authors: Feuerstein
authors: Rawi
authors: R
authors: Assad
authors: Erez
authors: E
authors: Koren
authors: Isaac
authors: I
authors: Ginsburg
authors: Ervin I
authors: EI
authors: Weiss
authors: Yael
authors: Y
authors: Houri-Haddad
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques; D002470:Cell Survival / Q000528:radiation effects; D007371:Interferon-gamma / Q000378:metabolism / Q000528:radiation effects; D016753:Interleukin-10 / Q000378:metabolism* / Q000528:radiation effects; D008027:Light; D051379:Mice; D017382:Reactive Oxygen Species / Q000378:metabolism / Q000528:radiation effects; D013154:Spleen / Q000378:metabolism* / Q000473:pathology / Q000528:radiation effects*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000528:radiation effects
chemical_list: D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D007371:Interferon-gamma