title: Phototoxicity of indocyanine green and Brilliant Blue G under continuous fluorescent illumination on cultured human retinal pigment epithelial cells.
abstract: OBJECTIVE
  We  compared the phototoxicity of indocyanine green (ICG) and Brilliant Blue G (BBG) in cultured RPE cells under fluorescent lamp illumination imitating ambient light.
  
  
  METHODS
  Cultured human RPE line cells were stained with ICG or BBG solution at concentrations of clinical use, and cultured in a colorless medium for 24 hours in the dark or under illumination from a fluorescent lamp. After culture, cell morphology and TUNEL-positive apoptotic cells were observed. Cell viability and cell death rate were evaluated. Absorption spectral changes of BBG before and after incubation were measured.
  
  
  RESULTS
  ICG-stained cells cultured under illumination changed to an oval morphology with increased number of apoptotic cells, whereas ICG-stained cells cultured in the dark, and BBG-stained cells cultured under illumination and dark conditions maintained a flat morphology without increase in apoptotic cells. Cell viability decreased and cell death rate increased only in cells stained by ICG followed by culture under illumination. Staining cells with ICG at one-tenth concentration of clinical usage induced no cytotoxicity after culture under illumination. Approximately 30% of total BBG retained in the stained cells was released into the culture supernatant after incubation for 24 hours. The absorption spectrum of BBG did not change after fluorescent light irradiation.
  
  
  CONCLUSIONS
  Illumination with a fluorescent lamp caused cell death via apoptosis in ICG-exposed, but not in BBG-exposed cultured RPE cells. BBG may be a safer dye than ICG because of low light-induced cytotoxicity and rapid elution from stained cells.
authors.affiliation: Department of Ophthalmology, National Defense Medical College, Saitama, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Takayama
authors.forename: Tomohito
authors.initials: T
authors.lastname: Sato
authors.forename: Yoko
authors.initials: Y
authors.lastname: Karasawa
authors.forename: Shunichi
authors.initials: S
authors.lastname: Sato
authors.forename: Masataka
authors.initials: M
authors.lastname: Ito
authors.forename: Masaru
authors.initials: M
authors.lastname: Takeuchi
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D002470:Cell Survival; D002478:Cells, Cultured; D004396:Coloring Agents / Q000009:adverse effects; D006801:Humans; D020287:In Situ Nick-End Labeling; D007208:Indocyanine Green / Q000009:adverse effects*; D008027:Light / Q000009:adverse effects*; D055213:Retinal Pigment Epithelium / Q000187:drug effects* / Q000473:pathology / Q000528:radiation effects*; D012394:Rosaniline Dyes / Q000009:adverse effects*
chemical_list: D004396:Coloring Agents; D012394:Rosaniline Dyes; D007208:Indocyanine Green; C004692:coomassie Brilliant Blue