title: Influence of blue light on photoreceptors in a live retinal explant system.
abstract: OBJECTIVE
  The present study was performed to investigate the early effects of blue light irradiation of photoreceptors in retinal explant cultures.
  
  
  METHODS
  Murine retinal explant cultures were irradiated with visible blue light (405 nm) with an output power of 1 mW/cm2. Dihydroethidium was used to determine the production of reactive oxygen species. Morphological alterations of photoreceptor outer segments were determined by live imaging microscopy with mitochondrial dye JC-1. Transmission and scanning electron microscopy were used for ultrastructural evaluations. Cell death in the retina was assessed by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL) assay method.
  
  
  RESULTS
  Live retinal explants displayed an increase in reactive oxygen species production, as revealed by fluorescent dihydroethidium products in photoreceptor cells after 30 min of blue light exposure. After 3 h of exposure, blue light caused disorganization of the normally neatly stacked outer segments of living photoreceptors. Ultrastructural analysis revealed breaks in the cell membrane surrounding the outer segments, especially in the middle section. The outer segments appeared tortuous, and the lamellar structures had been disrupted. TUNEL-staining revealed that long-term blue light exposure induced photoreceptor cell death.
  
  
  CONCLUSIONS
  In vitro blue light irradiation of retinal explants is a suitable model system for investigating early ultrastructural changes, as well as damage that leads to cell death in photoreceptor cells.
authors.affiliation: Institute of Anatomy, TU Dresden, Dresden, Germany.
authors.forename: Cora
authors.initials: C
authors.lastname: Roehlecke
authors.forename: Ulrike
authors.initials: U
authors.lastname: Schumann
authors.forename: Marius
authors.initials: M
authors.lastname: Ader
authors.forename: Lilla
authors.initials: L
authors.lastname: Knels
authors.forename: Richard H W
authors.initials: RH
authors.lastname: Funk
mesh_terms: D000818:Animals; D001562:Benzimidazoles / Q000032:analysis; D002232:Carbocyanines / Q000032:analysis; D016923:Cell Death / Q000528:radiation effects; D004996:Ethidium / Q000031:analogs & derivatives / Q000032:analysis; D005260:Female; D005456:Fluorescent Dyes / Q000032:analysis; D020287:In Situ Nick-End Labeling; D008027:Light / Q000009:adverse effects*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D009924:Organ Culture Techniques / Q000379:methods; D020419:Photoreceptor Cells, Vertebrate / Q000378:metabolism / Q000528:radiation effects / Q000648:ultrastructure; D017382:Reactive Oxygen Species / Q000378:metabolism; D012160:Retina / Q000378:metabolism / Q000528:radiation effects / Q000648:ultrastructure
chemical_list: D001562:Benzimidazoles; D002232:Carbocyanines; D005456:Fluorescent Dyes; D017382:Reactive Oxygen Species; C067883:dihydroethidium; C068624:5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine; D004996:Ethidium