title: Correlation between high-resolution optical coherence tomography (OCT) images and histopathology in an N-methyl-N-nitrosourea-induced retinal degeneration rat model.
abstract: BACKGROUND
  Recent research on macular diseases has prompted investigations into the condition of the intersection between the inner and outer segments (IS/OS), and its relationship with retinal photoreceptor abnormalities. Because the correlation between optical coherence tomography (OCT) images and histopathology is unclear, the authors compared them in an N-methyl-N-nitrosourea (MNU)-induced photoreceptor degeneration rat model.
  
  
  METHODS
  MNU (60 mg/kg), which is toxic to photoreceptors, was injected in 12 Brown Norway rats. After MNU administration, three rats were used per histopathological study 3 h, 6 h, 24 h and 1 week after the injections. Two healthy rats served as controls. OCT images were taken before euthanisation.
  
  
  RESULTS
  3 h after the MNU injections, the IS and OS were oedematous, but the IS/OS borderline was recognised histopathologically, and the IS/OS was depicted on the OCT images. Six hours after injections, the OS were preserved, but the IS structures were destroyed or partially disorganised histopathologically, and the IS/OS was not observed on the OCT images. Twenty-four hours after the injections, the IS and OS were totally disorganised histopathologically, and the IS/OS was not depicted on the OCT images.
  
  
  CONCLUSIONS
  The IS structure might be the origin of the IS/OS on OCT images.
authors.affiliation: Department of Ophthalmology, Tokyo Medical University Hospital, 6-7-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo 160-0023, Japan. phthisis@nifty.com
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Yamauchi
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kimura
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Agawa
authors.forename: Rintaro
authors.initials: R
authors.lastname: Tsukahara
authors.forename: Maki
authors.initials: M
authors.lastname: Mishima
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Yamakawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Goto
mesh_terms: D000477:Alkylating Agents / Q000633:toxicity; D000818:Animals; D004195:Disease Models, Animal; D008770:Methylnitrosourea / Q000633:toxicity*; D020419:Photoreceptor Cells, Vertebrate / Q000187:drug effects / Q000473:pathology*; D051381:Rats; D011914:Rats, Inbred BN; D012160:Retina / Q000187:drug effects / Q000473:pathology; D012162:Retinal Degeneration / Q000139:chemically induced* / Q000473:pathology*; D013997:Time Factors; D041623:Tomography, Optical Coherence
chemical_list: D000477:Alkylating Agents; D008770:Methylnitrosourea