title: Retinal degeneration induced in adult mice by a single intraperitoneal injection of N-ethyl-N-nitrosourea.
abstract: Seven-week-old female BALB/c mice received a single intraperitoneal injection of N-ethyl-N-nitrosourea (ENU) (50, 100, 200, 400, or 600 mg/kg), and retinal damage was evaluated after 7 days. Sequential morphological features of the retina and retinal apoptosis, as determined by the TUNEL assay, were analyzed 6, 12, 24, and 72 hr and 7 days after treatment with 600 mg/kg of ENU. Moreover, older mice (25 to 34 weeks of age) received an intraperitoneal injection of 600 mg/kg ENU and were sacrificed 7 days later. All animals were necropsied, and both eyes were examined histopathologically. Two of the 5 mice that received 600 mg/kg ENU died during the experimental period. Histopathologically, all mice that received 600 mg/kg of ENU experienced retinal degeneration characterized by the loss of photoreceptor cells (disappearance of the outer nuclear layer and photoreceptor layer) in both the central and peripheral retina within 7 days. One of 5 mice treated with 400 mg/kg ENU exhibited retinal damage that was restricted to the central retina. Older mice treated with 600 mg/kg ENU exhibited retinal damage that was similar to the retinal damage in younger mice. In the 600 mg/kg ENU-treated mice, TUNEL-positive photoreceptor cells peaked 72 hr after ENU treatment. Retinal thickness and the photoreceptor cell ratio in the central and peripheral retina were significantly decreased, and the retinal damage ratio was significantly increased 7 days after treatment. In conclusion, ENU induces retinal degeneration in adult mice that is characterized by photoreceptor cell apoptosis.
authors.affiliation: Department of Pathology II, Kansai Medical University, Moriguchi, Osaka, Japan. yoshizak@takii.kmu.ac.jp
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Yoshizawa
authors.forename: Maki
authors.initials: M
authors.lastname: Kuro-Kuwata
authors.forename: Tomo
authors.initials: T
authors.lastname: Sasaki
authors.forename: Yen-Chang Clark
authors.initials: YC
authors.lastname: Lai
authors.forename: Sayaka
authors.initials: S
authors.lastname: Kanematsu
authors.forename: Hisanori
authors.initials: H
authors.lastname: Miki
authors.forename: Ayako
authors.initials: A
authors.lastname: Kimura-Kawanaka
authors.forename: Norihisa
authors.initials: N
authors.lastname: Uehara
authors.forename: Takashi
authors.initials: T
authors.lastname: Yuri
authors.forename: Airo
authors.initials: A
authors.lastname: Tsubura
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005038:Ethylnitrosourea / Q000633:toxicity*; D005260:Female; D020287:In Situ Nick-End Labeling / Q000379:methods; D007274:Injections, Intraperitoneal; D051379:Mice; D008807:Mice, Inbred BALB C; D020419:Photoreceptor Cells, Vertebrate / Q000187:drug effects / Q000473:pathology; D012160:Retina / Q000187:drug effects; D012162:Retinal Degeneration / Q000139:chemically induced* / Q000473:pathology*
chemical_list: D005038:Ethylnitrosourea