title: [The toxic effect of N-methyl-N- nitrosourea on retina in rats].
abstract: OBJECTIVE
  To observe the toxic effect of N-methyl-N-nitrosourea (MNU) on photoreceptor cells within retina of SD rats.
  
  
  METHODS
  At 50 days of age, 100 female rats received a single intraperitoneal injection of MNU at different doses of 50 mg/kg, 60 mg/kg, 70 mg/kg and 80 mg/kg body weight, respectively. Each group had 6 rats and 4 untreated rats were used as normal control. At 24, 48 and 72 hours and 7 days after the administration of MNU, the animals were sacrificed and both eyes were enucleated immediately and processed for histological examination.
  
  
  RESULTS
  It was found that all doses of MNU could sequentially damage the central and peripheral retina. The first evidence of retinapathy 24 hours after the application of MNU was pyknosis and disruption of photoreceptor cells nuclei and the disorientation of the photoreceptor outer segments; loss of photoreceptor cell deteriorated significantly at 48 hours or 72 hours; the outer nuclear layer and photoreceptor layer were almost completely lost at 7 days.
  
  
  CONCLUSIONS
  The results demonstrated that MNU could selectively damage the photoreceptor cells in the retina of the rats, which was dose-dependent and time-dependent.
authors.affiliation: Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China.
authors.forename: Jinnan
authors.initials: J
authors.lastname: Yang
authors.forename: Shaochun
authors.initials: S
authors.lastname: Lin
authors.forename: Shixing
authors.initials: S
authors.lastname: Hu
authors.forename: Kang
authors.initials: K
authors.lastname: Chen
authors.forename: Xinguo
authors.initials: X
authors.lastname: Deng
mesh_terms: D000818:Animals; D005260:Female; D008770:Methylnitrosourea / Q000008:administration & dosage / Q000633:toxicity*; D020419:Photoreceptor Cells, Vertebrate / Q000187:drug effects* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000187:drug effects / Q000473:pathology
chemical_list: D008770:Methylnitrosourea