title: Polyamine system in developing rat eye and an animal model of retinopathy of prematurity.
abstract: BACKGROUND
  In experimental models of retinopathy of prematurity (ROP), a vasoproliferative disorder of the retina, retinal lesions are usually assessed by morphological examination. However, studies suggest that the polyamine system may be useful in monitoring proliferation processes. For this reason, polyamine concentrations in rat erythrocytes (RBC) and the regulation of polyamine system in rat eyes under the conditions relevant to ROP were investigated.
  
  
  METHODS
  Newborn Wistar rats were reared in room air (control) or exposed first to hyperoxia (60% or 80% oxygen, 2 weeks) and then to normoxia (relative hypoxia, 1 or 2 weeks). Blood was collected from orbital vessels at 2 weeks of age and before death. Polyamine system-related enzyme activities were measured in retina and lens with radioassays. Polyamines were quantified by fluorometry after extraction, dansylation and HPLC separation.
  
  
  RESULTS
  Oxygen (80% only) significantly decreased RBC polyamine concentrations, which then markedly increased after rats were transferred for a week to normal air, suggesting retardation of growth processes and compensatory stimulation, respectively. However, polyamine system changes in the rat eye were not so pronounced. Enzyme activities and polyamine concentrations tended to be lower in retina after hyperoxia and were only slightly higher, with the exception of ornithine decarboxylase, after a subsequent 1 week of normoxia. In litters subjected to normoxia for longer periods no changes were found.
  
  
  CONCLUSIONS
  The transient and short-lived alteration in polyamine metabolism, especially in the eye, suggests that exposure of newborn rats to high oxygen supplementation followed by normoxia does not necessarily result in marked retinopathy.
authors.affiliation: Division of Ophthalmology, Research Institute Polish Mother's Memorial Hospital, Rzgowska 281/289, PL-93-338 Lodz, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Gralek
authors.forename: K
authors.initials: K
authors.lastname: Sasiak
authors.forename: A
authors.initials: A
authors.lastname: Wojcik
authors.forename: T A
authors.initials: TA
authors.lastname: Gardiner
authors.forename: W A
authors.initials: WA
authors.lastname: Fogel
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development* / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism; D005123:Eye / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D006801:Humans; D018496:Hyperoxia / Q000201:enzymology; D007231:Infant, Newborn; D009955:Ornithine Decarboxylase / Q000378:metabolism; D010100:Oxygen / Q000494:pharmacology; D011073:Polyamines / Q000097:blood / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000201:enzymology / Q000378:metabolism; D012178:Retinopathy of Prematurity / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology
chemical_list: D011073:Polyamines; D009955:Ornithine Decarboxylase; D010100:Oxygen