title: Ultraviolet radiation-induced cataract: age and maximum acceptable dose.
abstract: OBJECTIVE
  To investigate the effect of age on ultraviolet radiation-B (UVR-B)-induced cataract and to detect the maximum acceptable dose in rats of different age groups.
  
  
  METHODS
  Four age groups of 20 rats each, aged 3, 6, 10, and 18 weeks, were included. Each age group was divided into five UVR-B dose subgroups. The rats were unilaterally exposed to UVR-B (lambda(max) = 302.6 nm, lambda(0.5) = 4.5 nm). The incident dose on the cornea varied between 0 and 8 kJ/m(2). One week after exposure, the rats were killed, both lenses were extracted, the intensity of forward light-scattering was measured, and photographs were taken. The sensitivity of the lens to UVR-B was estimated as the maximum acceptable dose.
  
  
  RESULTS
  The maximum acceptable dose for 3-, 6-, 10-, and 18-week-old rats was estimated to be 1.4, 2.7, 4.3 and 5.2 kJ/m(2), respectively.
  
  
  CONCLUSIONS
  Young rats were more sensitive to UVR-B than old ones. Age should be considered when estimating the risk for UVR-B-induced cataract.
authors.affiliation: Research Department, St Erik's Eye Hospital, Karolinska Institute, Stockholm, Sweden. xiuqin.dong@ste.ki.se
authors.forename: Xiuqin
authors.initials: X
authors.lastname: Dong
authors.forename: Marcelo
authors.initials: M
authors.lastname: Ayala
authors.forename: Stefan
authors.initials: S
authors.lastname: Löfgren
authors.forename: Per G
authors.initials: PG
authors.lastname: Söderberg
mesh_terms: D000375:Aging / Q000528:radiation effects*; D000818:Animals; D002386:Cataract / Q000209:etiology* / Q000473:pathology; D004307:Dose-Response Relationship, Radiation; D007908:Lens, Crystalline / Q000473:pathology / Q000528:radiation effects*; D020714:Maximum Tolerated Dose; D011829:Radiation Dosage; D011833:Radiation Injuries, Experimental / Q000209:etiology* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014466:Ultraviolet Rays