Abstract
Abstract: :
Purpose: To investigate the effect of age on ultraviolet radiation-B (UVR-B) induced cataract. To establish safety limits for UVR-B induced cataract in an in vivo rat model. Methods: Female Sprague-Dawley rats were included in seven age-groups: 3, 6, 10, 18, 26, 40, and 60 weeks. Each age group was further subdivided into 5 dose sub-groups. The rats were unilaterally exposed to UVR-B. The incident doses on the cornea ranged from 0 to 9.2 kJ/m2. The rats were sacrificed and the lenses were extracted one week after UVR-B exposure. Intensities of forward light scattering were measured and photographs were taken. The safety limit for UVR-B induced cataract for different age groups was estimated by the maximum tolerable dose (MTD) concept, based on the dose response curve of each age group. Results: TDs estimated for 3, 6, 10, 18, 26, 40 and 60 weeks old rats were 1.8, 2.5, 4.7, 6.1, 6.5, 6.4,and 6.8 kJ/m2, respectively. Conclusion: Younger rats are more sensitive to UVR-B than older rats. Age should be considered for safety limit estimation for UVR-B induced cataract.
Keywords: 338 cataract • 537 radiation damage: light/UV • 316 animal model