Age as a Determinant in the Modulation of Radiation-Induced Cataractogenesis by Estrogen

Abstract

Purpose: : Exposure to high linear energy transfer (LET) radiation is an important consideration for astronauts planning interplanetary or prolonged missions. Such exposure could lead to an increased incidence of cataractogenesis. We have been studying the role of 17- beta-estradiol (E2) and age of the animal at the time of exposure in cataractogenesis induced bt high LET radiation.

Methods: : Female Sprague-Dawley were divided into four groups of 20 animals in each group. Group I consisted of 1 year old animals ovariectomized with E2 implants. Group II had 1 year old ovariectomized animals with placebo implant. Group III consisted of 1 year old ovary intact animals and Group IV consisted of 56 day old ovary intact animals. The right of each animal was irradiated with high LET radiation (2 Gy of 600 MeV 56 Fe ions). The rats were examined by slit lamp biomicroscope to measure anterior and posterior subcapsular lens opacification of both irradiated and control (contralateral ) eyes every 2-4 weeks.

Results: : The incidence of anterior and posterior subcapsular cataracts was higher in the 1 year old ovary intact when compared to 56 day old animals.

Conclusions: : Modulation by estrogen of cataractogenesis induced by high LET radiation is dependent on the age of the animal at the time of exposure to radiation.

Keywords: cataract • radiation damage: light/UV • drug toxicity/drug effects