EFFECT OF AET ON $gamma$-RAY CATARACTS
Although 2-aminoethylisothiouronium bromide hydrobromide (AET) is one of the most potent radioprotective agents, it failed in previous studies to protect the lens against ionizing radiation as manifested by the development of radiation cataracts in surviving mice. Revaluation of this problem was undertaken using the rat. Cell production was also studied by intraocular injections of H/sup 3/- labeled thymidine which is incorporated into cellular DNA during the premitotic doubling stage of cell division. Thus, at various intervals following irradiation, it was possible to determine the effects of radiation on the proliferation rate of the lens epithelium and the influence of pretreatment with AET. Rats were given a 200 mg/kg intraperitoneal injection of AET 15 min prior to irradiation and placed in molds behind a 12-in. lead shield so that only one eye was irradiated. A second injection of 100 mg/kg of AET was given immediately before irradiation. The animals were given a Co/sup 60/ r dose at the rate of 40 r/min to 2400 r. AET pretreatment of irradiated eyes was shown to give marked protection against early radioinduced changes in the lens, the structure of the fibers, and the eye lid. AET radioprotective action was still evident at eight months. Clinically and histologically the AET-irradiated lenses showed few signs of radiation damage during the first 14 days following radiation. Cell death and changes in the palisade structure of cells appeared minimal in the AET-irradiated lenses compared to marked changes seen in the irradiated-only lenses at 4 months. Slight signs of lens epithelial cell death were seen in the AET-irradiated animals sacrificed at 4-8 months, whereas in the irradiated-only animals the structure of the lens was almost unrecognizable at this time. AET pretreatment alone had no noticeable effect on the structure of the lens. Clinical cataract was absent or minor in the AET-irradiated eye in 8 months while in the irradiated- only eye in the same animal the cataract was complete. In the AET-irradiated eyes there was an absence of epilation of the lids after 8 months. (TCO)
- Research Organization:
- Univ. of Arkansas, Little Rock
- NSA Number:
- NSA-17-033637
- OSTI ID:
- 4654875
- Journal Information:
- Arch. Intern. Pharmacodyn., Journal Name: Arch. Intern. Pharmacodyn. Vol. Vol: 142
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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