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Modulating radiation cataractogenesis by hormonally manipulating lenticular growth kinetics
D S Holsclaw1, H Rothstein, C Medvedovsky
1Department of Ophthalmology, University of California, San Francisco.
Experimental Eye Research
|September 1, 1994
Summary
Radiation-induced cataracts require lens epithelial cell proliferation. Halting mitosis in frog lens epithelial cells prevented cataract formation, while reinstating mitosis led to cataract development, confirming mitosis
Area of Science:
- Ophthalmology
- Radiation Biology
- Cell Biology
Background:
- The lens epithelium is the primary site of injury after radiation exposure, leading to cataract development.
- Damaged lens epithelial cells are progenitors of aberrant fiber differentiation in cataracts.
- Post-radiation proliferative activity in the lens epithelium is essential for cataract formation.
Purpose of the Study:
- To investigate the role of lens epithelial cell mitosis in radiation-induced cataract development.
- To manipulate lens epithelial cell cycle activity in vivo using hormonal regulation.
- To examine the direct effect of lenticular mitosis on the cytopathomechanism of radiation cataracts.
Main Methods:
- Northern leopard frogs' lens epithelial cell cycle was manipulated via hypophysectomy (halting mitosis) and pituitary hormone administration (stimulating mitosis).
- Animals were hypophysectomized, irradiated, and received pituitary hormone replacement.
- Cataract development was assessed using slit-lamp biomicroscopy and correlated with histological mitotic index and meridional row disorganization.
Main Results:
- Irradiated frogs with halted mitosis (hypophysectomized) did not develop cataracts.
- Irradiated frogs with reinstated mitosis (hormone replacement) developed cataracts.
- Quantitative hormone administration modulated mitotic activity and cataractogenesis.
Conclusions:
- Lens epithelial cell mitosis is indispensable for the development of radiation-induced cataracts.
- Hormonal regulation of lens epithelial cell proliferation can prevent or induce cataract formation.
- Mitotic activity is a critical factor in the pathogenesis of radiation-induced lens opacities.