Related Experiment Video
Updated: Jul 10, 2026
Studying Chronic Exposure of Mice to Ultraviolet B Radiation
Published on: August 19, 2025
Ultraviolet radiation-induced corneal degeneration in 129 mice
Kimberly M Newkirk1, Heather L Chandler, Allison E Parent
1Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio 43210, USA. kmnewkirk@mail.ag.utk.edu
Abstract:
Ultraviolet radiation (UVR) is a risk factor for the development of ocular disease in humans, including acute photokeratitis, chronic corneal spheroidal degeneration, and cataract formation. This report describes the ocular lesions seen in 21 mice chronically exposed to UVR as part of a skin carcinogenicity study. All globes were affected to varying degrees. The primary lesion, not previously reported in UVR-exposed mice, was marked loss of keratocytes relative to age-matched controls. Secondary lesions included corneal stromal thinning, keratoconus, corneal vascularization and fibrosis, keratitis, globe rupture, and phthisis bulbi. In addition, more than 90% of UVR-exposed and unexposed lenses had evidence of cataract formation; this is the first report of the occurrence of spontaneous cataracts in 129 mice. In a subsequent study, apoptotic cells were identified histologically and by cleaved caspase 3 immunoreactivity in the corneal epithelium and, less commonly, in the corneal stroma after acute UVR exposure. Based on this finding, we propose that the loss of keratocytes observed in the chronic study was due to UVR-induced apoptosis.
Insights
Ultraviolet radiation (UVR) causes significant ocular damage in mice, including keratocyte loss and cataracts. UVR-induced apoptosis is proposed as the mechanism behind these observed corneal and lens lesions.
Area of Science:
- Ophthalmology
- Photobiology
- Toxicology
Background:
- Ultraviolet radiation (UVR) is a known risk factor for human ocular diseases.
- Previous studies have not extensively detailed UVR-induced ocular lesions in mice.
Purpose of the Study:
- To investigate and characterize ocular lesions in mice chronically exposed to UVR.
- To identify the cellular mechanisms responsible for UVR-induced ocular damage.
Main Methods:
- Chronic UVR exposure in mice as part of a skin carcinogenicity study.
- Histological examination of globes to identify ocular lesions.
- Immunohistochemistry for cleaved caspase 3 to detect apoptosis.
Main Results:
- Chronic UVR exposure led to significant ocular lesions in all affected globes.
- A primary lesion of marked keratocyte loss was observed, not previously reported in UVR-exposed mice.
- Secondary lesions included corneal thinning, keratoconus, vascularization, fibrosis, keratitis, globe rupture, and phthisis bulbi.
- Spontaneous cataracts were prevalent in both UVR-exposed and unexposed mice, with a notable occurrence in 129 mice.
- Acute UVR exposure induced apoptotic cells in the corneal epithelium and stroma.
Conclusions:
- UVR causes a spectrum of severe ocular lesions in mice.
- UVR-induced apoptosis is the likely mechanism for keratocyte loss in the cornea.
- The high incidence of spontaneous cataracts in 129 mice warrants further investigation.
