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Sodium Iodate Produces a Strain-Dependent Retinal Oxidative Stress Response Measured In Vivo Using QUEST MRI.
Bruce A Berkowitz1, Robert H Podolsky2, Jacob Lenning3
1Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan, United States 2Department of Ophthalmology, Wayne State University School of Medicine, Detroit, Michigan, United States.
Researchers identified noninvasive biomarkers to measure oxidative stress in retinal layers of mice. This helps understand genetic vulnerabilities in retinal degeneration, paving the way for new diagnostic tools.
Area of Science:
- Ophthalmology
- Biomedical Engineering
- Oxidative Stress Research
Background:
- Oxidative stress plays a critical role in retinal degeneration.
- Identifying biomarkers for oxidative stress severity in retinal layers is crucial for understanding disease pathogenesis.
- Genetic factors influence susceptibility to oxidative stress-induced retinal damage.
Purpose of the Study:
- To identify noninvasive biomarkers for measuring oxidative stress severity in specific retinal layers.
- To compare oxidative stress levels in sodium iodate (SI)-atrophy vulnerable (C57BL/6 [B6]) and SI-atrophy resistant (129S6/SvEvTac [S6]) mice.
- To evaluate the efficacy of antioxidants in mitigating SI-induced retinal changes.
Main Methods:
- Superoxide production was measured ex vivo in whole retinas.
- In vivo excessive free radical production was assessed using QUEnch-assiSTed MRI (QUEST MRI) by measuring layer-specific 1/T1 values before and after α-lipoic acid (ALA) administration.
- Visual performance (optokinetic tracking) and retinal layer dimensions (OCT, MRI) were evaluated in SI-treated mice ± antioxidants.
Main Results:
- SI-treated B6 mice exhibited significantly higher retinal superoxide production compared to SI-treated S6 mice.
- QUEST MRI revealed that ALA administration reduced 1/T1 values in more retinal layers in SI-treated B6 mice than in SI-treated S6 mice.
- Antioxidants improved contrast sensitivity in both SI-treated strains, but did not alter visual acuity; retinal thicknesses remained normal.
Conclusions:
- QUEST MRI is a unique tool for quantifying excessive free radical production within retinal layers in vivo.
- Understanding the mechanisms of genetic vulnerability to oxidative stress is key to unraveling the pathogenesis of retinal degeneration.
- These findings contribute to the development of noninvasive biomarkers for retinal oxidative stress and potential therapeutic strategies.
