Age-related Ocular Changes in C57BL/6J mice from P30 – P930

Abstract

Purpose : Aging is a major risk factor for various ocular ailments, such as age-related macular degeneration, glaucoma, and diabetic retinopathy. The purpose of this study was to assess natural changes to ocular morphology and function that occur during aging in C57BL/6J mice.

Methods : Four different age groups of C57BL/6J mice were used in this study. Group 1 were less than 0.5 years (P30 – P180; N = 3 - 13), Group 2 ranged from 1.0 – 1.5 years (P365 – P544; N = 3 -12), Group 3 ranged from 1.5 – 2.0 years (P545 – P730; N = 3 - 9), and Group 4 were 2.0+ years (P731+; N = 3 - 8). These mice were assessed for visual function using full-field electroretinograms (ERGs), in vivo retinal imaging through SD-OCT allowed for quantification of various retinal layer thickness, and blue autofluorescence imaging was conducted using Spectralis HRA+OCT. Post-mortem tissue was collected for eye weight measurements, H&E staining, and nuclei counting of the photoreceptor layer.

Results : For visual function, there was a significant decrease in amplitudes between Group 1 and the older groups for Scotopic and Photopic A and B waves; however, there were no significant differences between Groups 2, 3, and 4 (one-way ANOVA). Total retinal thickness, as measured through SD-OCT quantification, showed significant decreases between Groups 1 and 2, 2 and 3, 1 and 3, and 1 and 4. Photoreceptor layer thickness statistically decreased between Groups 1 and 2, 1 and 3, 1 and 4, and 2 and 4 (one-way ANOVA). Eye weights significantly increased across all groups as age increased; however, when adjusted for body weight, significantly differences were only seen between Group 3 and 4 (one-way ANOVA). H&E stained section showed significant differences in nuclei counts of the photoreceptor layer between the youngest group (Group 1) and the oldest group (Group 4) (two-way ANOVA).

Conclusions : Overall, we observed significant decreases in visual function and retinal thickness across all the groups as age increased. These results align with previous research showing that even healthy individuals have ocular changes due to aging. As the average lifespan continues to increase with advances in modern medicine, the development of strategies that extend good vision health will rely on developing animal models to better understand the natural ocular changes that occur due to aging.

This is a 2020 ARVO Annual Meeting abstract.