Abstract
Purpose :
Age-related alterations in vitreous collagen fiber structure underlie posterior vitreous detachment and retinal detachment, but research into vitreous aging has been limited to the use of large animal models, which age slowly. In this ex vivo ocular imaging study, we tested the hypothesis that aged wild-type C57BL/6J mice would demonstrate decreased fiber density and greater variation in fiber distribution, mimicking age-related alterations in human vitreous.
Methods :
We used confocal reflectance microscopy to image mid-vitreous collagen fiber structure at the superior equator in young (5- to 6-week-old, n=8; 5 males, 3 females) compared to middle-aged (6- to 7-month-old, n=10; 5 males, 5 females) wild-type C57BL/6J mice (Figure 1A, B). We applied the Fiji ridge detection plug-in to quantify the number of fibers in each two-dimensional image. To quantify the variation in fiber distribution in a manner independent of the overall density, we divided each image into 16 tiles, quantified the number of fibers in each tile, and calculated the ratio of fibers in the 8 highest density tiles compared to the 8 lowest density tiles.
Results :
Overall fiber density in the young mice was 447 ± 175 fibers/image (mean ± SD), and overall fiber density in the middle-aged mice was 171 ± 132 fibers/image, which was significantly lower (p = 0.002, unpaired t-test) (Figure 1C). Variation in fiber distribution, as measured by the ratio of high/low density tiles, was significantly higher in the middle-aged mice (3.58 ± 1.38) compared to the young mice (1.80 ± 0.34) (p = 0.003, unpaired t-test) (Figure 1D).
Conclusions :
Middle-aged wild-type C57BL/6J mice demonstrate decreased vitreous collagen fiber density and greater variation in fiber distribution compared to young mice. These findings suggest that mice can be used to model age-related changes in vitreous structure that lead to vision loss and disease in humans.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.