Abstract
Purpose :
To evaluate the changes in the retinal structure and retinal vasculature in type-1 diabetic mice (C57BL/6-Ins2Akita/J ) over time.
Methods :
Fluorescein angiography (FA), Indocyanine green angiography (ICGA) and OCT imaging was performed on Akita mice at 3 months and 6 months of age. The confocal scanning laser ophthalmoscopy (cSLO) images were analyzed for FA and ICGA. OCT images were evaluated for thickness measurement of distinct layers of the retina. A total of 25 (male) animals were used in the study. FA was performed after IP injection of Na- fluorescein, and images were collected at ~three mins and ~six mins for early and late phase of dye circulation. ICG was administered via tail vein. Statistical comparison were made using non-parametric two tailed t-test with significance at P<0.05.
Results :
Using ImageJ, a simple thresholding protocol was developed, which uses IsoData algorithm, and fixed lower and upper threshold values for all the FA and ICG images. Both FA and ICGA showed significantly increased retinal vasculature leakage (92% increase in FA and 101.9 % increase in ICGA) in 6-month old Akita mice compared with age matched WT (Fig. 1). OCT based total retinal thickness was significantly reduced in Akita mice at both three (2.8%) and six (2.5%) months of age. The middle retinal layer thicknesses, OPL and ONL were significantly different in mice in the 6-month age group (Fig.2). However, at three months, only the OPL layer had thinning in the outer and middle retinal region (Fig. 2). No observable changes were observed in the outer retinal layers (IS/OS and RPE).
Conclusions :
Aging diabetic mice exhibit clear imaging biomarkers such as retinal fluid leakage and inner retinal layer degeneration.
This is a 2021 ARVO Annual Meeting abstract.