Abstract
Abstract: :
Purpose:To assess the extent and pattern of age-related RGC loss in the C57/BL6 mouse strain. Methods:A total of 30 C57/BL6 mice of six different age groups (3,6,9,12,15 and 18 months old, 5 animals per group) were used. Retrograde labeling of RGCs was performed using a pledget soaked in 5% Fluorogold placed over both superior colliculi. Seven days later the retinas were isolated and flat-mounted onto slides. Each retina was observed on an epifluorescent microscope and a total of 250 adjacent non-overlapping frames were captured with a digital camera. The acquired images were analyzed by a software designed to rapidly count RGCs. Results:C57/BL6 mice showed a reduction of RGC count beginning at 12 months which continued as the animals aged. RGC count values were ∼27% less at 18 months than at 3 months of age (meanSD: 854432499.2 vs 6302111232, p20% loss revealed a diffuse rather than the focal pattern seen in the DBA/2Nnia glaucomatous mice. This was based on the finding that counts among hemiretinas and quadrants were not significantly different. Conclusion:C57/BL6 mice develop an age-related RGC loss that starts at 12 months and is obvious past 15 months of age. The diffuse pattern of age-related RGC loss in the C57/BL6 mice differs from the focal pattern of loss present in the DBA/2Nnia mice that develop glaucomatous changes beyond 12 months of age.
Keywords: 415 ganglion cells • 315 anatomy • 309 aging