98th Annual Meeting DOG 2000

P 4

Accumulation of deposits in Bruch’s membrane in MICE correlates with age and high-fat diet

S. Dithmar1,2, N. A. Le3, N. Sharara1, H. E. Grossniklaus1

Purpose: To examine the histologic and ultrastructural changes in Bruch’s membrane in different aged mice and the effect of elevated serum cholesterol on Bruch’s membrane.

Methods: Three groups of C57BL/6 mice were studied. Group 1 were two-months-old on a normal diet; group 2 were eight months old on a normal diet; group 3 were eight months old on a high-fat diet. The mice were sacrificed, serum lipid levels were measured, and the eyes were examined ultrastructurally.

Results: The serum cholesterol level was significantly higher in the high-fat diet mice than the controls (p=0.0001). Bruch’s membrane was thicker in group 2 than group 1 (p=0.0410) and group 3 had a thicker Bruch’s membrane than group 2 (p=0.0033). All mice in group 3 exhibited accumulation of electron-lucent particles and membrane-bounded particles in Bruch’s membrane, and one group 3 mouse developed an atheromatous-like plaque in Bruch’s membrane. Group 2 had a higher electron-lucent particle accumulation density than group 1 (p=0.0042). Group 3 did not have a higher electron-lucent particle accumulation than group 2 (p=0.17).

Conclusions: Deposits occur in murine Bruch’s membrane, and the amount and composition correlates with age and diet. These deposits resemble human basal linear deposits, which are found in human age-related maculopathy.

Departments of 1Ophthalmology and 3Lipid Research, Emory University School of Medicine, Atlanta, Ga, 2Department of Ophthalmology, University of Heidelberg, Germany, INF 400, 69120 Heidelberg
Supported by Gertrud Kusen Foundation, Germany (Di 98/99), RPB Inc., and NIH EY06360