Abstract
Purpose: :
To determine the efficacy of neuroprotectin D1 (NPD1; RX-20001), a neuroprotective derivative of docosahexaenoic acid (IOVS 48:4866;2007), on choroidal endothelial cell ramification in laser-induced choroidal neovascularization (CNV).
Methods: :
CNV was induced using an ophthalmic laser attached to a slit lamp. Three 50 µm diameter lesions (Laser protocol: Energy, 150 mW; Duration, 100 mS; Diameter, 50 µm) were made on both retinas of anesthetized mice. NPD1 was administered i.p. once daily at a dose of 114µg/kg (200µL injection volume) at times 0 (just prior to laser treatment) and +1, +3, +5, and +7 days after laser treatment. Saline-injected animals served as controls, following the same schedule. FITC-labeling and leakage imaging was obtained at day 7 and day 14. Retinas were collected and choroidal flatmounts produced for confocal imaging and analysis of lesion sites. Immunohistochemistry was performed on these flatmounts to selectively label actin, nuclei, and endothelial cells. Images were analyzed (ImageJ) to obtain pixel counts of the labeled endothelial cells in each slice of the lesion. Summation produced an estimate of the total endothelial cell volume per lesion site.
Results: :
In control mice (n=7) at day 7, the area of endothelial cell growth had an average pixel count of 261,181 pixels, while NPD1-treated mice (n=7) at day 7 had an average pixel count of 138,429 pixels (53% decrease). At 14 days control mice had an average pixel count of 205,897 pixels, while 14 day NPD1-treated mice showed a further marked reduction in endothelial cell count with an average pixel count of 69,463 pixels. This amounted to a 66% decrease compared to controls at day 14 and was highly significant.
Conclusions: :
These results indicate that there is a decreased angiogenesis after laser-induced CNV in NPD1-treated mice, suggesting that this neuroprotective mediator may have a therapeutic role in vascular-associated retinal diseases such as AMD.
Keywords: neuroprotection • choroid: neovascularization • age-related macular degeneration