Abstract
Purpose: :
Vitreous extracted from rat eyes receiving penetrating ocular injury (POI) inhibits human retinal microvascular endothelial cell (HRMEC) proliferation. The purpose of the present study was to test the effect of collagen II–depleted vitreous extracts from injured and non–injured rat eyes on HRMEC proliferation, tube formation and migration. In addition, differences in the protein constituency between these two vitreous extracts were determined.
Methods: :
Two week–old Sprague–Dawley rats received POI by penetrating the temporal or nasal pole of one eye with a 26–gauge dry needle. The opposite eye served as a control. Rats were sacrificed one day later and the vitreous harvested. Rat vitreous from either injured or non–injured eyes was homogenized and collagen II was removed by sodium chloride precipitation. The potential anti–angiogenic activities of these protein samples were assessed with established cell proliferation, tube formation and migration assays. Collagen II–depleted vitreous extracts from injured and non–injured rat eyes were analyzed by matrix–assisted laser desorption ionization (MALDI) mass spectrometry.
Results: :
Collagen II–depleted vitreous extracts were tested at concentrations ranging from (1–50µg/ml). Vitreous from injured rat eyes showed a dose dependent inhibition of HRMEC proliferation ranging from 50 to 82% (p<0.001), based on comparison to vitreous from non–injured rat eyes. Vitreous from injured eyes showed an inhibition of tube formation ranging from 21 to 54% (p<0.001) and an inhibition of cell migration ranging from 3 to 46% (p<0.001), when compared to vitreous from non–injured rat eyes. Differences in protein profiles of collagen II–depleted vitreous extracts from injured and non–injured rat eyes by mass spectrometric analysis were observed and will be detailed.
Conclusions: :
The results indicate that collagen II–depleted vitreous extracts from injured rat eyes significantly decreased HRMEC proliferation, tube formation and migration when compared to vitreous extracted from non–injured eyes. We believe these anti–angiogenic activities are related to the differences in protein constituency determined by mass spectrometric analysis.
Keywords: neovascularization • protein purification and characterization • vitreous