Abstract
Purpose: :
Nutrients and oxygen necessary for early retinal development are provided by a vascular network of the vitreous called the hyaloid system. As the hyaloid system regresses, the retinal vasculature develops radially from the optic disk. Opticin is a vitreous glycoprotein that has anti-angiogenic properties. In this study, we investigate if a lack of opticin perturbs hyaloid regression and retinal vascular development.
Methods: :
Initially, immunohistochemistry was performed on 5 µm eye sections from wild-type and Optc-/- mice at P4, P7 and P17 using an anti-mouse opticin antibody. Subsequently, the hyaloid vessels and retinal vasculature were fluorescently labelled with isolectin B4 in wild-type and Optc-/- eye cups and retinal flat-mounts prepared at P4, P7, P17 and P35 to observe vascular development.
Results: :
Opticin was localized to the non-pigmented ciliary epithelium, vitreous, hyaloid vasculature and trabecular meshwork. Fluorescent microscopy revealed a more extensive hyaloid vascularization in the Optc-/- mice at P4 and P7 compared to their wild-type counterparts. While the hyaloid network had totally regressed in the wild-type animals at P35, residual vessels were observed in a proportion of the Optc-/- mice. Analyses of retinal flat-mounts at P4 and P7 revealed a delay in retinal vascularization in Optc-/- compared to wild-type mice; however, no differences were observed in the vascular pattern by P17.
Conclusions: :
Opticin is involved in hyaloid regression and indirectly influences the rate of retinal vascularization.
Keywords: vitreous • extracellular matrix • glycoconjugates/glycoproteins