Abstract
Abstract: :
Purpose: Previous studies have shown that increased transscleral permeability following exposure to certain prostaglandins is associated with increased matrix metalloproteinase (MMP) production. The present study was undertaken to determine whether exposure of intact eyes to MMPs enhances delivery of extraocular macromolecules to the retina. Methods: Freshly enucleated mouse eyes were incubated with 1–µg/ml each of human MMP–1, MMP–2, and MMP–14 for 4 hours at 37°C. The eyes then were incubated with 2.5–µg /ml 70 kDa dextran–tetramethylrhodamine–lysine for 16 or 32 minutes at 37°C, rinsed briefly, fixed in buffered 4% paraformaldehyde, and frozen sections were prepared. Controls included eyes that were incubated without MMPs and then incubated with or without dextran for 16 or 32 minutes. After the identity of the sections was masked, the intensity of fluorescence in anterior, middle, and posterior regions of the outer retina and inner retina was scored using a 7–point grading scheme (1: dim as in the tissues of non–incubated control eyes to 7: bright as in the sclera of incubated eyes). Statistical analysis considered all regions together as well as separately. Results: The structural organization of the retina and other ocular tissues was maintained in all experimental conditions. Retina Scores After 4–hour MMP Treatment: All Regions Considered Together
Scores of Each Retina Region Considered Separately: 32–Minute Dextran Probe Conclusions: Incubation of mouse eyes with MMPs 1, 2, and 14 enhances 70 kDa dextran access to the retina. This effect is more pronounced in the outer retina and greater towards the posterior region of the eye.
Keywords: pharmacology • extracellular matrix • retina