Abstract
Purpose: :
Vitreous protein isolated from rats receiving penetrating ocular injury (POI; dry-needle puncture of the globe at the temporal ora) inhibits human retinal microvascular endothelial cell (HRMEC) proliferation and migration, as well as oxygen-induced retinopathy (OIR), in a dose-dependent manner. The purpose of the present study was to determine whether the stage of retinal development or predisposition to neovascular disease influences the production of angiostatic proteins isolated from the vitreous after POI.
Methods: :
Adult Sprague Dawley (SD) rats, 14-day-old (P14) SD rats raised in room air (RA), or P14 SD rats exposed to an oxygen-treatment protocol to induce OIR received POI in the left eye. The right eye served as a non-POI control. Rats were sacrificed one day later and the vitreous was harvested. Vitreous from POI and non-POI eyes was homogenized and fractioned by centrifugation (100,000 x g) to remove insoluble material. The angiostatic activity of the supernatant was assessed in HRMEC with BrdU ELISA. The supernatant was fractionated with a cation-exchange resin, and the anti-proliferative activity of each fraction was similarly assessed in HRMEC. Fractions with significant angiostatic activity were further assessed for cytotoxicity using a modified Live/Dead® Kit.
Results: :
POI vitreous protein extracts from all three treatment regimens showed significantly increased angiostatic activity compared to vitreous protein from non-POI eyes (p < 0.05). Extracts from POI eyes of adult SD, P14 RA and P14 OIR rats showed no significant difference in angiostatic activity. Seven of 25 vitreous protein fractions from POI eyes inhibited cell proliferation without cytotoxicity (p < 0.05).
Conclusions: :
Vitreous protein isolated from rats receiving POI showed angiostatic activity regardless of age or OIR disposition. Current studies focus on the purification, identification and characterization of angiostatic vitreous proteins that are non-toxic. These proteins could potentially serve as novel chemotherapeutic modalities for the treatment of neovascular retinopathies.
Keywords: retina • vitreous • neovascularization