Role of Vascular Endothelial Growth Factor in the Breakdown of the Blood-Aqueous Barrier After Retinal Laser Photocoagulation in Pigmented Rabbits

Abstract

Retinal laser photocoagulation is used to treat a variety of retinal diseases. Breakdown of the blood-aqueous barrier has been noted after retinal laser photocoagulation. The effect of vascular endothelial growth factor (VEGF) on the function of the blood-aqueous barrier after retinal laser photocoagulation remains undetermined. The current study was designed to evaluate the relationship between intraocular levels of VEGF and breakdown of the blood-aqueous barrier after retinal laser photocoagulation in rabbits. Pigmented rabbits were treated with retinal laser photocoagulation in one eye; the other served as control. Laser flare photometry was carried out on post-treatment days 1, 3, 7, and 14. Animals were sacrificed at the time period just mentioned postlaser, the eyes were removed, and samples of vitreous and aqueous humor were collected. Intraocular VEGF levels were measured by using an immunoassay. An intravitreal injection of VEGF was administered, and the aqueous flare intensity and VEGF levels in the aqueous and vitreous humor were measured at the time periods just mentioned. A significant increase in the aqueous flare intensity after retinal laser photocoagulation was noticed on postoperative day 1, with the values returning to baseline levels on day 14. The VEGF levels in the vitreous of the lasered eyes were significantly increased on day 1 compared with the nonlasered control eyes. The VEGF levels in the aqueous humor of the lasered eyes were also significantly increased on day 1 compared with the control eyes. An intravitreal injection of VEGF induced a significant increase in the aqueous flare intensity and VEGF levels in the aqueous and vitreous humor. The current results suggested that retinal laser photocoagulation can produce a breakdown of the blood-aqueous barrier. VEGF may play a role in the blood-aqueous barrier dysfunction after retinal laser photocoagulation.