Evaluation of Neopterin Levels in an Endotoxin-Induced Experimental Uveitis Model

Abstract

Background: In this study, NP levels of intraocular fluids and serum were analyzed in the endotoxin-induced uveitis model. Methods: Intravitreal injection of 0.05 ml E. Coli lipopolysaccharide (IVT LPS) has been performed into the right eyes of 14 rabbits. Animals were divided into two groups. Group 1 (n = 7) sacrificed 24 hours after the intravitreal injection, and group 2 (n = 7) 72 hours after the intravitreal injection. Aqueous fluid, vitreous and serum samples were drawn at the time of sacrifice; histopathological changes were also examined. Results: Significantly elevated aqueous and vitreous NP levels were observed in IVT LPS injected eyes. In IVT LPS injected eyes, aqueous NP levels showed a significant decrease in 72 hours (p < 0.05), whereas vitreous NP concentrations significantly increased in 72 hours (p < 0.05). Both aqueous and vitreous protein concentrations were significantly higher in IVT LPS injected eyes. Histopathologic evaluation revealed that, in the first 24 hours, inflammation was significant in choroid and ciliary body. Retinal histopathological changes were observed mainly at 72 hours. Conclusions: This study demonstrates that neopterin levels correlate with early intraocular inflammatory response in an endotoxin-induced uveitis model.