Effects of Intravitreal Injection of an Anti-Tnf Alpha on Choroidal Neovascularization in Rats

Abstract

Purpose: : To evaluate the effects of an anti-TNF alpha antibody (infliximab) on a laser-induced choroidal neovascularization (CNV) model in rat eyes by fluorescein angiogram and immunofluorescence.

Methods: : The animals (heterozygous Zucker rats) were divided into 3 groups: controls (n=5), 100µg (n=5) and 200µg (n=5) of intravitreous injection of infliximab. Four photocoagulation burns were performed around the optic disc using the following parameters: power of 300 mW; spot size of 100 µm; exposure time of 100 ms. At the end of laser session, saline or anti-TNF alpha infliximab (100 and 200 µg) were injected intravitreously. After three weeks, fluorescein angiogram and autofluorescence exams were performed using the Heidelberg Retina Angiograph - 2 (HRA-2) (Heidelberg, Germany) to detect the area of laser-induced CNV. After clinical examination, the eyes were enucleated and immunofluorescence was performed for anti-Von Willebrand factor (for endothelial cells) directly on the eye cup (flat mount).

Results: : HRA-2 fluorescein angiogram showed clinically smaller CNV lesions in both 100 and 200 µg groups in comparison to control group. There were no signs of ischemia or hemorrhage associated with the treatment or the procedure per se. Immunofluorescence for anti-Von Willebrand factor disclosed a decreased CNV perimeter in infliximab-treated animals with both 100 µg (1414 µm; p<0.05) and 200 µg (1085 µm; p<0.05) compared with control eyes (saline injection; 3613 µm).

Conclusions: : Intravitreal infliximab seems to partially prevent the development of laser-induced CNV lesions in rats at different concentrations. Further studies are needed to ascertain its clinical potential as an antiangiogenic drug.

Keywords: choroid: neovascularization