Neovascular Models of the Rabbit Eye Induced By Hydroperoxide

Abstract

The eye is rich in oxidizable substrates which often increase in ocular disease. In vivo rabbit models described in this chapter provide valuable clinical and biomolecular data, whereas in vitro models are used to define physiological observations such as endothelial cell proliferation, migration and vascular tube ­formation. Antioxidant supplementation significantly inhibits these phenomena and is facilitated when multiple antioxidants are given simultaneously. The 13-­isomer of linoleic acid hydroperoxide (HpODE) stimulates neovascularization when injected into the corneal stroma, the vitreous, or subretinal to create appropriate animal ­models. During this process, nuclear factors, metalloproteinase and angiogenic cytokines are ­upregulated within 3–6 h to initiate the neovascular response. Fluorescein angiography­ provides direct visualization of new vessel growth. A variety of oxidative stress biomarkers can be measured in plasma, ocular homogenates and tissue culture cells, or media. Histology confirms location of injected HpODE, presence or absence of an inflammatory response, hemorrhage and illustrate features that resemble human disease. New vessels grow at the rate of 0.3 mm/day and plateau at 3–4 weeks as the HpODE stimulus is metabolized. Repeat injections result in an accelerated growth rate. Vessel length in diabetic rabbits is double that observed in normal animals. In contrast to surgical or laser-induced neovascularization ­models, the HpODE model uses a natural substrate and is considered a ­non-traumatic ­procedure. All models are valuable to validate antioxidant intervention studies in clinical trials.