Abstract
Purpose::
We propose to use zebrafish as an animal model to identify drugs that inhibit Choroidal Neovascularization (CNV). The architecture of the zebrafish eye is strikingly similar to the human eye. In recent research, using a low concentration of CoCl2 (0.1mg/ml), we induced hypoxia in the zebrafish eye and observed abnormal vessel growth specifically in the choroidal region, similar to the CNV phenotype present in humans.
Methods::
Under normal conditions, zebrafish do not have vessels in the retina. To induce abnormal CNV, we incubated day 1 zebrafish with 0.1 mg/ml of CoCl2 for 4 days. Next, we detected abnormal vessel growth in the choroidal and retinal layers of the zebrafish eye using Phy-V (Phylonix, Cambridge, MA), a monoclonal antibody (mAb) that specifically stains activated endothelial cells in nascent vessels. To further characterize our CNV model and to investigate whether abnormal vessels penetrate the retina, we used immunohistochemistry to stain new vessels in the eye. Using RT-PCR and in situ hybridization, we then confirmed that the mechanism of abnormal neovascularization was related to CoCl2 induction of HIF-1 and VEGF. We developed an ELISA assay "eZ-CNVTM" to quantitate level of angiogenesis and we used this assay format to assess effects of three antiangiogenic compounds: Celebrex, Genistein and SU5416.
Results::
After treatment with CoCl2, zebrafish exhibited abnormal vessels in the retina, edema, and photoreceptor degeneration, similar to the phenotypes presented in human CNV. Results of RT-PCR and in situ hybridization demonstrate that the mechanism of abnormal neovascularization was related to CoCl2 induction of HIF-1 and VEGF, underscoring the similarity of CNV mechanisms in zebrafish and mammals. Celebrex, Genistein and SU5416 all inhibited CNV in a dose-dependant manner.
Conclusions::
The zebrafish CNV model and the eZ-CNVTM ELISA assay can be used to identify potential antiangiogenic drug candidates.
Keywords: choroid: neovascularization • drug toxicity/drug effects • retinal neovascularization