PURPOSE: To develop a scoring system for the mouse model of oxygen induced retinopathy based on examining retinal whole mount preparations.

METHODS: The mouse model of oxygen induced retinopathy utilizing fluorescein conjugated dextran angiography of retinal vasculature was employed. Specific parameters that were scored included blood vessel growth, blood vessel tuft formation, extraretinal neovascularization, degree of central vasoconstriction, retinal hemorrhage, and tortuosity of vessels. In addition, quantification of neovascular nuclei was performed on PAS stained retinal sections.

RESULTS: Animals that were exposed to hyperoxia for five days had an average retinopathy score of 8.4 ±1.3 versus control animals that had an average retinopathy score of 1.5±0.8 (p <0.0001). Subscores for blood vessel growth, blood vessel tortuosity, extraretinal neovascularization, central vasoconstriction and hemorrhage/plus disease were all statistically significantly different between control and hyperoxic treated animals. In addition, quantification of neovascular nuclei showed a significant increase in the number of nuclei in hyperoxic treated animals.

CONCLUSIONS: This scoring system provides a retinal whole mount method of quantification of oxygen induced retinal neovascularization based on clinical features seen with Retinopathy of Prematurity. This system can be applied to assess anti-angiogenic agents in vasoproliferative retinopathies in an animal model system. Funded by National Eye Institute EY00330.