Detection of Retinal Fibrosis in a Rabbit Model of Penetrating Eye Injury

INTRODUCTION: To establish a rabbit model of posterior penetrating eye injury as a platform to test potential therapeutics. MATERIALS AND METHODS: Anesthetized rabbits received posterior penetrating eye injury in one eye, whereas contralateral eyes were maintained as uninjured controls. Rabbits were randomized into two experimental groups. Group A was euthanized on Day 14 postinjury to determine retinal fibrosis at an early phase of disease progression. Group B was euthanized on Day 28 postinjury to examine retinal fibrosis at a late phase of disease progression. We examined animals on postinjury Days 7, 14, 21, and 28 with indirect ophthalmoscope and fundus photography. After euthanasia, eyes were processed for histology and immunofluorescence labeling of fibrotic proteins alpha-smooth muscle actin and collagen I. RESULTS: Early fibrosis was detected by Day 14, as indicated by indirect ophthalmoscopy and fundus imaging. Fibrotic membranes were visible at sites of injury. Immunofluorescence analysis detected alpha-smooth muscle actin and collagen I within the fibrotic membranes. CONCLUSIONS: These data show that ocular fibrosis can be detected within 14 days after initial injury, with more severe fibrosis detected at 28 days postinjury. These results will be used to determine the optimal time points for later studies designed to test treatment strategies.