A Novel Animal Model of Optic Nerve Transection with Preservation of Retinal Perfusion
Vahe Fahradyan, MD, Eliana Duraes, MD, Cagri Cakmakoglu, MD, Bahar Bassiri Gharb, MD, PhD , Antonio Rampazzo, MD, PhD, Maria Madajka, PhD, Grzegorz Kwiecien, MD, Addison Barnett, BS, Chris Link, Michaela Edmond, Brent Allen Bell, Alex Yuan, MD,PhD, Neal Peachey, PhD, Francis Papay, MD
Cleveland Clinic Foundation
Presenter: Vahe Fahradyan
Vahe Fahradyan was involved in all steps of this study.
Director Name: Bahar Bassiri Gharb
Author Category: Fellow Plastic Surgery
Presentation Category: Basic Science Research
Abstract Category: Craniomaxillofacial
PURPOSE: Poor optic nerve regeneration still remains one of the major challenges preventing successful eye transplantation. The purpose of this study was to establish an optic nerve transection model that would allow evaluation of axonal regeneration of retinal ganglion cells (RGC).
METHODS: Lewis and Long Evans rats were dissected, optic nerves were exposed and transected to create a clean-cut injury. Incision along the superior orbital rim and extending to the lateral temporal area with partial excision of temporalis muscle provided adequate exposure of the optic nerve. The levator palpebrae superioris and superior rectus muscles were transected, the Harderian and lacrimal glands were retracted and preserved. A superior-temporal minimal longitudinal transection of dura mater provided enough space for optic nerve transection and allowed to retain integrity of the ophthalmic artery.
Spectral domain optical coherence tomography (SD-OCT), electroretinography (ERG) and confocal scanning laser ophthalmoscopy (cSLO) were used to evaluate morphology, electrical activity and vascularity of the retina.
RESULTS: SD-OCT detected progressive atrophy of nerve fiber layer of the retina over the post-operative 12 week follow up period. SLO with fluorescein and indocyanine green angiography revealed intact retinal and choroidal vasculature respectively. Positive peaks were detected on the ERGs of operated eyes in response to pattern stimulation. However, the amplitudes of the waves were decreased in operated eyes compared to non-operated eyes.
CONCLUSION: We were able to maintain the integrity of the ophthalmic artery and retinal perfusion and develop optic nerve transaction model, which is optimal for the studies evaluating optic nerve regeneration.
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