Ovariectomy worsens visual function after mild optic nerve crush in rodents

• Type of Material: Article
• Authors: Rachael Allen, Emory University; Amber Douglass, Atlanta VA Healthcare System; Harrison Vo, Atlanta VA Healthcare System; Andrew Feola, Emory University
• Language: English
• Date: 2021-01-01
• Publisher: Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: Published by Elsevier Ltd.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.exer.2020.108333
• Title of Journal or Parent Work: Experimental Eye Research
• Volume: 202
• Start Page: 108333
• End Page: 108333
• Grant/Funding Information: This work was supported by the Department of Veterans Affairs Rehab R&D Service Career Development Awards to AJF (CDA-2; RX002342) and RSA (CDA-2; RX002928) and the NEI Core Grant P30EY006360.
• Keywords: Rats, Long-Evans; Glaucoma; Visual Acuity; Menopause; Animals; Electroretinography; Optic Nerve Injuries; Female; Retina; Estrogen; Nerve Crush; Nerve Fibers; Tomography, Optical Coherence; Optic nerve crush; Disease Models, Animal; Retinal Ganglion Cells; Rats; Ovariectomy; Visual function; Vision Disorders

Abstract

Glaucoma is the leading cause of irreversible blindness worldwide, and women represent roughly 60% of the affected population. Early menopause and estrogen signaling defects are risk factors for glaucoma. Recently, we found that surgical menopause exacerbated visual dysfunction in an ocular hypertension model of glaucoma. Here, we investigated if surgical menopause exacerbated visual dysfunction in a model of direct retinal ganglion cell (RGC) damage via optic nerve crush (ONC). Female Long Evans rats (n = 12) underwent ovariectomy (OVX) to induce surgical menopause or Sham surgery. Eight weeks post-surgery, baseline visual function was assessed via optomotor response. Afterwards, rats underwent monocular ONC. Visual function was assessed at 4, 8, and 12 weeks post-ONC. At 12 weeks, retinal function via electroretinography and retinal nerve fiber layer (RNFL) thickness via optical coherence tomography were measured. Visual acuity was reduced after ONC (p < 0.001), with surgical menopausal animals having 31.7% lower visual acuity than Sham animals at 12 weeks (p = 0.01). RNFL thinning (p < 0.0001) and decreased RGC function (p = 0.0016) occurred at 12 weeks in ONC groups. Surgical menopause worsens visual acuity after direct RGC damage using an ONC model. This demonstrates that surgical menopause plays a role in visual function after injury.