Morphometric Analysis of Retinal Ganglion Cell Axons in Normal and Glaucomatous Brown Norway Rats Optic Nerves

• DOI: 10.1167/tvst.12.3.8
• Publication Date: 2023-03-14T15:31:07Z
• Authors: Vidisha Goyal; A. Thomas Read; Dillon M. Brown; Luke Brawer; Kaitlyn Bateh; Bailey G. Hannon; Andrew J. Feola; C. Ross Ethier
• Keywords: Axoplasmic transport

Purpose: A reference atlas of optic nerve (ON) retinal ganglion cell (RGC) axons could facilitate studies neuro-ophthalmic diseases by detecting subtle RGC axonal changes. Here we construct an for normotensive eyes in Brown Norway rats, widely used glaucoma research, and also develop/evaluate several novel metrics damage hypertensive eyes. Methods: Light micrographs entire ON cross-sections from were processed through a deep learning-based algorithm, AxoNet2.0, to determine morphological properties semiquantitatively scored using the Morrison grading scale (MGS) provide score independent AxoNet2.0 outcomes. To atlases, ONs conformally mapped onto “template,” morphometric data was computed each region. We developed based on myelin morphometry. Results: In eyes, average axon density ∼0.3 axons/µm2 (i.e., ∼80,000 ON). measured axoplasm diameter, eccentricity, cross-sectional area, g-ratio thickness. Most parameters exhibited wide range coefficients variation (CoV); however, thickness CoV only ∼2% increased correlated strongly with MGS (P < 0.0001). Conclusions: present first comprehensive normative rat suggest objective, repeatable Translational Relevance: These tools can evaluate regional changes RGCs overall levels rats.