Optic nerve head width and retinal nerve fiber layer changes are proper indexes for validating the successful induction of experimental anterior ischemic optic neuropathy. (April 2019)

• Record Type: Journal Article
• Authors: Kapupara, Kishan; Huang, Tzu-Lun; Wen, Yao-Tseng; Huang, Shun-Ping; Tsai, Rong-Kung
• Is Part Of: Experimental eye research. Volume 181(2019)
• Page Start: 105
• Page End: 111
• Publication Date: 2019-04
• Subjects: Anterior ischemic optic neuropathy in rats (rAION) -- Optic nerve head (ONH) -- Retina nerve fiber layer (RNFL) -- Optical coherence tomography (OCT) -- Retinal ganglion cells (RGCs); Ophthalmology -- Periodicals; Eye -- Periodicals; Œil -- Périodiques; Ophthalmology; Periodicals; Electronic journals; 612.8405
• DOI: 10.1016/j.exer.2018.12.007
• Languages: English
• ISSNs: 0014-4835

Abstract

Abstract: Reproducible skills are essential for successful induction of a rat model of anterior ischemic optic neuropathy (rAION). We established an in vivo validation index by measuring the natural course of optic nerve head (ONH) width and retinal nerve fiber layer (RNFL) thickness in the rAION model using optical coherence tomography (OCT). The rAION model was induced by photodynamic operations. We measured the ONH width, RNFL, Inner Plexiform layer (IPL) and Ganglion cell complex (GCC) thickness in the acute stage (<3 days), subacute stage (day-7 to day-14) and later stage (day-14 to day-28) post-infarct by OCT. Retinal layers were measured by hematoxylin and eosin stain (HE) to confirm the OCT findings. The RGCs survival rate was determined by retrograde Fluoro-gold labeling, and the visual function was assessed with flash visual-evoked potentials (FVEPs) 4 weeks post-infarct. We observed significant thinning in GCC, IPL, and RNFL at day-14 and day-28 but only RNFL showed significant thinning between day-14 and day-28. The ONH showed significant swelling in the acute stage which correlated at a greater extent with RNFL than GCC and IPL. Further RNFL correlated at a greater extent at with GCC than IPL. HE-stained retina cross sections also showed IPL and RNFL thinning, which further confirmed our OCT findings. The RGC density and P1-N2 amplitude were significantly reduced in rAION. Our data suggest that Swelling, reduction of swelling, and atrophy of RNFL in acute, sub-acute, and later stage, respectively and ONH swelling in the acute stage are essential events for confirming the successful induction of rAION. Highlights: Retina nerve fiber layer (RNFL) and optic nerve head (ONH) edema occur from day-1 to day-3 post-infarct. ONH edema correlates with RNFL at a greater extent than ganglion cell complex (GCC) and inner plexiform layer (IPL). RNFL thinning starts from day-14 due to RGC loss. RNFL and ONH changes act as a reliable assessment index for the successful generation of a rat model of anterior ischemic optic neuropathy.