Pigmented and albino rats differ in their responses to moderate, acute and reversible intraocular pressure elevation

TitlePigmented and albino rats differ in their responses to moderate, acute and reversible intraocular pressure elevation
Publication TypeJournal Article
Year of Publication2017
AuthorsGurdita, A., B. Tan, K. Joos, K. Bizheva, and V. Choh
JournalDocumenta Ophthalmologica
KeywordsA wave, acute disease, albinism, albino rat, amplitude modulation, analysis of variance, animal, animal experiment, animal tissue, Animals, Article, B wave, Brown Norway, brown Norway rat, controlled study, Cornea, dark adaptation, electroretinogram, electroretinography, Image analysis, immunohistochemistry, Inbred BN, indentation tonometer, intraocular hypertension, intraocular pressure, Long Evans rat, Long-Evans, male, nonhuman, Ocular Hypertension, optic nerve, Optical Coherence, Optical coherence tomography, oscillatory potential, pathophysiology, physiology, pigmented rat, priority journal, Rat, Rats, retina, retina and media testing equipment, retina ganglion cell, Retinal Ganglion Cells, Sprague Dawley rat, Sprague-Dawley, strain difference, Tomography, Ultrahigh-resolution optical coherence tomography, visual threshold

Purpose: To compare the electrophysiological and morphological responses to acute, moderately elevated intraocular pressure (IOP) in Sprague-Dawley (SD), Long-Evans (LE) and Brown Norway (BN) rat eyes. Methods: Eleven-week-old SD (n = 5), LE (n = 5) and BN (n = 5) rats were used. Scotopic threshold responses (STRs), Maxwellian flash electroretinograms (ERGs) or ultrahigh-resolution optical coherence tomography (UHR-OCT) images of the rat retinas were collected from both eyes before, during and after IOP elevation of one eye. IOP was raised to 35 mmHg for 1 h using a vascular loop, while the other eye served as a control. STRs, ERGs and UHR-OCT images were acquired on 3 days separated by 1 day of no experimental manipulation. Results: There were no significant differences between species in baseline electroretinography. However, during IOP elevation, peak positive STR amplitudes in LE (mean ± standard deviation 259 ± 124 µV) and BN (228 ± 96 µV) rats were about fourfold higher than those in SD rats (56 ± 46 µV) rats (p = 0.0002 for both). Similarly, during elevated IOP, ERG b-wave amplitudes were twofold higher in LE and BN rats compared to those of SD rats (947 ± 129 µV and 892 ± 184 µV, vs 427 ± 138 µV; p = 0.0002 for both). UHR-OCT images showed backward bowing in all groups during IOP elevation, with a return to typical form about 30 min after IOP elevation. Conclusion: Differences in the loop-induced responses between the strains are likely due to different inherent retinal morphology and physiology. © 2017, Springer-Verlag Berlin Heidelberg.