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Fatima Abbas, Anne M Hanneken, Frans Vinberg; Effect of Postmortem Time on Ex Vivo Human and Mouse Electroretinogram. Invest. Ophthalmol. Vis. Sci. 2019;60(9):4244.
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© ARVO (1962-2015); The Authors (2016-present)
Ex vivo Electroretinogram (ERG) on human research donor tissue is a valuable model to understand macular and peripheral retinal function in normal and diseased states. Since these results are dependent on death to enucleation times, harvesting conditions and cause of death, it is necessary to define the harvesting criteria of human autopsy eyes well in advance to ensure the viability of the postmortem retina. As a first step, we evaluated the effect of increasing postmortem death-to-enucleation times on inner and outer retinal function in the mouse eye to understand how delays in tissue procurement will alter the physiology of the retina.
We carried out ex vivo ERG recordings on isolated mouse retinas enucleated at several time-points post-euthanasia (0.25-4 hours). Mice used were of both sexes, and ranged in age from 2-4 months. We compared these results to ex vivo ERGs from human research donor eyes (Lion’s Eye Bank, Utah) obtained within 3-5 hours post-mortem. We measured light-evoked activity of the photoreceptors and inner retina by recording ex vivo ERG from patches of retina punched either from the macula or periphery.
We found that with increasing death-to-enucleation times ex vivo mouse ERGs show an initial rapid reduction (and eventual loss at 45 minutes post-mortem) of B-waves (n= 3 retinas/time point) followed by a more delayed decrease of A-waves which could be recorded up to 4 hours postmortem. Ex vivo ERGs from human research donor eyes enucleated 3-5 hours postmortem (n = 5 donors) also show no inner retinal signals, whilst photoreceptor signal was more reliably obtained, supporting the results with postmortem mouse retinas.
Through studying the effects of death-to-enucleation time on mouse retinal responses, we have determined that time to enucleation significantly affects both A- and B-waves, with B-waves more sensitive to the enucleation time and A-waves more resistant. This data potentially explains early results from our human donor retina ex vivo ERG experiments and will help to define the parameters and exclusion criteria for human autopsy eye tissue to ensure retinal viability.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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