Retinal thickness changes over time in a AD mouse model (APPNL‐F/NL‐F) by SD‐OCT

Elena Salobrar‐Garcia,Lidia Sanchez‐Puebla,María Pilar Rojas Lozano,Inés López‐Cuenca,Jose Manuel Ramirez,Ana Isabel Ramirez,José A Fernández‐Albarral,Rosa De Hoz,Juan José Salazar Corral

doi:10.1111/aos.0092

Abstract

PurposeAlzheimer' disease (AD) is a neurodegenerative brain pathology, characterized by a loss of neuron and their synapses. Similar changes have been found in the retina even before appeared in the brain. The retina has been postulated as an accessible biomarker of AD. The aim of this study was to analyze changes in retinal thickness over time in a mouse model of AD (APPNL‐F/NL‐F).MethodsRetinas of male APPNL‐F/NL‐F (n = 55) and WT (n = 39) animals were evaluated in vivo by SD‐OCT at 6, 9, 12, 15, 17 and 20 months old. The mean total retinal thickness was analysed following the ETDRS sectors. To analyse the RNFL, axonal ring scan around the optic nerve head was carried out. RNFL was measured in six sectors provided by the manufacturer. Only the left eyes were used to study.ResultsIn the APPNL‐F/NL‐F group compared to WT animals, the total retinal thickness showed a slight thinning up to the 15 months old, this being significant only at 6 months in the outer temporal ring. At 17 months, there was thickening in the total retinal thickness being significant in the inferior and nasal sectors, both in inner and outer rings. At 20 months, there was a significant thinning in superior and temporal retina, both in inner and outer rings. RNFL thickness showed similar changes, that being only significates, the thinning in the global analysis and in nasal and inner‐temporal sectors at 6 months old.ConclusionsIn the mouse model of AD (APPNL‐F/NL‐F), there is a thinning of the retinal thickness up to 15 months, followed by a thickening at 17 months and a subsequent thinning at 20 months in some retinal areas. These changes over time are similar to those observed in the human retina, with areas of thinning, possibly caused by neurodegeneration, followed by thickening, possibly caused by deposits and neuroinflammation; this experimental AD model could help for an extensive understanding of the different retinal changes during the AD progression.

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