Author(s): Ning A, Cui J, To E, Ashe KH, Matsubara J
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Abstract PURPOSE: To compare the temporal and spatial expression patterns of amyloid precursor protein (APP), amyloid-beta deposits, inflammatory chemokines, and apoptosis in the retina of a mouse model of Alzheimer disease (AD). METHODS: Retinas of transgenic mice harboring a mutant presenilin (PS1) and a mutant APP gene were processed for TUNEL and immunohistochemistry with antibodies against APP, amyloid-beta, monocyte chemotactic protein (MCP)-1, and F4/80. Comparisons were made between age groups and between transgenic and wild-type congeners. RESULTS: The neuroretina demonstrated age-dependent increases in APP in the ganglion cells (RGCs) and in neurons of the inner nuclear layer (INL). Amyloid-beta demonstrated significant age-dependent deposition in the nerve fiber layer (NFL). TUNEL-positive RGC increased in an age-dependent fashion and in transgenic compared with wild-type congeners. Concomitant overexpression of MCP-1 and intense immunoreactivity for F4/80 suggested that RGCs upregulate MCP-1 in response to amyloid-beta. Activated microglia proliferated in response to MCP-1. In the outer retina, retinal pigment epithelium (RPE) demonstrated moderate age-dependent APP immunoreactivity, but nearby drusenlike deposits were not present. Amyloid-beta was observed in the choriocapillaris of the older animals. CONCLUSIONS: Amyloid-beta deposits accumulate with age in the retina of a transgenic mouse model of AD. The amyloid-beta loads are accompanied by increased immunoreactivity for MCP-1, F4/80, and TUNEL-positive profiles in the RGC layer. The results suggest that amyloid-beta causes neurodegeneration in the retina of the doubly mutant transgenic mouse model of AD.
This article was published in Invest Ophthalmol Vis Sci
and referenced in Journal of Addiction Research & Therapy