
Age-Related Neuronal Deterioration Specifically Within the Dorsal CA1 Region of the Hippocampus in a Mouse Model of Late Onset Alzheimer’s Disease
Author(s) -
Rasha H. Mehder,
Brian M. Bennett,
R. David Andrew
Publication year - 2021
Publication title -
journal of alzheimer's disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.677
H-Index - 139
eISSN - 1875-8908
pISSN - 1387-2877
DOI - 10.3233/jad-201024
Subject(s) - dendritic spine , oxidative stress , immunostaining , lipid peroxidation , hippocampal formation , hippocampus , endocrinology , medicine , biology , knockout mouse , senescence , neuroscience , pathology , microbiology and biotechnology , biochemistry , immunohistochemistry , receptor
Background: Neuronal damage resulting from increased oxidative stress is important in the development of late onset/age-related Alzheimer’s disease (LOAD). We have developed an oxidative stress–related mouse model of LOAD based on gene deletion of aldehyde dehydrogenase 2 (ALDH2), an enzyme important for the detoxification of endogenous aldehydes arising from lipid peroxidation. Compared to wildtype (WT) mice, the knockout (KO) mice exhibit AD-like pathologies and a progressive decline in recognition and spatial memory. This progression presumably has a morphological basis induced by oxidative damage. Objective: We performed morphometric analyses in the dorsal hippocampal CA1 region (dCA1) to determine if altered neuronal structure can help account for the progressive cognitive impairment in 3- to 12-month-old KO mice. Methods: Dendritic morphology was quantitatively analyzed by branched structured analysis and Sholl analysis following Golgi-Cox staining in WT mice (148 neurons) versus KO mice (180 neurons). Results: The morphology and complexity of dCA1 pyramidal neurons were similar at age 3 months in WTs and KOs. However, by 6 months there were significant reductions in apical and basal dendritic length, dendrite complexity, and spine density in KO versus WT mice that were maintained through ages 9 and 12 months. Immunostaining for protein adducts of the lipid peroxidation product 4-hydroxynonenal revealed significant increases in staining in dCA1 (but not ventral CA1) by 3 months, increasing through 12 months. Conclusion: This specific and progressive increase in dCA1 oxidative damage preceded detectable synaptic trimming in KO mice, in keeping with studies showing that lesions to dorsal hippocampus primarily impair cognitive memory.