title: Immune marker CD68 correlates with cognitive impairment in normally aged rats.
abstract: The relationship between heightened neuroinflammation and cognitive decline in the normally aged brain is still debatable, as most data are derived from insult-related models. Accordingly, the aim of the current study was to determine whether a link could be established for 2 immune markers at the post-transcriptional level; CD68 and MHC-II, in a normally aged (24-month-old) rat population discriminated for their learning abilities. Using the Morris Water Maze (MWM) task, aged rats were divided into aged learning-impaired (AI) or -unimpaired (AU) groups. Western immunoblots of hippocampal tissue revealed a significant increase of CD68 in AI rats compared to the AU group. Moreover, up-regulated CD68 expression correlated with increased latency times in the MWM task. Immunofluorescence for CD68 revealed intense staining in the white matter regions and CA3 subregion of the hippocampus in the AI group. Despite expression of MHC-II in the AI group, no correlation was found. Overall, these data suggest that CD68 could play a role associated with cognitive decline in a subgroup of the normally aged population.
authors.affiliation: Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montréal, Québec, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Farso
authors.forename: Caroline
authors.initials: C
authors.lastname: Ménard
authors.forename: Jessica
authors.initials: J
authors.lastname: Colby-Milley
authors.forename: Rémi
authors.initials: R
authors.lastname: Quirion
mesh_terms: D000375:Aging / Q000276:immunology*; D000818:Animals; D015703:Antigens, CD / Q000276:immunology* / Q000378:metabolism*; D015214:Antigens, Differentiation, Myelomonocytic / Q000276:immunology* / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000276:immunology / Q000378:metabolism; D060825:Cognitive Dysfunction / Q000276:immunology* / Q000378:metabolism; D000949:Histocompatibility Antigens Class II / Q000276:immunology / Q000378:metabolism; D008297:Male; D051381:Rats; D020318:Rats, Long-Evans; D015854:Up-Regulation; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D015415:Biomarkers; D000949:Histocompatibility Antigens Class II; C539355:CD68 protein, rat; D000097382:CD68 Molecule