title: Comparison of ionized calcium-binding adapter molecule 1 immunoreactivity of the hippocampal dentate gyrus and CA1 region in adult and aged dogs.
abstract: Similarities between age-related changes in the canine and human brain have resulted in the general acceptance of the canine brain as a model of human brain aging. The hippocampus is essentially required for intact cognitive ability and appears to be particularly vulnerable to the aging process. We observed changes in ionized calcium-binding adapter molecule 1 (Iba-1, a microglial marker) immunoreactivity and protein levels in the hippocampal dentate gyrus and CA1 region of adult (2-3 years) and aged (10-12 years) dogs. We also observed the interferon-gamma (IFN-gamma), a pro-inflammatory cytokine, protein levels in these groups. In the dentate gyrus and CA1 region of the adult dog, Iba-1 immunoreactive microglia were well distributed and their processes were highly ramified. However, in the aged dog, the processes of Iba-1 immunoreactive microglia were hypertrophied in the dentate gyrus. Moreover, Iba-1 protein level in the dentate gyrus in the aged dog was higher than in the adult dog. IFN-gamma expression was increased in the dentate gyrus homogenates of aged dogs than adult dogs. In addition, we found that some neurons were positive to Fluoro-Jade B (a marker for neuronal degeneration) in the dentate polymorphic layer, but not in the hippocampal CA1 region in the aged dog. These results suggest that Iba-1 immunoreactive microglia are hypertrophied in the dentate gyrus in the aged dog.
authors.affiliation: Department of Anatomy and Cell Biology, College of Veterinary Medicine and BK21 Program for Veterinary Science, Seoul National University, Seoul 151-742, South Korea.
authors.forename: In Koo
authors.initials: IK
authors.lastname: Hwang
authors.forename: Choong Hyun
authors.initials: CH
authors.lastname: Lee
authors.forename: Hua
authors.initials: H
authors.lastname: Li
authors.forename: Ki-Yeon
authors.initials: KY
authors.lastname: Yoo
authors.forename: Jung Hoon
authors.initials: JH
authors.lastname: Choi
authors.forename: Dae Won
authors.initials: DW
authors.lastname: Kim
authors.forename: Dong-Woo
authors.initials: DW
authors.lastname: Kim
authors.forename: Hong-Won
authors.initials: HW
authors.lastname: Suh
authors.forename: Moo-Ho
authors.initials: MH
authors.lastname: Won
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D003627:Data Interpretation, Statistical; D018891:Dentate Gyrus / Q000378:metabolism*; D004285:Dogs; D005452:Fluoresceins; D005456:Fluorescent Dyes; D007150:Immunohistochemistry; D007249:Inflammation / Q000473:pathology; D007371:Interferon-gamma / Q000378:metabolism; D008297:Male; D009930:Organic Chemicals
chemical_list: D002135:Calcium-Binding Proteins; D005452:Fluoresceins; D005456:Fluorescent Dyes; D009930:Organic Chemicals; C435731:fluoro jade; D007371:Interferon-gamma