title: Voluntary exercise decreases amyloid load in a transgenic model of Alzheimer's disease.
abstract: Alzheimer's disease (AD) is a progressive neurodegenerative disorder for which there are few therapeutics that affect the underlying disease mechanism. Recent epidemiological studies, however, suggest that lifestyle changes may slow the onset/progression of AD. Here we have used TgCRND8 mice to examine directly the interaction between exercise and the AD cascade. Five months of voluntary exercise resulted in a decrease in extracellular amyloid-beta (Abeta) plaques in the frontal cortex (38%; p = 0.018), the cortex at the level of the hippocampus (53%; p = 0.0003), and the hippocampus (40%; p = 0.06). This was associated with decreased cortical Abeta1-40 (35%; p = 0.005) and Abeta1-42 (22%; p = 0.04) (ELISA). The mechanism appears to be mediated by a change in the processing of the amyloid precursor protein (APP) after short-term exercise, because 1 month of activity decreased the proteolytic fragments of APP [for alpha-C-terminal fragment (alpha-CTF), 54% and p = 0.04; for beta-CTF, 35% and p = 0.03]. This effect was independent of mRNA/protein changes in neprilysin and insulin-degrading enzyme and, instead, may involve neuronal metabolism changes that are known to affect APP processing and to be regulated by exercise. Long-term exercise also enhanced the rate of learning of TgCRND8 animals in the Morris water maze, with significant (p < 0.02) reductions in escape latencies over the first 3 (of 6) trial days. In support of existing epidemiological studies, this investigation demonstrates that exercise is a simple behavioral intervention sufficient to inhibit the normal progression of AD-like neuropathology in the TgCRND8 mouse model.
authors.affiliation: Institute for Brain Aging and Dementia, University of California, Irvine, Irvine, California 92697-4540, USA.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Adlard
authors.forename: Victoria M
authors.initials: VM
authors.lastname: Perreau
authors.forename: Viorela
authors.initials: V
authors.lastname: Pop
authors.forename: Carl W
authors.initials: CW
authors.lastname: Cotman
mesh_terms: D000544:Alzheimer Disease / Q000378:metabolism* / Q000534:rehabilitation*; D000682:Amyloid / Q000378:metabolism*; D053829:Amyloid Precursor Protein Secretases; D016564:Amyloid beta-Protein Precursor / Q000235:genetics; D000704:Analysis of Variance; D000818:Animals; D016282:Aspartic Acid Endopeptidases; D015153:Blotting, Western / Q000379:methods; D001921:Brain / Q000378:metabolism; D004195:Disease Models, Animal; D010450:Endopeptidases / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D010805:Physical Conditioning, Animal / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013997:Time Factors
chemical_list: D000682:Amyloid; D016564:Amyloid beta-Protein Precursor; D012333:RNA, Messenger; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509282:Bace1 protein, mouse