Progressive, Age-Related Behavioral Impairments in Transgenic Mice Carrying both Mutant Amyloid Precursor Protein (APP) and Presenilin 1 (PS1) Transgenes

This study provides a comprehensive behavioral characterization during aging of transgenic mice bearing both presenilin-1 (PS1) and amyloid precursor protein (APP670,671) mutations. Doubly transgenic mice and non-transgenic controls were evaluated at ages wherein β-amyloid (Aβ) neuropathology in APP+PS1 mice is low (5–7 months) or very extensive (15–17 months). Progressive cognitive impairment was observed in transgenic mice for both water maze acquisition and radial arm water maze working memory. However, transgenicity did not affect Y-maze alternations, circular platform performance, standard water maze retention, or visible platform recognition at either age, nor did transgenicity affect anxiety levels in elevated plus-maze testing. In sensorimotor tasks, transgenic mice showed a progressive increase in open field activity, a progressive impairment in string agility, and an early-onset impairment in balance beam. None of these sensorimotor changes appeared to be contributory to any cognitive impairments observed, however. Non-transgenic mice showed no progressive behavioral change in any measure evaluated. Given the age-related cognitive impairments presently observed in APP+PS1 transgenic mice and their progressive Aβ deposition/neuroinflammation, Aβ neuropathology could be involved in these progressive cognitive impairments. As such, the APP+PS1 transgenic mouse offers unique opportunities to develop therapeutics to treat or prevent Alzheimer’s Disease through modulation of Aβ deposition/neuroinflammation