RESUMEN
Objective To investigate the relationship between learning and memory deficit and demyelination of the corpus callosum in twelve-month old APP/PS1 transgenic mice. Methods Twelve twelve-month old APP/PS1 transgenic mice were as AD group, and age-matched wild type (WT) littermates were as WT group. Learning and memory ability was tested with Morris water maze, and the mor-phology of nerve fiber of corpus callosum was detected with Luxol Fast Blue staining. Immunohistochemistry was used to detect myelin ba-sic protein (MBP) in the corpus callosum. Thioflavine S staining was used to detect amyloid plaque in the corpus callosum. Results Com-pared with WT group, the latency increased (Z>2.873, P<0.01) and the times crossing the location of the platform decreased (t=-7.339, P<0.001) in AD group. The nerve fibers were sparse and disorganized, with a lot of vacuoles in the corpus callosum of AD group. The positive expression of MBP in the corpus callosum was significantly decreased (t=-4.481, P<0.001) in AD group compared with WT group. There were amyloid plaques in the corpus callosum of AD group. Conclusion Twelve-month old APP/PS1 transgenic mice exhibit learning and memory deficit, which may be attributed to the deposition of the amyloid plaque mediated demyelinated injury of the corpus callosum.