Magnetic resonance spectroscopy analysis of neurochemical changes in the atrophic hippocampus of APP/PS1 transgenic mice

Alzheimer's disease (AD) is characterized by neuropathological changes and progressive cognitive decline, which is associated with the volume loss and neurochemical alterations. However, the specific neurochemical alterations in cerebral regions that contribute to cognitive decline still remain unknown. In the present study, we measured cerebral morphological and neurochemical alterations using structural magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (1H-MRS) in an AD model of APP/PS1 transgenic mice. Voxel-based morphometry (VBM) analysis indicated atrophy of the hippocampus, motor cortex, striatum, amygdaloid body, septal area, bed nucleus of the stria terminalis and accumbens nucleus in APP/PS1 transgenic mice. Furthermore, the hippocampus was selected as a region of interest (ROI) to explore neurochemical metabolism. The results showed that the ratios of N-acetylaspartate/creatine (NAA/Cr) and glutamate/creatine (Glu/Cr) were reduced, while myo-inositol/creatine (mIn/Cr) was increased in APP/PS1 transgenic mice compared to the wild type mice and accompanied by a decline in learning and memory. Taken together, the present study suggests that hippocampal atrophy and neurochemical changes in NAA, Glu and mIn may play a causative role in the cognitive decline associated with AD.