In vivo 9.4T 1H MRS for evaluation of brain metabolic changes in the Ts65Dn mouse model for Down syndrome

Purpose: Down Syndrom (DS) (human trisomy 21) is a chromosomal abnormality characterized by the presence of an additional copy of some genes on chrosome 21. This pathology is characterized by a set of behavioural, morphological and metabolic alterations. Ts65Dn model is the most widely studied mice model for DS. This mouse is trisomic for the chromosome 16 which is homologous to human chromosome 21. Some studies have been performed on Ts65Dn mice on the hippocampus and the cerebellum but never in vivo with MRS. The aim of this study was to quantify changes in brain metabolites for TS65Dn mice compared to disomic mice with 9.4T Magnetic Resonance Spectroscopy (MRS). Material and methods: 20 mice were used in this study. They were divided into two groups: Ts65Dn and disomic (2n) mice. MR experiments were performed on a 9.4 T horizontal magnet (94/20 USR Bruker Biospec, Wissembourg, France) with a 35mm diameter birdcage coil. A PRESS sequence (TR=4s, TE=15ms) with water supression (VAPOR) and Outer Volume Supression (OVS) was used to record 1H spectra in a 2*2*2mm voxel in the hippocampus and in the cerebellum. 256 scan were performed for a total acquisition duration of 17 min. Several metabolites (NAA, choline, myo-inositol, glutamate, glutamine) were then quantified on the spectra with JMRUI3.0 (2001, www.mrui.uab.es/mrui/). Results: Quantification of metabolites for both cerebellum and hippocampus are presented tables 1 and 2: HIPPOCAMPUS 2n (n=10) Ts65Dn (n=10) % change p value Cr+PCr=Cx 18865 (430) 20198 (510) 10% NS