Metabolic Profiling of Mouse Brain Regions

The 6- and 12-month-old mice (n = 5–7) underwent MRI/MRS scanning to evaluate genotype- and treatment-induced differences in brain metabolites of FC and HIPP. MRI/MRS analyses were conducted at 4.7 T on a Varian/Agilent Inova horizontal bore system (Agilent, Palo Alto, USA) using a combination of volume and surface coil (RAPID Biomedical, Rimpar, Germany) according to a protocol described in Scuderi et al. (2018 (link)). Briefly, mice were anesthetized with isoflurane (IsoFlo, Abbott SpA, Berkshire, UK) 1.5–2.5% in O₂ 1 L/min. Anatomical T2-weighted sagittal MRIs were acquired for the positioning of the voxels for MRS. Localized 1H-MRS (PRESS TR/TE = 4,000/23 ms) were collected from HIPP and FC (volume 9.5 and 9.1 μl, respectively) as shown in Figure 4A, according to a quantitative protocol (Canese et al., 2012 (link)).
The following six metabolites were considered: N-acetyl-aspartate (NAA), myo-inositol (mINS), the sum of creatine and phosphocreatine (Cr + PCr), glutamate (Glu), glutamine (Gln), and total choline (tCho). Metabolite concentrations are expressed in mmol/L (mM). Moreover, we evaluated the NAA/Cr ratio and mINS/Cr.