Quantitative Assessment of Metabolic Changes in the Developing Brain of C57BL/6 Mice by In Vivo Proton Magnetic Resonance Spectroscopy
- Corresponding Author:
- Andreas Schulze
The Hospital for Sick Children
The Research Institute, Genetics and Genome Biology
University of Toronto, 555 University Avenue
Toronto, ON, M5G 1X8, Canada
Tel: +1 (416) 813 7654
Fax: +1 (416) 813 5345
Received date: August 27, 2013; Accepted date: November 09, 2013; Published date: November 13, 2013
Citation: Schmitt B, vonBoth I, Amara CE, Schulze A (2013) Quantitative Assessment of Metabolic Changes in the Developing Brain of C57BL/6 Mice by In Vivo Proton Magnetic Resonance Spectroscopy. J Alzheimers Dis Parkinsonism 3:129. doi: 10.4172/2161-0460.1000129
Copyright: © 2013 Schmitt B, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Localized proton MRS was used to quantify cerebral metabolite concentrations in the thalamus of mice to assess the variation of major metabolites during brain development. Three sets of C57BL/6 mice were followed in a longitudinal study from a very early phase at post-natal day four (p4) until today 57 (p57). Experiments were conducted in accordance with Canadian animal care guidelines on a 7-Tesla small animal MR system. Specimens were examined under inhalation anesthesia using single-voxel MRS. A cubic volume with edge lengths of 1.9 mm was placed in the thalamus region of animals and point-resolved spectroscopy (PRESS) spectra were acquired with the following parameters (TR/TE/NEX=2500 ms/20 ms/600; Bandwidth=4000 Hz). Absolute metabolite quantification using LCModel was obtained by assigning water signal intensity measured by MRS to water concentrations determined by histobiochemical analysis and interpolation. Optimized anesthesia, immobilization, and careful monitoring led to a survival rate of 100% throughout the study. The brain water content was 84.8, 78.8, and 77.6% at p12, p31, and p66. Variation of metabolites revealed similar patterns for the total of creatine and phosphocreatine (tCr), glutamate and glutamine (Glx), and the total of N-acetyl aspartic compounds (tNAA), with steady increases from p4 to reaching a plateau after p21. The total of Cholinecontaining compounds (tCho) and myo-inositol (Ins) had high concentrations at early exam points, decreased to minima between p14 and p19, and increased to adult levels thereafter. Taurine (Tau) had highest levels at p4, decreased persistently but fast in the early development and slow in the later stages of brain development. Our results indicate that biological variance must be considered if results from studies on mouse models of pathologies are compared with results from healthy controls during development. This aspect seems to be especially important between p10 and p21. Due to the high temporal resolution used at early time points in our study and the inclusion of multiple groups of animals at time points, our data contribute important aspects to the existing literature about mouse brain development.