The Effect of Blood Contained in the Samples on the Metabolomic Profile of Mouse Brain Tissue: A Study by NMR Spectroscopy

Abstract

(1) Recently, metabolic profiling of the tissue in the native state or extracts of its metabolites has become increasingly important in the field of metabolomics. An important factor, in this case, is the presence of blood in a tissue sample, which can potentially lead to a change in the concentration of tissue metabolites and, as a result, distortion of experimental data and their interpretation. (2) In this paper, the metabolomic profiling based on NMR spectroscopy was performed to determine the effect of blood contained in the studied samples of brain tissue on their metabolomic profile. We used 13 male laboratory CD-1® IGS mice for this study. The animals were divided into two groups. The first group of animals (n = 7) was subjected to the perfusion procedure, and the second group of animals (n = 6) was not perfused. The brain tissues of the animals were homogenized, and the metabolite fraction was extracted with a water/methanol/chloroform solution. Samples were studied by high-frequency 1H-NMR spectroscopy with subsequent statistical data analysis. The group comparison was performed with the use of the Student’s test. We identified 36 metabolites in the brain tissue with the use of NMR spectroscopy. (3) For the major set of studied metabolites, no significant differences were found in the brain tissue metabolite concentrations in the native state and after the blood removal procedure. (4) Thus, it was shown that the presence of blood does not have a significant effect on the metabolomic profile of the brain in animals without pathologies.

Colitis-associated intestinal microbiota regulates brain glycine and host behavior in mice

“…To obtain protein-free extract of metabolites from the mouse brain, we used the following sample preparation protocol earlier evaluated for quantitative NMR-based metabolomics 95 . Briefly, brains were collected in 1.5 ml Eppendorf tubes and frozen in liquid nitrogen.…”

“…Amino acids, peptides, organic acids, alcohols, nucleotides, osmolytes, energy metabolism products were identified. The detailed description of metabolite quantification and validation are presented in our previous work 95 . The data is available at amdb.online/amdb/experiments/152/ (blood serum profiles), and amdb.online/amdb/experiments/154/ (brain profiles).…”

Colitis-associated intestinal microbiota regulates brain glycine and host behavior in mice

“…Amino acids, peptides, organic acids, alcohols, nucleotides, osmolytes, energy metabolism products were identified. The detailed description of metabolite quantification and validation are presented in our previous work (Glinskikh et al, 2021). The data is currently in the process of deposition to the public database and is available for the reviewers at amdb.online/amdb/experiments/152/ (blood serum profiles), amdb.online/amdb/experiments/154/ (brain profiles).…”

“…Amino acids, peptides, organic acids, alcohols, nucleotides, osmolytes, energy metabolism products were identified. The detailed description of metabolite quantification and validation are presented in our previous work (Glinskikh et al, 2021)…”

“…To obtain protein-free extract of metabolites from the mouse brain, we used the following sample preparation protocol earlier evaluated for quantitative NMR-based metabolomics (Glinskikh et al, 2021). Briefly, frozen brain tissue was weighed and homogenized using a glass homogenizer in cold (-20 °C) water/methanol/chloroform mixture in a ratio 1:2:2 (v/v; 1600 µL of solvent mixture per 150 mg of wet tissue), vortexed for 30 seconds, kept on ice for 10 minutes, and incubated at -20 °C for 20 minutes.…”