Effect of reducing isoflurane level on glucosamine uptake in the mouse brain during magnetic resonance imaging studies.

Publisher: Academic Press Country of Publication: United States NLM ID: 9215515 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1095-9572 (Electronic) Linking ISSN: 10538119 NLM ISO Abbreviation: Neuroimage Subsets: MEDLINE

Original Publication: Orlando, FL : Academic Press, c1992-

Isoflurane*/pharmacology ; Magnetic Resonance Imaging*/methods ; Glucosamine*/metabolism ; Anesthetics, Inhalation* ; Brain*/metabolism ; Brain*/diagnostic imaging ; Brain*/drug effects; Animals ; Mice ; Male ; Mice, Inbred C57BL ; Midazolam/pharmacokinetics

Anesthesia is often required during magnetic resonance imaging (MRI) examinations in animal studies. Anesthetic drugs differ in their capacity to interfere with homeostatic mechanisms responsible for glucose metabolism in the brain, which may create a constraint in the study design. Recent studies suggest that the chemical exchange saturation transfer (CEST) MRI scanning technique can detect localized metabolic changes in rodent brains induced by the uptake of glucose or its analogs; however, most of these studies do not account for the impact of anesthesia type on the brain metabolism. Herein, we aimed to evaluate the effect of reduced isoflurane levels on the preclinical imaging of glucosamine (GlcN) uptake in healthy mouse brains to establish optimal conditions for future brain imaging studies using the CEST MRI technique. The commonly used anesthesia protocol for longitudinal MRI examinations using 1.5% isoflurane level was compared to that using a mixture of low isoflurane (0.8%) level combined with midazolam (2 mg/kg, SC). Magnetization transfer ratio asymmetry (MTRasym) and area under the curve (AUC) analyses were used to characterize GlcN signals in the brain. The results indicated that mice injected with GlcN and anesthetized with 1.5% isoflurane exhibited low and insignificant changes in the MTRasym and AUC signals in the frontal cortex, whereas mice administered with 0.8% isoflurane combined with midazolam demonstrated a significant increase in these signals in the frontal cortex. This study highlights the diverse GlcN metabolic changes observed in mouse brains under variable levels of isoflurane anesthesia using the CEST MRI method. The results suggest that it is feasible to maintain anesthesia with low-dose isoflurane by integrating midazolam, which may enable the investigation of GlcN uptake in the brain. Thus, reducing isoflurane levels may support studies into mouse brain metabolism using the CEST MRI method and should be considered in future studies.
Competing Interests: Declaration of competing interest None.
(Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Keywords: Anesthesia; Brain metabolism; Chemical exchange saturation transfer; Glucosamine; Isoflurane; Magnetic resonance imaging

CYS9AKD70P (Isoflurane)
N08U5BOQ1K (Glucosamine)
0 (Anesthetics, Inhalation)
R60L0SM5BC (Midazolam)

Date Created: 20240620 Date Completed: 20240812 Latest Revision: 20240812

20240813

10.1016/j.neuroimage.2024.120691

38901773