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In vivo imaging with a water immersion objective affects brain temperature, blood flow and oxygenation

  1. Morgane Roche
  2. Emmanuelle Chaigneau
  3. Ravi L Rungta
  4. Davide Boido
  5. Bruno Weber
  6. Serge Charpak  Is a corresponding author
  1. Université Paris Descartes, France
  2. University of Zurich, Switzerland
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Cite this article as: eLife 2019;8:e47324 doi: 10.7554/eLife.47324

Abstract

Previously, we reported the first oxygen partial pressure (Po2) measurements in the brain of awake mice, by performing two-photon phosphorescence lifetime microscopy at micrometer resolution (Lyons et al., 2016). However, this study disregarded that imaging through a cranial window lowers brain temperature, an effect capable of affecting cerebral blood flow, the properties of the oxygen sensors and thus Po2 measurements. Here, we show that in awake mice chronically implanted with a glass window over a craniotomy or a thinned-skull surface, the postsurgical decrease of brain temperature recovers within a few days. However, upon imaging with a water immersion objective at room temperature, brain temperature decreases by ~ 2-3{degree sign}C, causing drops in resting capillary blood flow, capillary Po2, hemoglobin saturation, and tissue Po2. These adverse effects are corrected by heating the immersion objective or avoided by imaging through a dry air objective, thereby revealing the physiological values of brain oxygenation.

Article and author information

Author details

  1. Morgane Roche

    INSERM U1128, Université Paris Descartes, Paris, France
    Competing interests
    The authors declare that no competing interests exist.
  2. Emmanuelle Chaigneau

    INSERM U1128, Université Paris Descartes, Paris, France
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-4282-1774
  3. Ravi L Rungta

    INSERM U1128, Université Paris Descartes, Paris, France
    Competing interests
    The authors declare that no competing interests exist.
  4. Davide Boido

    INSERM U1128, Université Paris Descartes, Paris, France
    Competing interests
    The authors declare that no competing interests exist.
  5. Bruno Weber

    Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
    Competing interests
    The authors declare that no competing interests exist.
  6. Serge Charpak

    INSERM U1128, Université Paris Descartes, Paris, France
    For correspondence
    serge.charpak@parisdescartes.fr
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5516-1245

Funding

Leducq Foundation (Understanding the role of the perivascular space in cerebral small vessel disease)

  • Morgane Roche

ERC (Imaging-in-the-Magnet)

  • Bruno Weber

The funders had no role in the decision to submit the work for publication.

Ethics

Animal experimentation: This study was performed in strict accordance with the recommendations by Inserm.All animal care and experimentation were performed in accordance with the INSERM Animal Care and Use Committee guidelines (protocol numbers CEEA34.SC.122.12 and CEEA34.SC.123.12).

Reviewing Editor

  1. David Kleinfeld, University of California, San Diego, United States

Publication history

  1. Received: April 2, 2019
  2. Accepted: August 8, 2019
  3. Accepted Manuscript published: August 9, 2019 (version 1)

Copyright

© 2019, Roche et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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