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Original article
peer-reviewed

Alteration of Interneuron Immunoreactivity and Autophagic Activity in Rat Hippocampus after Single High-Dose Whole-Brain Irradiation



Abstract

The effects of high dose gamma radiation on brain tissue are poorly understood, with both limited and major changes reported. The present study compared the effects of gamma irradiation on the expression of interneuron markers within the hippocampal cornu ammonis 1 (CA1) region with expression in control matched rats. This area was chosen for study because of its well-characterized circuitry. Male Sprague-Dawley rats were exposed to 60 Gy of whole brain gamma radiation and after 24 or 48 hours, the brains were removed, fixed and sectioned to quantitate expression of parvalbumin (PV), calbindin-D28K (CB), reelin, neuropeptide-Y (NPY), and somatostatin. All of these markers increased in expression over the first 48 hours, except NPY, which decreased. This provides novel information on changes in gene expression in the hippocampal interneurons following radiation. Staining for Beclin 1, a marker of autophagy, increased most strongly in the subgranular zone (SGZ) of the dentate gyrus (DG). Overall, the results are consistent with the hypothesis that increased intracellular calcium follows irradiation, leading to an increased expression of calcium binding proteins. Increased autophagy occurs in the neurogenic zone of the dentate hilus, consistent with reduced effective neurogenesis after irradiation.



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Original article
peer-reviewed

Alteration of Interneuron Immunoreactivity and Autophagic Activity in Rat Hippocampus after Single High-Dose Whole-Brain Irradiation


Author Information

Yi-Bing Ouyang

Anesthesia, Stanford University School of Medicine

Shoucheng Ning

Department of Radiation Oncology, Stanford University Medical Center

John R. Adler

Department of Neurosurgery, Stanford University School of Medicine

Department of Radiation Oncology, Stanford University Medical Center

Bruce Maciver

Anesthesia, Stanford University School of Medicine

Susan J. Knox

Department of Radiation Oncology, Stanford University Medical Center

Rona Giffard Corresponding Author

Anesthesia, Stanford University School of Medicine


Ethics Statement and Conflict of Interest Disclosures

Human subjects: This study did not involve human participants or tissue. Animal subjects: All experiments were performed according to a protocol approved by the Stanford University Administrative Panel for Laboratory Animal Care. Issued protocol number 9297. Conflicts of interest: The authors have declared that no conflicts of interest exist.


Original article
peer-reviewed

Alteration of Interneuron Immunoreactivity and Autophagic Activity in Rat Hippocampus after Single High-Dose Whole-Brain Irradiation


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Original article
peer-reviewed

Alteration of Interneuron Immunoreactivity and Autophagic Activity in Rat Hippocampus after Single High-Dose Whole-Brain Irradiation

  • Author Information
    Yi-Bing Ouyang

    Anesthesia, Stanford University School of Medicine

    Shoucheng Ning

    Department of Radiation Oncology, Stanford University Medical Center

    John R. Adler

    Department of Neurosurgery, Stanford University School of Medicine

    Department of Radiation Oncology, Stanford University Medical Center

    Bruce Maciver

    Anesthesia, Stanford University School of Medicine

    Susan J. Knox

    Department of Radiation Oncology, Stanford University Medical Center

    Rona Giffard Corresponding Author

    Anesthesia, Stanford University School of Medicine


    Ethics Statement and Conflict of Interest Disclosures

    Human subjects: This study did not involve human participants or tissue. Animal subjects: All experiments were performed according to a protocol approved by the Stanford University Administrative Panel for Laboratory Animal Care. Issued protocol number 9297. Conflicts of interest: The authors have declared that no conflicts of interest exist.

    Acknowledgements


    Article Information

    Published: June 30, 2017

    DOI

    10.7759/cureus.1414

    Cite this article as:

    Ouyang Y, Ning S, Adler J R., et al. (June 30, 2017) Alteration of Interneuron Immunoreactivity and Autophagic Activity in Rat Hippocampus after Single High-Dose Whole-Brain Irradiation. Cureus 9(6): e1414. doi:10.7759/cureus.1414

    Publication history

    Received by Cureus: April 19, 2017
    Peer review began: June 08, 2017
    Peer review concluded: June 23, 2017
    Published: June 30, 2017

    Copyright

    © Copyright 2017
    Ouyang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License CC-BY 3.0., which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

    License

    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.

Abstract

The effects of high dose gamma radiation on brain tissue are poorly understood, with both limited and major changes reported. The present study compared the effects of gamma irradiation on the expression of interneuron markers within the hippocampal cornu ammonis 1 (CA1) region with expression in control matched rats. This area was chosen for study because of its well-characterized circuitry. Male Sprague-Dawley rats were exposed to 60 Gy of whole brain gamma radiation and after 24 or 48 hours, the brains were removed, fixed and sectioned to quantitate expression of parvalbumin (PV), calbindin-D28K (CB), reelin, neuropeptide-Y (NPY), and somatostatin. All of these markers increased in expression over the first 48 hours, except NPY, which decreased. This provides novel information on changes in gene expression in the hippocampal interneurons following radiation. Staining for Beclin 1, a marker of autophagy, increased most strongly in the subgranular zone (SGZ) of the dentate gyrus (DG). Overall, the results are consistent with the hypothesis that increased intracellular calcium follows irradiation, leading to an increased expression of calcium binding proteins. Increased autophagy occurs in the neurogenic zone of the dentate hilus, consistent with reduced effective neurogenesis after irradiation.



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Create a free account to continue reading this article.

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Yi-Bing Ouyang

Anesthesia, Stanford University School of Medicine

Shoucheng Ning

Department of Radiation Oncology, Stanford University Medical Center

John R. Adler, M.D.

Department of Neurosurgery, Stanford University School of Medicine

Bruce Maciver, Ph.D., M.Sc., Professor

Anesthesia, Stanford University School of Medicine

Susan J. Knox

Department of Radiation Oncology, Stanford University Medical Center

Rona Giffard

Anesthesia, Stanford University School of Medicine

For correspondence:
rona.giffard@stanford.edu

Yi-Bing Ouyang

Anesthesia, Stanford University School of Medicine

Shoucheng Ning

Department of Radiation Oncology, Stanford University Medical Center

John R. Adler, M.D.

Department of Neurosurgery, Stanford University School of Medicine

Bruce Maciver, Ph.D., M.Sc., Professor

Anesthesia, Stanford University School of Medicine

Susan J. Knox

Department of Radiation Oncology, Stanford University Medical Center

Rona Giffard

Anesthesia, Stanford University School of Medicine

For correspondence:
rona.giffard@stanford.edu