Low-level laser therapy (LLLT) reduces oxidative stress in primary cortical neurons in vitro

Authors

  • Ying-Ying Huang,

    1. Wellman Center for Photomedicine, Massachusetts General Hospital, 40 Blossom Street, Boston MA 02114, USA
    2. Department of Dermatology, Harvard Medical School, Boston MA, USA
    3. Department of Pathology, Guangxi Medical University, Nanning, Guangxi, China
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  • Kazuya Nagata,

    1. Wellman Center for Photomedicine, Massachusetts General Hospital, 40 Blossom Street, Boston MA 02114, USA
    2. Graduate School of Medicine, University of Tokyo, Japan
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  • Clark E. Tedford,

    1. PhotoThera Inc., Carlsbad, CA, USA
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  • Thomas McCarthy,

    1. PhotoThera Inc., Carlsbad, CA, USA
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  • Michael R. Hamblin

    Corresponding author
    1. Wellman Center for Photomedicine, Massachusetts General Hospital, 40 Blossom Street, Boston MA 02114, USA
    2. Department of Dermatology, Harvard Medical School, Boston MA, USA
    3. Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, USA
    • Phone: 617-726-6182, Fax: 617-726-8566
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Abstract

Low-level laser (light) therapy (LLLT) involves absorption of photons being in the mitochondria of cells leading to improvement in electron transport, increased mitochondrial membrane potential (MMP), and greater ATP production. Low levels of reactive oxygen species (ROS) are produced by LLLT in normal cells that are beneficial. We exposed primary cultured murine cortical neurons to oxidative stressors: hydrogen peroxide, cobalt chloride and rotenone in the presence or absence of LLLT (3 J/cm2, CW, 810 nm wavelength laser, 20 mW/cm2). Cell viability was determined by PrestoblueTM assay. ROS in mitochondria was detected using Mito-sox, while ROS in cytoplasm was detected with CellRoxTM. MMP was measured with tetramethylrhodamine. In normal neurons LLLT elevated MMP and increased ROS. In oxidatively-stressed cells LLLT increased MMP but reduced high ROS levels and protected cultured cortical neurons from death. Although LLLT increases ROS in normal neurons, it reduces ROS in oxidatively-stressed neurons. In both cases MMP is increased. These data may explain how LLLT can reduce clinical oxidative stress in various lesions while increasing ROS in cells in vitro. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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