title: Low-level laser therapy (810 nm) protects primary cortical neurons against excitotoxicity in vitro.
abstract: Excitotoxicity describes a pathogenic process whereby death of neurons releases large amounts of the excitatory neurotransmitter glutamate, which then proceeds to activate a set of glutamatergic receptors on neighboring neurons (glutamate, N-methyl-D-aspartate (NMDA), and kainate), opening ion channels leading to an influx of calcium ions producing mitochondrial dysfunction and cell death. Excitotoxicity contributes to brain damage after stroke, traumatic brain injury, and neurodegenerative diseases, and is also involved in spinal cord injury. We tested whether low level laser (light) therapy (LLLT) at 810 nm could protect primary murine cultured cortical neurons against excitotoxicity in vitro produced by addition of glutamate, NMDA or kainate. Although the prevention of cell death was modest but significant, LLLT (3 J/cm(2) delivered at 25 mW/cm(2) over 2 min) gave highly significant benefits in increasing ATP, raising mitochondrial membrane potential, reducing intracellular calcium concentrations, reducing oxidative stress and reducing nitric oxide. The action of LLLT in abrogating excitotoxicity may play a role in explaining its beneficial effects in diverse central nervous system pathologies.
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, 40 Blossom Street, Boston MA 02114, USA; Department of Dermatology, Harvard Medical School, Boston MA, USA; Department of Pathology, Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Huang
authors.forename: Kazuya
authors.initials: K
authors.lastname: Nagata
authors.forename: Clark E
authors.initials: CE
authors.lastname: Tedford
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hamblin
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002470:Cell Survival / Q000528:radiation effects; D002540:Cerebral Cortex / Q000166:cytology*; D003593:Cytoplasm / Q000378:metabolism / Q000528:radiation effects; D005260:Female; D042541:Intracellular Space / Q000378:metabolism / Q000528:radiation effects; D028022:Low-Level Light Therapy; D053078:Membrane Potential, Mitochondrial / Q000528:radiation effects; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*; D009498:Neurotoxins / Q000633:toxicity*; D009569:Nitric Oxide / Q000096:biosynthesis; D011247:Pregnancy; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D009498:Neurotoxins; D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D000255:Adenosine Triphosphate; D002118:Calcium
keywords: cultured cortical neurons; excitotoxicity; kainic acid; low-level laser therapy; mitochondrial membrane potential glutamate. NMDA; reactive oxygen species