title: Low-level laser therapy (LLLT) reduces oxidative stress in primary cortical neurons in vitro.
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 Prestoblue™ assay. ROS in mitochondria was detected using Mito-sox, while ROS in cytoplasm was detected with CellRox™. 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.
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: Thomas
authors.initials: T
authors.lastname: McCarthy
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hamblin
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000528:radiation effects; D002540:Cerebral Cortex / Q000166:cytology*; D003593:Cytoplasm / Q000378:metabolism / Q000528:radiation effects; D005260:Female; D028022:Low-Level Light Therapy; D053078:Membrane Potential, Mitochondrial / Q000528:radiation effects; D051379:Mice; D008928:Mitochondria / Q000378:metabolism / Q000528:radiation effects; D009474:Neurons / Q000166:cytology / Q000378:metabolism* / Q000528:radiation effects*; D018384:Oxidative Stress / Q000528:radiation effects*; D011247:Pregnancy; D013481:Superoxides / Q000378:metabolism
chemical_list: D013481:Superoxides
keywords: cobalt chloride; cultured cortical neurons; hydrogen peroxide; low-level laser therapy; oxidative stress; reactive oxygen species