title: Low-level laser therapy stimulates the oxidative burst in human neutrophils and increases their fungicidal capacity.
abstract: Low-level laser therapy (LLLT) is known to enhance mitochondrial electron transfer and ATP production; thus, this study asked whether LLLT could stimulate the oxidative burst in human neutrophils (PMN) and improve their ability to kill microorganisms. Blood from healthy human subjects was collected and PMN were isolated from the samples. PMN were treated in vitro with 660 nm or 780 nm CW laser light at 40 mW power and increasing energies up to 19.2 J and were subsequently incubated with Candida albicans cells. Generation of hydroxyl radicals, hypochlorite anions and superoxide anions by PMN were checked using fluorescent probes and chemiluminescence assays; a microbicidal activity assay against C. albicans was also performed. LLLT excited PMN to a higher functional profile, which was translated as superior production of reactive oxygen species (ROS) and increased fungicidal capacity. The most efficacious energy was 19.2 J and, interestingly, the 660 nm light was even more efficacious than 780 nm at increasing the respiratory burst of PMN and the fungicidal capacity. Human neutrophils (PMN) were stimulated in vitro with 660 nm or 780 nm CW laser light at 40 mW of power and a total energy of 19.2 J. Low-level laser therapy (LLLT) excited PMN to a higher functional profile, which was translated as a superior production of reactive oxygen species (ROS) such as hydroxyl radicals (HO•) and hypochlorite anions (ClO-) (Figure) and increased fungicidal capacity against Candida albicans cells.
authors.affiliation: Department of Biochemistry, Institute of Biomedical Sciences, Federal University of Alfenas (UNIFAL-MG), Alfenas, MG 37130-000, Brazil.
authors.forename: Cláudio Daniel
authors.initials: CD
authors.lastname: Cerdeira
authors.affiliation: Department of Biochemistry, Institute of Biomedical Sciences, Federal University of Alfenas (UNIFAL-MG), Alfenas, MG 37130-000, Brazil.
authors.forename: Maísa Ribeiro Pereira
authors.initials: MR
authors.lastname: Lima Brigagão
authors.affiliation: Department of Clinics and Surgery, School of Dentistry, Federal University of Alfenas (UNIFAL-MG), Alfenas, MG 37130-000, Brazil.
authors.forename: Marina Lara
authors.initials: ML
authors.lastname: Carli
authors.affiliation: Department of Biochemistry, Institute of Biomedical Sciences, Federal University of Alfenas (UNIFAL-MG), Alfenas, MG 37130-000, Brazil.
authors.forename: Cláudia
authors.initials: C
authors.lastname: de Souza Ferreira
authors.affiliation: Department of Biochemistry, Institute of Biomedical Sciences, Federal University of Alfenas (UNIFAL-MG), Alfenas, MG 37130-000, Brazil.
authors.forename: Gabriel
authors.initials: G
authors.lastname: de Oliveira Isac Moraes
authors.affiliation: Department of Clinics and Surgery, School of Dentistry, Federal University of Alfenas (UNIFAL-MG), Alfenas, MG 37130-000, Brazil.
authors.forename: Henrique
authors.initials: H
authors.lastname: Hadad
authors.affiliation: Department of Clinics and Surgery, School of Dentistry, Federal University of Alfenas (UNIFAL-MG), Alfenas, MG 37130-000, Brazil.
authors.forename: João Adolfo
authors.initials: JA
authors.lastname: Costa Hanemann
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA.|Department of Dermatology, Harvard Medical School, Boston, MA 02115, USA.|Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hamblin
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA.|Department of Dermatology, Harvard Medical School, Boston, MA 02115, USA.|Department of Pathology and Parasitology, Institute of Biomedical Sciences, Federal University of Alfenas (UNIFAL-MG), Alfenas, MG 37130-000, Brazil.
authors.forename: Felipe Fornias
authors.initials: FF
authors.lastname: Sperandio
mesh_terms: D002176:Candida albicans; D006801:Humans; D028022:Low-Level Light Therapy; D009504:Neutrophils / Q000276:immunology / Q000528:radiation effects*; D017382:Reactive Oxygen Species / Q000378:metabolism; D016897:Respiratory Burst / Q000528:radiation effects*
chemical_list: D017382:Reactive Oxygen Species
keywords: Candida albicans; low-level laser therapy; neutrophils; oxidative burst; photobiomodulation; reactive oxygen species