title: Influence of low-level laser therapy on wound healing in nicotine-treated animals.
abstract: Low-level laser therapy (LLLT) has been shown to have several biological effects that favor the healing process, and nicotine has been shown to delay the healing process. In this study we investigated the healing of open wounds created on the back of rats treated with nicotine with or without LLLT. Of 115 animals, 59 received subcutaneous injections of saline solution, and the others received subcutaneous injections of nicotine (3 mg/kg body weight), twice a day throughout the study period. After 30 days, skin wounds were created on the back of the animals. The animals receiving saline injections were divided into two groups: group 1 (G1, n = 29), in which the wounds were left untreated, and group 2 (G2, n = 30), in which the wounds were treated with LLLT (GaAlAs, 660 nm, 30 mW, 5.57 J/cm(2) per point, 0.39 J, 13 s per point, 0.42 W/cm(2)). The animals receiving nicotine injections were also divided into two groups: group 3 (G3, n = 29), in which the wounds were left untreated, and group 4 (G4, n = 27), in which the wounds were treated with LLLT. The animals were killed 3, 7 or 14 days after surgery. Wound healing was evaluated histologically both qualitatively and semiquantitatively. Wounds of G2 showed a delay in epithelial migration and connective tissue organization compared to those of G1. Wounds of G2 showed faster healing than those of G1; similarly, wounds of G4 showed more advanced healing than those of G3. LLLT acted as a biostimulatory coadjuvant agent balancing the undesirable effects of nicotine on wound tissue healing.
authors.affiliation: Department of Surgery and Integrated Clinic, Division of Periodontics, Univ Estadual Paulista, Araçatuba, São Paulo, Brazil. vgouveia@foa.unesp.br
authors.forename: Valdir Gouveia
authors.initials: VG
authors.lastname: Garcia
authors.forename: Valmir Campos
authors.initials: VC
authors.lastname: Macarini
authors.forename: Juliano Milanezi
authors.initials: JM
authors.lastname: de Almeida
authors.forename: Alvaro Francisco
authors.initials: AF
authors.lastname: Bosco
authors.forename: Maria José Hitomi
authors.initials: MJ
authors.lastname: Nagata
authors.forename: Tetuo
authors.initials: T
authors.lastname: Okamoto
authors.forename: Mariéllen
authors.initials: M
authors.lastname: Longo
authors.forename: Letícia Helena
authors.initials: LH
authors.lastname: Theodoro
mesh_terms: D000818:Animals; D054023:Lasers, Semiconductor / Q000627:therapeutic use; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D051381:Rats; D012867:Skin / Q000473:pathology / Q000503:physiopathology / Q000528:radiation effects*; D014945:Wound Healing / Q000187:drug effects / Q000528:radiation effects*
chemical_list: D009538:Nicotine