title: Low-level laser therapy improves skeletal muscle performance, decreases skeletal muscle damage and modulates mRNA expression of COX-1 and COX-2 in a dose-dependent manner.
abstract: We tested if modulation in mRNA expression of cyclooxygenase isoforms (COX-1 and COX-2) can be related to protective effects of phototherapy in skeletal muscle. Thirty male Wistar rats were divided into five groups receiving either one of four laser doses (0.1, 0.3, 1.0 and 3.0 J) or a no-treatment control group. Laser irradiation (904 nm, 15 mW average power) was performed immediately before the first contraction for treated groups. Electrical stimulation was used to induce six tetanic tibial anterior muscle contractions. Immediately after sixth contraction, blood samples were collected to evaluate creatine kinase activity and muscles were dissected and frozen in liquid nitrogen to evaluate mRNA expression of COX-1 and COX-2. The 1.0 and 3.0 J groups showed significant enhancement (P < 0.01) in total work performed in six tetanic contractions compared with control group. All laser groups, except the 3.0 J group, presented significantly lower post-exercise CK activity than control group. Additionally, 1.0 J group showed increased COX-1 and decreased COX-2 mRNA expression compared with control group and 0.1, 0.3 and 3.0 J laser groups (P < 0.01). We conclude that pre-exercise infrared laser irradiation with dose of 1.0 J enhances skeletal muscle performance and decreases post-exercise skeletal muscle damage and inflammation.
authors.affiliation: Post Graduate Program in Rehabilitation Sciences, Nove de Julho University (UNINOVE), São Paulo, SP, Brazil.
authors.forename: Patrícia
authors.initials: P
authors.lastname: de Almeida
authors.forename: Rodrigo Álvaro Brandão
authors.initials: RÁ
authors.lastname: Lopes-Martins
authors.forename: Shaiane Silva
authors.initials: SS
authors.lastname: Tomazoni
authors.forename: José Antônio
authors.initials: JA
authors.lastname: Silva
authors.forename: Paulo de Tarso Camillo
authors.initials: Pde T
authors.lastname: de Carvalho
authors.forename: Jan Magnus
authors.initials: JM
authors.lastname: Bjordal
authors.forename: Ernesto Cesar Pinto
authors.initials: EC
authors.lastname: Leal Junior
mesh_terms: D000818:Animals; D003402:Creatine Kinase / Q000097:blood; D051545:Cyclooxygenase 1 / Q000096:biosynthesis*; D051546:Cyclooxygenase 2 / Q000096:biosynthesis*; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation; D007537:Isometric Contraction / Q000528:radiation effects; D007834:Lasers; D008027:Light; D028022:Low-Level Light Therapy; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis*; D018763:Muscle Fatigue / Q000502:physiology / Q000528:radiation effects; D018482:Muscle, Skeletal / Q000502:physiology / Q000528:radiation effects*; D010807:Physical Endurance / Q000528:radiation effects*; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D008565:Membrane Proteins; D012333:RNA, Messenger; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496513:Ptgs1 protein, rat; C489691:Ptgs2 protein, rat; D003402:Creatine Kinase