title: Low-level laser therapy induces an upregulation of collagen gene expression during the initial process of bone healing: a microarray analysis.
abstract: This study investigates the histological modifications produced by low level laser therapy (LLLT) on the first day of bone repair, as well as evaluates the LLLT effects on collagen expression on the site of a fracture. Twenty Wistar rats were distributed into a control group (CG) and a laser group (LG). Laser irradiation of Ga-Al-As laser 830 nm, 30 mW, 94 s, 2.8 J was performed in five sessions. Animals were euthanized on day 5 postsurgery. Histopathological analysis showed that LLLT was able to increase deposition of granulation tissue and newly formed bone at the site of the injury. In addition, picrosirius analysis showed that collagen fiber organization in the LG was enhanced compared to CG. Microarray analysis demonstrated that LLLT produced an upregulation type I collagen (COL-I). Immunohistochemical analysis revealed that the subjects that were treated presented a higher immunoexpression of COL-I. Our findings indicated that LLLT improves bone healing by producing a significant increase in the expression of collagen genes.
authors.affiliation: Federal University of São Paulo, Department of Bioscience, Avenue Ana Costa 95, Santos 11050-240, Brazil.
authors.forename: Carla Roberta
authors.initials: CR
authors.lastname: Tim
authors.affiliation: Federal University of São Paulo, Department of Bioscience, Avenue Ana Costa 95, Santos 11050-240, Brazil.
authors.forename: Paulo Sérgio
authors.initials: PS
authors.lastname: Bossini
authors.affiliation: Federal University of São Paulo, Department of Bioscience, Avenue Ana Costa 95, Santos 11050-240, Brazil.
authors.forename: Hueliton Wilian
authors.initials: HW
authors.lastname: Kido
authors.affiliation: Federal University of São Carlos, Department of Genetics and Evolution, Rod Washington Luis Km 235, São Carlos 13565-905, Brazil.
authors.forename: Iran
authors.initials: I
authors.lastname: Malavazi
authors.affiliation: University of São Paulo, School of Pharmaceutical Sciences of Ribeirão Preto, Department of Clinical Analysis, Toxicological and Bromatological, Avenue do Café 95, Ribeirão Preto, Brazil 14049-900, Brazil.
authors.forename: Marcia Regina
authors.initials: MR
authors.lastname: von Zeska Kress
authors.affiliation: State University of Campinas, Department of Genetics and Evolution, Cidade Universitária Zeferino Vaz, Campinas 13083-970, BrazileBrazilian National Center for Research in Energy and Materials, Brazilian Biosciences National Laboratory, Giuseppe Máximo Scolfaro 10.000, Campinas 13083-970, Brazil.
authors.forename: Marcelo Falsarella
authors.initials: MF
authors.lastname: Carazzolle
authors.affiliation: Federal University of São Paulo, Department of Bioscience, Avenue Ana Costa 95, Santos 11050-240, Brazil.
authors.forename: Ana Cláudia
authors.initials: AC
authors.lastname: Rennó
authors.affiliation: Federal University of São Carlos, Department of Physiotherapy, Rod Washington Luis Km 235, São Carlos 13565-905, Brazil.
authors.forename: Nivaldo Antonio
authors.initials: NA
authors.lastname: Parizotto
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000293:injuries; D003094:Collagen / Q000235:genetics*; D028022:Low-Level Light Therapy; D046228:Microarray Analysis; D051381:Rats; D017208:Rats, Wistar; D015854:Up-Regulation / Q000528:radiation effects*; D014945:Wound Healing / Q000235:genetics* / Q000528:radiation effects*
chemical_list: D003094:Collagen