title: The effects of low-level laser irradiation on bone tissue in diabetic rats.
abstract: Diabetes mellitus (DM) leads to a decrease in bone mass and increase the risk of osteoporosis and in this context, many treatments have shown to accelerate bone metabolism. It seems that low-level laser therapy (LLLT) is able of stimulating osteoblast activity and produced increased biomechanical properties. However, its effects on bone in diabetic rats are not fully elucidated. The aim of this study was to evaluate the effects of LLLT on bone formation, immunoexpression of osteogenic factors, biomechanical properties and densitometric parameters in diabetic rats. Thirty male Wistar rats were randomly distributed into three experimental groups: control group, diabetic group, and laser-treated diabetic group. DM was induced by streptozotocin (STZ) and after 1 week laser treatment started. An 830-nm laser was used, performed for 18 sessions, during 6 weeks. At the end of the experiment, animals were euthanized and tibias and femurs were defleshed for analysis. Extensive resorptive areas as a result of osteoclasts activity were noticed in DG when compared to control. Laser-treated animals showed an increased cortical area. The immunohistochemical analysis revealed that LLLT produced an increased RUNX-2 expression compared to other groups. Similar RANK-L immunoexpression was observed for all experimental groups. In addition, laser irradiation produced a statistically increase in fracture force, bone mineral content (BMC) and bone mineral density compared to DG. The results of this study indicate that the STZ model was efficient in inducing DM 1 and producing a decrease in cortical diameter, biomechanical properties and in densitometric variables. In addition, it seems that LLLT stimulated bone metabolism, decreased resorptive areas, increased RUNX-2 expression, cortical area, fracture force, BMD, and BMC. Further studies should be developed to provide additional information concerning the mechanisms of action of laser therapy in diabetic bone in experimental and clinical trials.
authors.affiliation: Department of Biotechnology, Federal University of São Carlos, Rod Washington Luis, Km 235, Monjolinho, São Carlos, São Paulo, Brazil, 13565-902.
authors.forename: Tatiane Lopes
authors.initials: TL
authors.lastname: Patrocínio-Silva
authors.forename: André Moreira Fogaça
authors.initials: AM
authors.lastname: de Souza
authors.forename: Raul Loppi
authors.initials: RL
authors.lastname: Goulart
authors.forename: Carolina Fuirini
authors.initials: CF
authors.lastname: Pegorari
authors.forename: Jussan Rodrigues
authors.initials: JR
authors.lastname: Oliveira
authors.forename: Kelly
authors.initials: K
authors.lastname: Fernandes
authors.forename: Angela
authors.initials: A
authors.lastname: Magri
authors.forename: Rosa Maria Rodrigues
authors.initials: RM
authors.lastname: Pereira
authors.forename: Daniel Ribeiro
authors.initials: DR
authors.lastname: Araki
authors.forename: Márcia Regina
authors.initials: MR
authors.lastname: Nagaoka
authors.forename: Nivaldo Antônio
authors.initials: NA
authors.lastname: Parizotto
authors.forename: Ana Cláudia Muniz
authors.initials: AC
authors.lastname: Rennó
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight; D015519:Bone Density; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism; D003720:Densitometry; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000473:pathology* / Q000503:physiopathology; D005269:Femur / Q000528:radiation effects*; D007150:Immunohistochemistry; D028022:Low-Level Light Therapy; D008297:Male; D053245:RANK Ligand / Q000378:metabolism; D017208:Rats, Wistar; D013311:Streptozocin; D013977:Tibia / Q000528:radiation effects*
chemical_list: D001786:Blood Glucose; D050659:Core Binding Factor Alpha 1 Subunit; D053245:RANK Ligand; D013311:Streptozocin