title: Effects of low-level laser irradiation in ultrastructural morphology, and immunoexpression of VEGF and VEGFR-2 of rat masseter muscle.
abstract: The present study evaluates by ultrastructural and immunohistochemical methods, the possible changes on muscular tissue affected by LLLI during a treatment, for example, in cases of temporomandibular joint disorders. Sixty male Wistar rats divided into 6 groups (n=10) received ten laser irradiations, with different energy densities (groups I-0; II-0.5; III-1.0; IV-2.5; V-5.0; and VI-20 J/cm(2)). Muscles were removed and processed for transmission electron microscopic and immunohistochemical (VEGF and VEGFR-2) analyses. Captured photomicrographs of immunohistochemistry and transmission electron microscopy were evaluated. It was observed in the irradiated muscles, mitochondria of different shapes and sizes, with increased plasticity evidenced by organelles in fusion, division and the presence of elongated structures with characteristics of mitochondria, proximity with the dilated sarcoplasmatic reticulum, suggesting organelles with large amounts of energy, and the presence of cytoplasmic protrusions in the capillaries with high dosages. All studied groups showed immunostainings for both markers (VEGF and VEGFR-2), but in general those who received higher doses also showed the markings more pronounced, suggesting dose-dependent biomodulation. It was concluded that the LLLI was able to modify the ultrastructural characteristics and immunohistochemical pattern of VEGF and VEGFR-2 in the masseter muscle of rats.
authors.affiliation: Department of Morphology, Stomatology and Physiology, Faculty of Dentistry of Ribeirão Preto, University of São Paulo, Avenida do Café, s/n, Monte Alegre, 14040-904 Ribeirão Preto, SP, Brazil.
authors.forename: Fernando José
authors.initials: FJ
authors.lastname: Dias
authors.forename: João Paulo Mardegan
authors.initials: JP
authors.lastname: Issa
authors.forename: Ana Paula Amorim
authors.initials: AP
authors.lastname: Barbosa
authors.forename: Paulo Batista
authors.initials: PB
authors.lastname: de Vasconcelos
authors.forename: Ii-sei
authors.initials: IS
authors.lastname: Watanabe
authors.forename: Mamie
authors.initials: M
authors.lastname: Mizusakiiyomasa
mesh_terms: D000818:Animals; D007150:Immunohistochemistry; D007834:Lasers; D008297:Male; D008406:Masseter Muscle / Q000378:metabolism / Q000528:radiation effects* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D032342:Muscle Cells / Q000648:ultrastructure; D015388:Organelles / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000096:biosynthesis*
chemical_list: D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat; D040301:Vascular Endothelial Growth Factor Receptor-2