Lasers in Medical Science

, Volume 28, Issue 3, pp 777–783

Zymographic and ultrastructural evaluations after low-level laser irradiation on masseter muscle of HRS/J strain mice

  • Mamie Mizusaki Iyomasa
  • Elen Camargo Rizzi
  • Juliane Caroline Leão
  • João Paulo Mardegan Issa
  • Fernando José Dias
  • Yamba Carla Lara Pereira
  • Maria José Vieira Fonseca
  • Fabiana Testa Moura de Carvalho Vicentini
  • Ii-sei Watanabe
Original Article

DOI: 10.1007/s10103-012-1156-6

Cite this article as:
Iyomasa, M.M., Rizzi, E.C., Leão, J.C. et al. Lasers Med Sci (2013) 28: 777. doi:10.1007/s10103-012-1156-6

Abstract

Low-level laser therapy (LLLT) has been widely used in the treatment of the stomatognathic system dysfunction; however, its biological effect remains poorly understood. This study evaluated the effect of LLLT (GaAlAs, 780 nm, 20 J/cm², 40 mW) on masseter muscle of HRS/J mice after different numbers of laser irradiations (three, six, and ten) for 20 s in alternate days. Three experimental groups were defined according to the number of laser irradiations and three control groups (n = 5) were used. On the third day after the last irradiation, all animals were killed and the masseter muscle was removed and processed for the following analysis: (a) transmission electron microscopy, (b) zymography, (c) immunohistochemistry for vascular endothelial growth factor (VEGF) and VEGFR-2. The results showed: (a) with six laser applications, a dilation of T tubules, and sarcoplasmic reticulum cistern, increased pinocytosed vesicles in the endothelium; with ten laser applications, few pinocytic vesicles in the endothelium and condensed mitochondria. (b) Under the conditions of this study, the synthesis of other matrix metalloproteinases was not observed, only the MMP-2 and -9. (c) After ten laser irradiations, immunostaining was observed only for VEGFR-2. We conclude that after six laser applications, ultrastructural changes may facilitate the Ca+2 transfer to cytosol and increase the fluid transport from one surface to another. The ultrastructural changes and no immunostaining for VEGF with ten applications may decrease the metabolic activity as well as damage the angiogenic process, suggesting that an effective number of laser applications may be less than ten, associating to this therapy a better cost–benefit.

Keywords

Low-level laser therapyMasseter muscleTransmission electron microscopyZymographyVEGFVEGFR-2

Copyright information

© Springer-Verlag London Ltd 2012

Authors and Affiliations

  • Mamie Mizusaki Iyomasa
    • 1
  • Elen Camargo Rizzi
    • 1
  • Juliane Caroline Leão
    • 1
  • João Paulo Mardegan Issa
    • 1
  • Fernando José Dias
    • 1
  • Yamba Carla Lara Pereira
    • 1
  • Maria José Vieira Fonseca
    • 2
  • Fabiana Testa Moura de Carvalho Vicentini
    • 2
  • Ii-sei Watanabe
    • 3
  1. 1.Department of Morphology, Stomatology and Physiology, Faculty of Dentistry of Ribeirão PretoUniversity of São PauloRibeirão PretoBrazil
  2. 2.Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences of Ribeirão PretoUniversity of São PauloRibeirão PretoBrazil
  3. 3.Department of Anatomy, Institute of Biomedical Sciences—ICBUniversity of São PauloRibeirão PretoBrazil