title: Low-level laser irradiation induces in vitro proliferation of mesenchymal stem cells.
abstract: OBJECTIVE
  To evaluate the effect of low-level laser irradiation on the proliferation and possible nuclear morphological changes of mouse mesenchymal stem cells.
  
  
  METHODS
  Mesenchymal stem cells derived from bone marrow and adipose tissue were submitted to two applications (T0 and T48 hours) of low-level laser irradiation (660 nm; doses of 0.5 and 1.0 J/cm2). The trypan blue assay was used to evaluate cell viability, and growth curves were used to analyze proliferation at zero, 24, 48, and 72 hours. Nuclear alterations were evaluated by staining with DAPI (4'-6-diamidino-2-phenylindole) at 72 hours.
  
  
  RESULTS
  Bone marrow-derived mesenchymal stem cells responded to laser therapy in a dose-dependent manner. Higher cell growth was observed when the cells were irradiated with a dose of 1.0 J/cm2, especially after 24 hours (p<0.01). Adipose-derived mesenchymal stem cells responded better to a dose of 1.0 J/cm2, but higher cell proliferation was observed after 48 hours (p<0.05) and 72 hours (p<0.01). Neither nuclear alterations nor a significant change in cell viability was detected in the studied groups.
  
  
  CONCLUSIONS
  Low-level laser irradiation stimulated the proliferation of mouse mesenchymal stem cells without causing nuclear alterations. The biostimulation of mesenchymal stem cells using laser therapy might be an important tool for regenerative therapy and tissue engineering.
authors.affiliation: Universidade Federal do Rio Grande do Norte, Natal, RN, Brasil.
authors.forename: Carlos Augusto Galvão
authors.initials: CA
authors.lastname: Barboza
authors.affiliation: Universidade Federal do Rio Grande do Norte, Natal, RN, Brasil.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Ginani
authors.affiliation: Universidade Federal de Pernambuco, Recife, PE, Brasil.
authors.forename: Diego Moura
authors.initials: DM
authors.lastname: Soares
authors.affiliation: Universidade Federal do Rio Grande do Norte, Natal, RN, Brasil.
authors.forename: Aguida Cristina Gomes
authors.initials: AC
authors.lastname: Henriques
authors.affiliation: Universidade Federal do Rio Grande do Norte, Natal, RN, Brasil.
authors.forename: Roseana de Almeida
authors.initials: Rde A
authors.lastname: Freitas
mesh_terms: D000273:Adipose Tissue / Q000166:cytology; D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D054023:Lasers, Semiconductor / Q000627:therapeutic use; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000528:radiation effects*; D051379:Mice; D011829:Radiation Dosage; D015203:Reproducibility of Results; D013997:Time Factors
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