title: Effect of low-level laser therapy after rapid maxillary expansion on proliferation and differentiation of osteoblastic cells.
abstract: The aim of this study was to investigate the osteoblastic activity of cells derived from the midpalatal suture upon treatment with low-level laser therapy (LLLT) after rapid maxillary expansion (RME). A total of 30 rats were divided into two groups: experimental I (15 rats with RME without LLLT) and experimental II (15 rats with RME + LLLT). The rats were euthanized at 24 h, 48 h, and 7 days after RME, when the osteoblastic cells derived from the rats' midpalatal suture were explanted. These cells were cultured for periods up to 17 days, and then in vitro osteogenesis parameters and gene expression markers were evaluated. The cellular doubling time in the proliferative stage (3-7 days) was decreased in cultured cells harvested from the midpalatal suture at 24 and 48 h after RME + LLLT, as indicated by the increased growth of the cells in a culture. Alkaline phosphatase activity at days 7 and 14 of the culture was increased by LLLT in cells explanted from the midpalatal suture at 24 and 48 h and 7 days after RME. The mineralization at day 17 was increased by LLLT after RME in all periods. Results from the real-time PCR demonstrated that cells harvested from the LLLT after RME group showed higher levels of ALP, Runx2, osteocalcin, type I collagen, and bone sialoprotein mRNA than control cells. More pronounced effects on ALP activity, mineralization, and gene expression of bone markers were observed at 48 h after RME and LLLT. These results indicate that the LLLT applied after RME is able to increase the proliferation and the expression of an osteoblastic phenotype in cells derived from the midpalatal suture.
authors.affiliation: Department of Pediatric Dentistry and Othodontic, School of Dentistry of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP, Brazil.
authors.forename: Ana Paula R Bernardes
authors.initials: AP
authors.lastname: da Silva
authors.forename: Alice D
authors.initials: AD
authors.lastname: Petri
authors.forename: Grasiele E
authors.initials: GE
authors.lastname: Crippa
authors.forename: Adriana Sasso
authors.initials: AS
authors.lastname: Stuani
authors.forename: Andrea Sasso
authors.initials: AS
authors.lastname: Stuani
authors.forename: Adalberto Luiz
authors.initials: AL
authors.lastname: Rosa
authors.forename: Maria Bernadete Sasso
authors.initials: MB
authors.lastname: Stuani
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism*; D000818:Animals; D002113:Calcification, Physiologic; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000528:radiation effects*; D049109:Cell Proliferation / Q000528:radiation effects*; D015870:Gene Expression; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism / Q000528:radiation effects; D010012:Osteogenesis / Q000528:radiation effects; D010155:Palatal Expansion Technique; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D000469:Alkaline Phosphatase