title: Laser phototherapy accelerates oral keratinocyte migration through the modulation of the mammalian target of rapamycin signaling pathway.
abstract: Keratinocytes play a central role in wound healing by responding to tissue injury through the activation of cellular proliferation and migration. Current clinical evidence suggests that the laser phototherapy (LPT) accelerates wound healing in a variety of oral diseases; however, the molecular mechanisms involved in response to LPT are not fully understood. Oral keratinocytes (NOK-SI) maintained under nutritional-deficit culture medium (2% fetal bovine serum) were irradiated with InGaAlP laser (660 nm; 40 mW; 0.04  cm2 spot size) in punctual and contact modes. The energy densities used were 4 and 20  J/cm2 corresponding to 4 and 20 s of exposure times and 0.16 and 0.8 J of energy per point, respectively. Three sessions of irradiations were applied with 6-h intervals. Further, the impact of LPT over cellular migration, proliferation, and activation of the mammalian target of rapamycin (mTOR) pathway, known to play a major role in epithelial migration and wound healing, was analyzed. Compared with control cells, the LPT-treated cells showed accelerated cellular migration without any changes in proliferation. Furthermore, LPT resulted in an increase in the phospho-S6 ribosomal protein, indicating activation of the mTOR signaling pathway. Collectively, these findings suggest that the LPT activates mTOR signaling pathway, promotes epithelial cell migration, and accelerates healing of oral mucosa.
authors: Universidade Federal do Rio Grande do Sul, School of Dentistry, Department of Oral Pathology, Porto Alegre, Rio Grande do Sul 90035-003, Brazil.
authors: Ana Carolina Amorim
authors: AC
authors: Pellicioli
authors: Universidade Federal do Rio Grande do Sul, School of Dentistry, Department of Oral Pathology, Porto Alegre, Rio Grande do Sul 90035-003, Brazil.
authors: Manoela Domingues
authors: MD
authors: Martins
authors: Universidade Federal do Rio Grande do Sul, School of Dentistry, Department of Oral Pathology, Porto Alegre, Rio Grande do Sul 90035-003, Brazil.
authors: Caroline Siviero
authors: CS
authors: Dillenburg
authors: University of São Paulo, School of Dentistry, Department of Dentistry, São Paulo, São Paulo 05508-000, Brazil.
authors: Márcia Martins
authors: MM
authors: Marques
authors: University of Michigan, School of Dentistry, Laboratory of Epithelial Biology, Department of Periodontics and Oral Medicine, Ann Arbor, Michigan 48109-1078.
authors: Cristiane H
authors: CH
authors: Squarize
authors: University of Michigan, School of Dentistry, Laboratory of Epithelial Biology, Department of Periodontics and Oral Medicine, Ann Arbor, Michigan 48109-1078.
authors: Rogerio M
authors: RM
authors: Castilho
mesh_terms: D000199:Actins / Q000378:metabolism; D000704:Analysis of Variance; D002465:Cell Movement / Q000528:radiation effects*; D049109:Cell Proliferation / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000528:radiation effects*; D028022:Low-Level Light Therapy / Q000379:methods*; D009061:Mouth Mucosa / Q000166:cytology; D058105:Polymerization; D015398:Signal Transduction / Q000528:radiation effects*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*
chemical_list: D000199:Actins; C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases