title: The effect of low-intensity pulsed ultrasound on wound healing using scratch assay in epithelial cells.
abstract: OBJECTIVE
  Low-intensity pulsed ultrasound (LIPUS) is widely used in medical fields because it shortens the time required for biologic wound healing in fracture treatment. Also, in dental fields, LIPUS should be effectively employed for implant treatment. However, most of the relevant reports have been published on its effects on bone formation around implants, and the effects of LIPUS on soft tissue healing remain unclear. In the present study, we examined the effects of LIPUS on soft tissue healing using gingival epithelial cells.
  
  
  METHODS
  Gingival epithelial cells were cultured on a dish, followed by LIPUS exposure at a frequency of 3MHz for 15min. The cells were counted with a hemocytometer, and a scratch assay was conducted by measuring the closing area of the scratch wound using a microscope. Following LIPUS exposure, total RNA was collected for microarray analysis. In addition, real-time PCR was performed to examine the mRNA expression level of integrin α6β4. Furthermore, total protein was collected to examine the protein expression level of integrin α6β4 by western blotting.
  
  
  RESULTS
  The cell count and scratch assay demonstrated that LIPUS exposure promoted cell proliferation and scratch-wound closure. Microarray analysis demonstrated the increased expression levels of adhesion-related genes, including integrin. Real-time PCR analysis demonstrated that LIPUS exposure significantly up-regulated the mRNA expression level of integrin α6β4. Western blotting showed intense staining of integrin α6β4.
  
  
  CONCLUSIONS
  LIPUS exposure promotes wound closure in the scratch assay and up-regulates the expression level of integrin α6β4 as compared with the control.
authors.affiliation: Department of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Japan.
authors.forename: Yujiro
authors.initials: Y
authors.lastname: Iwanabe
authors.affiliation: Department of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Japan. Electronic address: masaki@kyu-dent.ac.jp.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Masaki
authors.affiliation: Department of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Tamura
authors.affiliation: Department of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Japan.
authors.forename: Shintaro
authors.initials: S
authors.lastname: Tsuka
authors.affiliation: Department of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Mukaibo
authors.affiliation: Department of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kondo
authors.affiliation: Department of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Japan.
authors.forename: Ryuji
authors.initials: R
authors.lastname: Hosokawa
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000235:genetics; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000502:physiology*; D005881:Gingiva / Q000166:cytology; D039161:Integrin alpha6beta4 / Q000235:genetics / Q000378:metabolism; D008810:Mice, Inbred C57BL; D012333:RNA, Messenger; D060888:Real-Time Polymerase Chain Reaction; D014464:Ultrasonic Therapy; D000069453:Ultrasonic Waves; D015854:Up-Regulation; D014945:Wound Healing / Q000235:genetics
chemical_list: D039161:Integrin alpha6beta4; D012333:RNA, Messenger
keywords: Integrin α6β4; LIPUS; Wound healing