title: Novel device for application of continuous mechanical tensile strain to mammalian cells.
abstract: During orthodontic tooth movement, the periodontal ligament (PDL) is exposed to continuous mechanical strain. However, many researchers have applied cyclic tensile strain, not continuous tensile strain, to PDL cellsin vitrobecause there has been no adequate device to apply continuous tensile strain to cultured cells. In this study, we contrived a novel device designed to apply continuous tensile strain to cells in culture. The continuous tensile strain was applied to human immortalized periodontal ligament cell line (HPL cells) and the cytoskeletal structures of HPL cells were examined by immunohistochemistry. The expression of both inflammatory and osteogenic markers was also examined by real-time reverse transcription polymerase chain reaction. The osteogenic protein, Osteopontin (OPN), was also detected by western blot analysis. The actin filaments of HPL cells showed uniform arrangement under continuous tensile strain. The continuous tensile strain increased the expression of inflammatory genes such asIL-1β,IL-6,COX-2andTNF-α, and osteogenic genes such asRUNX2andOPNin HPL cells. It also elevated the expression of OPN protein in HPL cells. These results suggest that our new simple device is useful for exploring the responses to continuous tensile strain applied to the cells.
authors.affiliation: Department of Orthodontics, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, Kanagawa 230-8501, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Wada
authors.affiliation: Department of Orthodontics, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, Kanagawa 230-8501, Japan kanzaki-h@tsurumi-u.ac.jp.
authors.forename: Hiroyuki
authors.identifier: http://orcid.org/0000-0003-3473-1218
authors.initials: H
authors.lastname: Kanzaki
authors.affiliation: Department of Orthodontics, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, Kanagawa 230-8501, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Narimiya
authors.affiliation: Department of Orthodontics, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, Kanagawa 230-8501, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Nakamura
keywords: Continuous tensile strain; Mechanical stress; Osteoblastic differentiation; Periodontal ligament cell; Simple stretch device