Effect of Compression Stress on the Expression of Integrin alpha5beta1 in Goat Temporomandibular Joint Disc Fibrochondrocytes from Self-Assembled Engineered Constructs

OBJECTIVE: The purpose of this study was to investigate the expression of integrin alpha5betal in native goat TMJ disc and its cultured cells in vitro and the effects of compression stress on the expression of integrin alpha5betal in TMJ disc self-assembled engineered constructs. Expression of integrin alpha5betal in native one-month-aged goat TMJ disc cells was examined by immunohistochemistry. TMJ disc cells were isolated from one-month-aged goat TMJ discs with 0.1% type I collagenase and passaged to P3 for the immunohistochemical staining of integrin alpha5betal. 2×10(6) cells was seeded into 5 mm diameter wells filled with 2% agarose gels to form self-assembled constructs. These constructs after 2 weeks were randomly divided into three groups: dynamic compression group at 0-0.2MPa, 1 Hz, 2hrs/d and static compression group at 0.2MPa, 2hrs/d and non-loaded control. At third week, general morphological and histological data of constructs were taken and IHC staining for constructs were analyzed quantitatively using Image-Pro Plus 6.0 analyzing system. Both fibroblast-like and chondrocyte-like cells in native goat TMJ disc were stained positive for integrin alpha5betal and mainly located in the cell membrane and cytoplasm. The self assembled constructs of the three treatment groups at 3 weeks were not shown morphologically different, although picrosirius red for collagen type I staining of dynamic compression group was more apparent than that of static compression and control groups. The IHC staining for integrin alpha5betal was globally uniformly distributed and dynamic compression group was more intensely and uniformly stained with a significantly higher mean optical density(OD) other groups (P<;0.05). Static compression group has an insignificantly lower mean OD value than control group (P>;0.05). Dynamic compression stress regulate integrin alpha5betal expression in goat TMJ disc and self-assembled construct and integrin alpha5betal may be involved in the mechanotransduction of goat TMJ disc self-assembled constructs under compression environment.