Cyclic tensile strain enhances the expression of Indian hedgehog and progression of ossification of the human cervical posterior longitudinal ligament

The initiation and/or progression of ossification of the posterior longitudinal ligament (OPLL) is associated with cyclic tensile strain, but the pathomechanism of OPLL remains unclear. Indian hedgehog (Ihh) and its related signaling are key factors in normal enchondral ossification. However, the relation of OPLL to Ihh is unclear. The purpose of this study is to investigate the contribution of mechanical strain to OPLL and the relation of Ihh to OPLL. Cultured posterior longitudinal ligament cells were subjected to 24 hours of cyclic tensile strain and then analyzed by microarray.