Intermittent compressive force regulates matrix metalloproteinases and tissue inhibitors of metalloproteinases expression in human periodontal ligament cells

This study aims to evaluate the effects of intermittent compressive force (ICF) on the expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) by human periodontal ligament cells (hPDLCs). hPDLCs were subjected to ICF with a magnitude of 1.5 g/cm2 and loaded for 24 h. mRNA and protein expression of several MMPs and TIMPs were assessed using RT-PCR and ELISA analyses. An inhibitor of TGF-β (SB431542) was used to assess a possible role of TGF-β in the expression of MMPs and TIMPs under ICF. mRNA and protein analyses showed that ICF significantly induced expression of TIMP1 and TIMP3, but decreased expression of MMP1. Incubation with the TGF-β inhibitor and applied to ICF showed a downregulation of TIMP3, but expression of MMP1 was not affected. ICF is likely to affect ECM homeostasis by hPDLCs by regulating the expression of MMP1 and TIMPs. Moreover, TGF-β1 regulated expression of TIMP3. These findings suggest ICF may decrease the degradation of ECM and may thus be essential for maintaining PDL homeostasis.