Metabolism of the Periodontium Derived Cells Regulated by Mechanical Stress

机械应力在调节与咀嚼有关的牙周组织重塑中的作用早已被认识到，但由于缺乏方便的体外实验模型，对其机制的研究一直受到阻碍。我们设计了一个实验，利用细胞培养技术来测量细胞对各种机械力的代谢反应。本实验中施加的机械力类型为：(1)拉伸力，(2)PEMF,(3)凝胶收缩力。来自条件介质（CM）的生物信号可能起自分泌和/或旁分泌因子的作用。这些信号也通过细胞附着和扩散、^3H-TdR掺入、细胞内钙、ALPase和凝胶收缩来检测。Flexercell应变单元的机械拉伸刺激了HABC细胞的生长，提高了HPLF和HABC的ALPase活性。HPLF和HABC的casf分泌受拉伸强度所产生的机械应力的显著影响。与PEMF接触的HPLF细胞内钙水平升高，这可能是细胞增殖的第二信使。HPLF可调节胶原凝胶的收缩，与casf孵养的HPLF可刺激凝胶收缩。因此，施加在活组织上的机械力比单纯的强力推动更复杂，但我们关注的是由于细胞拉伸、压缩和PEMF的影响而引起的代谢改变。机械应力可诱导细胞自分泌和旁分泌因子，引起牙周组织的重塑。

The role of mechanical tress in regulating remodeling of periodontium concenrned with the mastication has long been recognized,but the investigation of mechanisms involved has been hampered by the absence of convinient experimental models in vitro.We designed an experiment using the cell culture technique to measure cell metabolic response to a variety of mechanical forces. The types of mechanical force applied in this experiment were :(1)stretching force,(2)PEMF,and (3)collegen gel contraction force. The biological signals from the conditioned medium(CM) which may play act as autocrine and/or paracrine factor. These signals were also examined by cell attachment and spreading,^3H-TdR incorporation,intracellular calcium,ALPase and gel contraction.The mechanical stretching used by Flexercell strain unit stimulated the cell growth of HABC and increased the ALPase activity of HPLF and HABC. The secreation of CASFs of HPLF and HABC was dramatically affected by the mechanical stress obtained with the magnitude of stretching.HPLF exposed with PEMF was increased the intracellular calcium level which could be a second messenger of cell proliferation. The contraction of collagen gel was modulated by HPLF,and the HPLF incubated with CASFs stimulated the gel contraction.Therefore,mechanical forces applied on the living tissue are more complex than merely forceful pushing,but we focused on the metabolic alteration due to cell stretching,compression and the effect of PEMF. There mechanical stresses may induce cell autocrine and paracrine factors which results in the remodeling of periodontium.