Metabolism of the Periodontium Derived Cells Regulated by Mechanical Stress

机械应力在咀嚼相关牙周组织改建中的作用早已被人们所认识，但由于缺乏方便的体外实验模型，其机制的研究一直受到阻碍，我们设计了一个利用细胞培养技术来检测细胞对各种机械应力的代谢反应的实验。本实验中施加的机械力类型为：（1）拉伸力，（2）PEMF，和（3）胶原凝胶收缩力。来自条件培养基（CM）的生物信号可充当自分泌和/或旁分泌因子。通过细胞贴壁和铺展、^3 H-TdR掺入、细胞内钙离子、ALP活性和凝胶收缩等方法检测这些信号的变化。牵张强度对HPLF和HABC的CASFs分泌有显著影响，PEMF作用后HPLF细胞内钙离子浓度升高，可能是细胞增殖的第二信使。胶原蛋白凝胶的收缩受HPLF的调控，与CASFs共同孵育的HPLF对胶原蛋白凝胶的收缩有促进作用，因此，作用于活体组织的机械力比单纯的强力推动要复杂得多，但我们主要关注由于细胞拉伸、压缩以及PEMF的影响而引起的代谢变化。机械应力可诱导牙周组织细胞自分泌和旁分泌因子，从而导致牙周组织的改建。

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.