Examination on the role and the proliferation mechanism of the epithelial rests of Malassez.

用免疫组织化学方法观察了炎症细胞、上皮细胞(ERM)和神经纤维在大鼠根尖周炎模型中的分布。在根尖牙周组织中，炎性细胞浸润，神经纤维密度增加，呈时间依赖性。而在颈部和分叉牙周组织中，未观察到严重的炎症反应，神经纤维密度与对照组相比无明显变化。组织学上未发现ERM和神经纤维之间的交叉关系。在这种情况下，ERM的扩散没有得到承认。而牙髓底意外穿孔大鼠术后6周，牙周组织出现严重的炎症反应，并可见大量的ERM。提示炎症因子可能参与了ERM的增殖。在颈部和分叉牙周组织中，ERM和成骨细胞呈TrkA免疫反应阳性。术后随着时间的推移，ERM和成骨细胞的免疫反应性均下降。值得注意的是，成骨细胞分布在与ERM相对的部位，TrkA免疫反应弱或阴性，数量减少，TrkA免疫反应弱或阴性。据报道，磨牙分叉区是牙槽骨和牙周膜活跃改建的区域。提示成纤维细胞来源的NGF受成牙本质细胞受体介导的内化作用，可能对成牙本质细胞起调控作用。考虑到这些发现，TrkA阳性的ERM可能在调节颈部和分叉牙周组织的骨重建中发挥重要作用。

We examined immunohistochemically the distribution of inflammatory cells, epithelial rests of Malassez (ERM) and nerve fibers in induced rat periapical lesion. In the apical periodontium, inflammatory cells infiltrated and nerve fibers increased in density in a time dependent fashion. In the cervical and bifurcational periodontium, however, severe inflammatory reactions were not observed and the density of nerve fibers seemed to be normal as compared to the findings of control rats among the all experimental periods. Cross relationships between ERM and nerve fibers were not found histologically. In this situation, the proliferation of ERM was not recognized. In the periodontium of rats with accidentally perforated pulp floor, however, severe inflammatory responses took placed and the enlarged mass of ERM were observed at 6 weeks after the operation. This finding indicated that inflammatory factors might be responsive to the proliferation of ERM. In the cervical and bifurcational periodontium, ERM and osteoblasts were immunoreactive to TrkA. As time passed after the surgery, the immunoreactivity of both ERM and osteoblasts decreased. It was of particular interest that osteoblasts distributed on opposite site to ERM showing weak or negative TrkA immunoreactivity decreased in number and also showed weak or negative TrkA immunoreactivity. It was reported that the furcation area of molars was area at which the alveolar bone and periodontal ligament was remodeled actively. It was suggested that fibroblast-derived NGF, which was subject to receptor-mediated internalization by odontoblasts, might regulate odontoblasts. Taking these findings into consideration, TrkA-positive ERM might play important role in regulation of bone remodeling in the cervical and bifurcational periodontium.