Green D D, Hembry R M, Atkinson S J, Reynolds J J, Meikle M C
Department of Orthodontics, Eastman Dental Hospital, London, England.
Am J Orthod Dentofacial Orthop. 1990 Apr;97(4):281-8. doi: 10.1016/0889-5406(90)70100-Q.
To investigate the effects of mechanical deformation on matrix degradation in fibrous joints, coronal suture explants from neonatal rabbits were stressed in vitro for 24 hours in an established tooth-movement model system. The metalloproteinase collagenase (CL) and its inhibitor, TIMP (tissue inhibitor of metalloproteinases), were immunolocalized in two ways by a two-step indirect technique: (1) extracellularly by immunoprecipitation at the site of secretion, and (2) intracellularly by incubation of the explants with the ionophore monensin. Immunoprecipitates of CL and TIMP were distributed throughout the sutural and periosteal tissues of nonstressed explants. In stressed explants, however, CL immunoprecipitates were predominantly associated with an area of rounded cells between the bone ends. In explants treated with monensin a significant increase in the number of CL-positive cells was observed in this cellular area; active enzyme was suggested by the demonstration of CL bound to collagen. Extracellular TIMP was not seen within the area of rounded cells of stressed explants, but intracellular TIMP was detectable; this suggests that insufficient TIMP was available to immunoprecipitate with anti-TIMP, probably because it had become irreversibly complexed with active CL. Since the area of rounded cells corresponds to the site of increased cell proliferation in this and other animal models of tooth movement, these data suggest that collagenase production and cell proliferation might be correlated. We speculate that matrix degradation is an essential prerequisite for cell proliferation as it creates room to accommodate an increase in cell population.
为研究机械变形对纤维性关节中基质降解的影响，在已建立的牙齿移动模型系统中，对新生兔的冠状缝外植体进行了24小时的体外应力加载。金属蛋白酶胶原酶（CL）及其抑制剂金属蛋白酶组织抑制剂（TIMP）通过两步间接技术以两种方式进行免疫定位：（1）通过在分泌部位进行免疫沉淀在细胞外定位，以及（2）通过将外植体与离子载体莫能菌素孵育在细胞内定位。CL和TIMP的免疫沉淀物分布在未受应力外植体的缝线和骨膜组织中。然而，在受应力的外植体中，CL免疫沉淀物主要与骨端之间的圆形细胞区域相关。在用莫能菌素处理的外植体中，在该细胞区域观察到CL阳性细胞数量显著增加；与胶原结合的CL的显示表明存在活性酶。在受应力外植体的圆形细胞区域内未观察到细胞外TIMP，但可检测到细胞内TIMP；这表明没有足够的TIMP可与抗TIMP进行免疫沉淀，可能是因为它已与活性CL形成不可逆的复合物。由于在该牙齿移动动物模型以及其他动物模型中，圆形细胞区域对应于细胞增殖增加的部位，这些数据表明胶原酶的产生与细胞增殖可能相关。我们推测基质降解是细胞增殖的必要前提，因为它为细胞数量的增加创造了空间。
