Yamaguchi Masaru, Ozawa Yasuhito, Nogimura Aki, Aihara Norihito, Kojima Tadashi, Hirayama Yoshimasa, Kasai Kazutaka
Department of Orthodontics, Nihon University School of Dentistry at Matsudo, Sakaecho-Nishi, Chiba, Japan.
Connect Tissue Res. 2004;45(3):181-9. doi: 10.1080/03008200490514149.
Cathepsin is a typical and well-characterized lysosomal cysteine protease that, under pathological conditions, is involved in tissue destruction. A recent immunocytochemical study demonstrated that cathepsins B (CAB) and L (CAL) were localized in the periodontal ligament (PDL) of the rat molar, and they were expressed in compressed sites during experimental tooth movement. Further, we demonstrated previously that the levels of CAB and CAL in gingival crevicular fluid increased during orthodontic tooth movement. Therefore, CAB and CAL may play important roles in the process of collagen degradation during orthodontic tooth movement, and our in vitro study examined the secretion of CAB and CAL in PDL cells following mechanical stress. PDL cells were subjected to 0.5, 1.0, 2.0, or 3.0 g/cm2 of compression force or an increase in surface area by tension force of 0.28%, 0.95%, 1.72%, or 2.50% for 24 hr. For detection of CAB and CAL in conditioned medium, commercially available ELISA kits were used. We found compression and tension significantly increased the secretions of both CAB and CAL in PDL cells, which were exhibited in a time- and force magnitude-dependent manner. The compression-stimulated secretion of CAB was increased approximately 3-fold and that of CAL 4-fold, as compared with the control. Further, tension-stimulated secretion of CAB was increased by 1.5-fold and that of CAL 2-fold compared with the control. When analyzed using a semiquantitative polymerase chain reaction assay, CAB and CAL mRNA were increased in response to both compression and tension forces. These findings demonstrated that mechanical stress (compression and tension forces) causes an increase in secretion of CAB and CAL in PDL cells in vitro.
组织蛋白酶是一种典型的、特征明确的溶酶体半胱氨酸蛋白酶，在病理条件下参与组织破坏。最近的一项免疫细胞化学研究表明，组织蛋白酶B（CAB）和L（CAL）定位于大鼠磨牙的牙周韧带（PDL）中，并且在实验性牙齿移动过程中它们在受压部位表达。此外，我们先前证明，在正畸牙齿移动过程中龈沟液中CAB和CAL的水平会升高。因此，CAB和CAL可能在正畸牙齿移动过程中的胶原降解过程中起重要作用，并且我们的体外研究检测了机械应力作用下PDL细胞中CAB和CAL的分泌情况。将PDL细胞分别施加0.5、1.0、2.0或3.0 g/cm²的压力，或分别施加0.28%、0.95%、1.72%或2.50%的张力以增加表面积，持续作用24小时。使用市售的ELISA试剂盒检测条件培养基中的CAB和CAL。我们发现压力和张力均显著增加了PDL细胞中CAB和CAL的分泌，且呈时间和力大小依赖性。与对照组相比，压力刺激下CAB的分泌增加了约3倍，CAL的分泌增加了4倍。此外，与对照组相比，张力刺激下CAB的分泌增加了1.5倍，CAL的分泌增加了2倍。当使用半定量聚合酶链反应分析时，CAB和CAL mRNA在压力和张力作用下均增加。这些发现表明，机械应力（压力和张力）在体外可导致PDL细胞中CAB和CAL的分泌增加。
