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A study on the morphological changes of osteocytes in rat alveolar bone during orthodontic tooth movement

正畸牙移动过程中大鼠牙槽骨骨细胞形态变化的研究

基本信息

批准号：
08672356
负责人：
IGARASHI Kaoru
金额：
$ 1.47万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

项目摘要

The purposes of the present study were 1) to examine the morphological changes of osteocytes in rat alveolar bone during orthodontic tooth movement using immunohistochemistry for actin filaments and 2) to determine a molecular marker for osteocyte metabolism. Eight-week-old male Wistar rats were used in this study. The maxillary first molars were moved buccally by using a expansive spring of Ni-Ti wire with a nominal size of 0.012 inch as described by Igarashi et al. (1998). The animals were killed after 3, 6, 12, 24 hours, 2, 4, 7, 10 and 14 days of tooth movement. After experiments, the animals were fixed with 4 % paraformaldehyde plus 0.5 % glutaraldehyde in 0.1 M PB, pH 7.4, decalcified with 10 % EDTA solution and processed into paraffin embedding. Six-mu in-thick sections were stained with hematoxilin-eosin or antibodies for osteocalcin, typesI,II and X collagen and actin filaments. The results were as follows ;1) Precursor and mature osteocalcin was a proper molecular marker for examining the metabolic changes of alveolar bone and bone-forming cells.2) After 3 hours of orthodontic tooth movement, hyaline tissue appeared in the pressure side of the periodontal tissue of all five roots of the first molar. The hyaline tissue spread and almost dessapered at day 10.3) Immunohistochemistry for actin filament showed intense staining in cytoplasm and cellular processes of osteocytes in control group. Especially young osteocytes showed intense staining. In contrast, the staining of osteocyte cytoplasm adjacent to the hyaline tissue became weak at day 1 and the staining of its cellular processes disappeared at day 4.These results demonstrated that osteocytes adjacent to the hyaline degeneration tissue became cell death during early stage of orthodontic tooth movement due to the disappearance of intercellular communication between the periodontal tissue cells.

本研究的目的是：1）使用肌动蛋白丝的免疫组织化学方法检测大鼠正畸牙齿移动过程中牙槽骨中骨细胞的形态学变化; 2）确定骨细胞代谢的分子标志物。本研究使用8周龄雄性Wistar大鼠。如Igarashi等人（1998）所述，使用标称尺寸为0.012英寸的镍钛丝膨胀弹簧，将上颌第一磨牙向颊侧移动。在牙齿移动3、6、12、24小时、2、4、7、10和14天后处死动物。实验结束后，动物用4%多聚甲醛加0.5%戊二醛的0.1 M PB（pH 7.4）溶液固定，用10%EDTA溶液脱钙并进行石蜡包埋。6 μ m厚的切片用苏木精-伊红或骨钙素、I型、II型和X型胶原和肌动蛋白丝的抗体染色。结果表明：（1）前体骨钙素和成熟骨钙素是检测牙槽骨和骨形成细胞代谢变化的合适分子标志物;（2）正畸牙移动3 h后，第一磨牙5个牙根的牙周组织压力侧均出现透明组织。3）对照组骨细胞肌动蛋白纤维免疫组化染色显示，肌动蛋白纤维在骨细胞的胞浆和胞突中呈强阳性染色。特别是年轻的骨细胞显示出强烈的染色。与玻璃样变组织相邻的骨细胞胞质在第1天染色减弱，其细胞突起在第4天染色消失。这些结果表明，在正畸牙移动早期，由于牙周组织细胞间通讯的消失，玻璃样变组织相邻的骨细胞发生了细胞死亡。