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Mechanoreceptors in Alveolar Osteocyte

肺泡骨细胞中的机械感受器

基本信息

批准号：
07838043
负责人：
TAKAGAKI Yuko
金额：
$ 1.47万
依托单位：
Kanagawa Dental College
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07838043/
关键词：
osteocyte mechanical stress alveolar bone stretchig proliferation development bone formation 骨形成

项目摘要

Although it is well known that bone formation is accelerated by mechanical stimuli, the signal transduction pathways involved are largely unknown. Suggested by the studies by E.Burger and others, which showed that bone cells respond to high-level and low-level stresses differently, we compared the response of newborn rat calvarial cells to mechanical stress during their development from immature osteoblasts to mature osteoblasts, further into osteocytes. We showed that the type of cells which is most sensitive to physiological stretching of less than 4,0000 mustrain is not osteoblast but young osteocyte. These cells are in transition from osteoblasts to osteocytes expressing low-level alkaline phosphatase and high-level osteocalcin. They also develop extensive cell processes which form a network of cells in bone. These young osteocytes stop proliferation in response to stretching and mineralize thir matrix. It was shown that cAMP is secreted and the expression of IGF-I and osteocalcin is induced in response to the stress.In human alveolar bone, it was not easy to clean the bone chips prior to the isolation of cells. That is probably why we could not obtain as many differentiated osteocytes as in rat calvaria. In those few successful cases, however, the response of osteocytes to the above mentioned stretching was similar to that of rat osteocytes. In other words, it was shown by RT-PCR method that osteocalcin expression was upregulated as a result of stretching. It was also suggested that amiloride sensitive channel (s) is involved in their response to stretching from our results of channel blocker studies measuringCa influx upon the exposure to lower osmotic conditions.

虽然众所周知，骨形成是由机械刺激加速，涉及的信号转导途径在很大程度上是未知的。根据E.Burger等人的研究表明，骨细胞对高水平和低水平应力的反应不同，我们比较了新生大鼠颅骨细胞从未成熟成骨细胞发育到成熟成骨细胞，再发育成骨细胞过程中对机械应力的反应。我们发现，对小于4,0000 μ应变的生理拉伸最敏感的细胞类型不是成骨细胞，而是年轻的骨细胞。这些细胞从成骨细胞向表达低水平碱性磷酸酶和高水平骨钙素的骨细胞过渡。它们还发育出广泛的细胞突起，形成骨骼中的细胞网络。这些年轻的骨细胞停止增殖以响应拉伸并矿化其基质。结果表明，在应力作用下，人牙槽骨细胞分泌cAMP，并诱导IGF-Ⅰ和骨钙素的表达。这可能是为什么我们不能获得尽可能多的分化成骨细胞在大鼠颅骨。然而，在这些少数成功的情况下，骨细胞对上述拉伸的反应与大鼠骨细胞的反应相似。也就是说，通过RT-PCR方法显示，骨钙素的表达作为牵拉的结果而上调。我们的通道阻断剂研究结果表明，在低渗透压条件下，阿米洛利敏感通道参与了对拉伸的反应。