Mechanical stress directly suppresses osteoclast differentiation in RAW264.7 cells.
Mechanical stress directly suppresses osteoclast differentiation in RAW264.7 cells.
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DOI：
10.3892/ijmm.21.3.291
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发表时间：
2008-03
影响因子：
5.4
通讯作者：
Nobumitsu Suzuki;Y. Yoshimura;Y. Deyama;Kuniaki Suzuki;Y. Kitagawa
中科院分区：
文献类型：
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作者：
Nobumitsu Suzuki;Y. Yoshimura;Y. Deyama;Kuniaki Suzuki;Y. Kitagawa
尽管已知机械应力对成骨细胞和牙周膜细胞的作用会抑制破骨细胞的分化，但对机械应力对破骨细胞分化的直接影响知之甚少。在这项研究中，我们研究了机械应力对破骨细胞分化的作用，使用核因子-κ B配体受体激活剂（RANKL）处理的小鼠前骨肉瘤RAW 264.7细胞。将RAW细胞与RANKL一起培养，并施加机械应力一段时间。我们计数了抗酒石酸酸性磷酸酶（TRAP）阳性和多核（2个核或更多）的破骨细胞的数量，并通过RT-PCR测量mRNA。有一个机械应力下的破骨细胞的数量减少相比，没有机械应力下的数量。与施加机械应力培养的破骨细胞的细胞核数量相比，每个破骨细胞的细胞核数量也减少了。当细胞培养1-7天和/或施加机械应力的不同时间段时，破骨细胞的分化随着机械应力的增加而减少，而在去除机械应力后增加。破骨细胞特异性基因TRAP、基质金属蛋白酶-9、组织蛋白酶-K和降钙素受体的mRNA表达随机械应力而降低，并与破骨细胞的数量相关。抑制破骨细胞分化的诱导型一氧化氮合酶mRNA随着机械应力的增加而增加。尽管破骨细胞的数量减少与机械应力，活化T细胞胞质核因子1（NFATc 1）和NFATc 2 mRNA的表达增加与机械应力。这些发现表明，机械应力直接抑制破骨细胞分化，并增加NFATc 1和NFATc 2表明延迟分化。
Although it is known that mechanical stress to osteoblast and periodontal ligament cells suppresses osteoclast differentiation, little is known about the direct effect of mechanical stress on osteoclast differentiation. In this study, we examined the role of mechanical stress on osteoclast differentiation using murine pre-osteoclastic RAW264.7 cells treated with receptor activator of nuclear factor-kappaB ligand (RANKL). RAW cells were cultured with RANKL, and mechanical stress was applied for a given period. We counted the number of osteoclast cells which were tartrate-resistant acid phosphatase (TRAP)-positive and multinucleated (2 nuclei or more), and measured mRNA by RT-PCR. There was a decrease in the number of osteoclasts under mechanical stress compared with the number under no mechanical stress. The number of nuclei per osteoclast also decreased compared to the number of nuclei per osteoclast cultured with the application of mechanical stress. As the cells were cultured for a period of 1-7 days and/or for different periods of mechanical stress application, osteoclast differentiation decreased with mechanical stress and increased after removing mechanical stress. Expression of mRNA for the osteoclast-specific genes, TRAP, matrix metalloproteinase-9, cathepsin-K and calcitonin receptor, decreased with mechanical stress and was associated with the number of osteoclasts. Inducible nitric oxide synthase mRNA which inhibits osteoclast differentiation, increased with mechanical stress. In spite of the decrease in osteoclast number with mechanical stress, nuclear factor of activated T cell cytoplasmic 1 (NFATc1) and NFATc2 mRNA expression increased with mechanical stress. These findings indicate that mechanical stress directly suppresses osteoclast differentiation and increases NFATc1 and NFATc2 suggesting delayed differentiation.