SPECIFIC RESPONSES OF HUMAN MANDIBULAR OSTEOCYTE TO MECHANICAL LOADING

1999年：今年的计划是比较下颌骨细胞和股骨骨细胞对拉伸的反应。但我们得到了一个有趣的结果来表征下颌骨细胞对拉伸和甲状旁腺激素的反应，因此我们报道了(B.B.R.C卷264)。2000：为了比较下颌骨细胞和股骨骨细胞的反应，我们准备了两种机械加载方法。一种是利用换能器--Sonic Accelerated骨折愈合系统(SAFHS，Exogen，Inc.)产生的低强度脉冲超声波。最近我们报道了(B.B.R，C卷268)，另一种是Flexercell菌株单位(Flexpercell Corp.)已经报告(内分泌学第137卷和B.B.R.C.第246卷)。两者都已经放置在神奈川牙科拼贴上。)1，人骨细胞培养(J.bone Miner.Res.Vol.10和Calcif.组织Int.Vol.57)2，骨细胞到机械负荷(1999年)拉伸(内分泌学卷137和B.R.C.Vol.246)，以及甲状旁腺素(1-34)…(2000)加入低强度脉冲超声(B.B.R.C.Vol.268)和甲状旁腺素(1-34)。在1，0min(对照)；2，15min；3，Ihr，5，6小时；6，24小时收集的细胞总RNA样本的每组6个样本用引物(GAPDH，骨钙素，碱性磷酸酶，IGF-1，COX-2等)进行PCR分析(J.bone Miner.Res.Vol.10和Calcif.TIssueInt.57)。我们使用该助学金支持的Thamal Cycler进行RT-PCR分析。3，结果和讨论(1999)在PTH的存在下(在拉伸开始后1小时)，骨钙素mRNA的稳态水平进一步上调。另一方面，在PTH存在的情况下(在3h拉伸后的3h)，消息的下调水平进一步下调(B.B.R.C.Vol.264)。在应对过程中，协同作用可以是积极的，也可以是消极的。由此，我们推测PTH信号通路和拉伸激活的机械转导通路之间存在相关机制。(2000)我们研究了低强度脉冲超声波对骨髓基质来源的ST2细胞的影响。他们对超声波的反应是IGF mRNAs、骨钙素和骨质疏松蛋白mRNAs水平升高。这些信息的上调表达以双相方式出现(B.B.R.C.Vol.268)。相反，在股骨中分离的骨细胞中，超声波不能有效地诱导成骨细胞的合成代谢反应。但最近我们得到了一个新的结果，可以有效地引导骨基质的形成，现在我们对这个结果进行了讨论，还需要尽快在其他样本中进行更多的研究。4、结论我们的结果表明，下颌骨神经峰骨细胞对来自股骨的机械载荷的反应是不同的，我们需要更多的研究来获得良好的骨再生手术，如口腔颌面部破坏性成骨。较少

1999 : The schedule of this year is to compare the response of mandibular osteocytes with femoral one to stretching.But we obtained an interesting result to charactorise the response of mandibular osteocytes to stretching and parathyroid hormone, (1-34) PTH.So we reported (B.B.R.C vol.264).2000 : Concerning to the comparison the response of mandibular osteocytes with femoral, we prepared two way of mechanical loading procedures. One is the low-intensity pulsed ultrasound which is generated with the transducer, the Sonic Accelerated Fracture Healing System (SAFHS, Exogen, Inc.) recently we reported (B.B.R,C vol.268), the other is Flexercell Strain Unit (Flexercell Corp.) already reported (Endocrinology vol.137 and B.B.R.C.vol.246). Both are already placed on Kanagawa Dental Collage.)1, Human osteocytic cell culture (J.Bone Miner.Res.vol.10 and Calcif. Tissue Int.vol.57)2, Osteocytic cells to mechanical loading(1999) Stretching (Endocrinology vol.137 and B.B.R.C.vol.246), and PTH (1-34) … More was added.(2000) Low-intensity pulsed ultrasound (B.B.R.C.vol.268), and PTH (1-34) was added.Each set of six total RNA samples from the cells harvested at : 1, 0 min (control) ; 2, 15 min ; 3, Ihr, 5, 6 hrs ; 6, 24 hrs were subjected to PCR analysis with primers (GAPDH, Osteocalcin, ALP, IGF-1, COX-2, et al.)(J.Bone Miner.Res.vol.10 and Calcif.Tissue Int.vol.57). We used the Thamal Cycler which was supported by this grants-in-aid to do RT-PCR analysis.3, Result and Discussion(1999) The upregulated steady-state level of osteocalcin mRNA is further upregulated in the presence of PTH (at 1 h after the initiation of stretching). On the other hand, the downregulated level of the message is further downregulated in the presence of PTH (at 3 h after the 3-h stretching)(B.B.R.C.vol.264). The synergy can be either way, positive or negative, in the course of the response. From this, we presume that related mechanisms are at work between the PTH signaling pathways and the mechanotransduction pathways activated by Stretching.(2000) The effects of 20-min exposure to low-intensity, pulsed ultrasound were investigated in ST2 cells of bone marrow stromal origin. They responded to ultrasound with elevated levels of IGF mRNAs, osteocalcin, and bone sia-loprotein mRNAs. The upregulated expression of these messages appeared in a biphasic manner (B.B.R.C.vol.268). On the contrary, in osteocytes hervested from femoral bone, ultrasound was not effective to induce an anabolic reaction of osteogenic cells. But recently we obtained a new result that was effective to lead bone matrix formation, now we discuss this results and have to investigate more in other samples as soon as possible.4, ConclusionOur result suggest that Mandibular osteocytes from neural crests show diferent response to mechanical loading from femoral bone, we need more investigations to obtein good result in bone regenerative operations such as distruction osteogenesis in oral and maxillofacial area. Less