Optimal compressive force induces bone formation via increasing bone morphogenetic proteins production and decreasing their antagonists production by Saos-2 cells

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• 作者：Narihiro Mitsui ; Naoto Suzuki ; Masao Maeno ; Momoko Yanagisawa ; Yuki Koyama ; Kichibee Otsuka and Noriyoshi Shimizu
• 关键词：Mechanical stress ; Osteoblasts ; Mineralization ; BMPs ; BMP antagonist
• 刊名：Life Sciences
• 出版年：2006
• 出版时间：1 May 2006
• 年：2006
• 卷：78
• 期：23
• 页码：2697-2706
• 全文大小：688 K

文摘

Orthodontic tooth movement induced alveolar bone resorption and formation around the teeth applied mechanical force. Although mechanical force can promote bone formation, the molecular mechanism that underlies this phenomenon is not fully understood. The purposes of this study were to determine how mechanical stress affects the osteogenic response of human osteoblastic cells (Saos-2), and also to examine the optimal compressive force for osteogenesis in vitro. Saos-2 cells were cultured with or without continuously compressive force (0.5–3.0 g/cm²). The expression of bone morphogenetic proteins (BMPs), their antagonists, and transcription factors which involved in osteogenesis were measured using real-time PCR and/or Western blot analysis. Phosphorylation of Smad1 was determined by Western blot. Loading with 1.0 g/cm² of compressive force significantly increased the expression of BMPs, Runx2 and osterix. In contrast, the expression of BMP antagonists and AJ18 was decreased with 1.0 g/cm² of compressive force. Loading with 1.0 g/cm² of compressive force also induced phosphorylation of Smad1. Noggin inhibited the compressive force-induced phosphorylation of Smad1 markedly, and also partially blocked compressive force-induced Runx2 mRNA expression. Moreover, the conditioned medium from 1.0 g/cm² of compressive force applied cells apparently increased calcium content in mineralized nodules of Saos-2 culture. This study demonstrates that an optimal compressive force stimulates in vitro mineralization via increasing BMPs production and decreasing their antagonists production.