Liu Jun, Zhao Zhihe, Zou Ling, Li Juan, Wang Fengming, Li Xiaoyu, Zhang Jingyi, Liu Yurong, Chen Sixiu, Zhi Maohui, Wang Jun
State Key Laboratory of Oral Diseases, West China College of Stomatology, West China Hospital of Stomatology, Sichuan University, 14#, 3rd section, Renmin South Road, Chengdu 610041, China.
Ann Biomed Eng. 2009 Apr;37(4):794-802. doi: 10.1007/s10439-009-9638-9. Epub 2009 Jan 14.
Mechanical stress plays an important role in bone remodeling. However, it is still unclear whether mechanical stress regulates osteoclastogenesis mediated by mesenchymal stem cells (MSCs) during initial osteodifferentiation. We investigated the effects of static and dynamic pressures on osteoclast-inducing potential of MSCs during early osteodifferentiation. The osteoclastogenesis was examined using TRAP staining. The mRNA levels of receptor activator of nuclear factor-kappaB ligand (RANKL) and osteoprotegerin (OPG) genes were analyzed using real-time RT-PCR. It was shown that MSCs exposed to either pressure during initial osteodifferentiation promoted osteoclastogenesis with the up-regulation of RANKL/OPG ratio. MSCs displayed diverse responses to pressures at different points of initial osteodifferentiation. The RANKL/OPG ratio was significantly increased after osteoinduction in the primary MSCs without pressures exposure, which contradicted the previous report. These results suggest novel mechanisms of the initial biological responses of bone remodeling upon mechanical stimuli.
机械应力在骨重塑中起着重要作用。然而，在初始骨分化过程中，机械应力是否调节间充质干细胞（MSCs）介导的破骨细胞生成仍不清楚。我们研究了静态和动态压力对早期骨分化过程中MSCs诱导破骨细胞生成潜能的影响。使用抗酒石酸酸性磷酸酶（TRAP）染色检测破骨细胞生成。使用实时逆转录聚合酶链反应（RT-PCR）分析核因子κB受体活化因子配体（RANKL）和骨保护素（OPG）基因的mRNA水平。结果表明，在初始骨分化过程中暴露于任何一种压力下的MSCs均通过上调RANKL/OPG比值促进破骨细胞生成。MSCs在初始骨分化的不同时间点对压力表现出不同的反应。在未暴露于压力的原代MSCs中，骨诱导后RANKL/OPG比值显著增加，这与之前的报道相矛盾。这些结果提示了机械刺激后骨重塑初始生物学反应的新机制。
