Department of Orthopedic and Spinal Surgery, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, China.
Int J Med Sci. 2012;9(9):801-7. doi: 10.7150/ijms.4838. Epub 2012 Oct 26.
Osteoclasts are the key participants in regulation of bone mass. Low-magnitude high-frequency vibration (LMHFV) has been found to be anabolic to bone in vivo. This study aimed to investigate the effect of LMHFV on osteoclast differentiation in vitro. Murine monocyte cell line RAW264.7 cells in the presence of receptor activator of nuclear factor-kappaB ligand (RANKL) were treated with or without LMHFV at 45 Hz (0.3 g) for 15 min day(-1). Tartrate resistant acid phosphatase (TRAP)-positive multinucleated cells (MNCs) and actin ring formation were evaluated. Expression of the osteoclast-specific genes, such as cathepsin K, matrix metallopeptidase-9 (MMP-9) and TRAP, were analyzed using real time-PCR. c-Fos, an osteoclast-specific transcription factor, was determined using Western blot. We found that LMHFV significantly decreased the number of RANKL-induced TRAP-positive MNCs (P<0.01), and inhibited the actin ring formation. The mRNA expression of the cathepsin K, MMP-9 and TRAP were down-regulated by LMHFV intervention (all P<0.001). Furthermore, LMHFV also inhibited the expression of c-Fos protein in the RANKL-treated RAW264.7 cells (P<0.05). Our results suggest that LMHFV can inhibit the RANKL-induced osteoclast differentiation of RAW264.7 cells, which give some new insight into the anabolic effects of LMHFV on bone.
破骨细胞是调节骨量的关键参与者。已经发现低幅度高频振动（LMHFV）对体内骨骼具有合成代谢作用。本研究旨在探讨 LMHFV 对体外破骨细胞分化的影响。用核因子-κB 受体激活剂配体（RANKL）处理小鼠单核细胞系 RAW264.7 细胞，然后用或不用 45 Hz（0.3 g）的 LMHFV 每天处理 15 分钟。评估抗酒石酸酸性磷酸酶（TRAP）阳性多核细胞（MNC）和肌动蛋白环形成。使用实时 PCR 分析破骨细胞特异性基因，如组织蛋白酶 K、基质金属蛋白酶-9（MMP-9）和 TRAP 的表达。使用 Western blot 测定破骨细胞特异性转录因子 c-Fos。我们发现，LMHFV 显著降低了 RANKL 诱导的 TRAP 阳性 MNC 的数量（P<0.01），并抑制了肌动蛋白环的形成。LMHFV 干预还下调了组织蛋白酶 K、MMP-9 和 TRAP 的 mRNA 表达（均 P<0.001）。此外，LMHFV 还抑制了 RANKL 处理的 RAW264.7 细胞中 c-Fos 蛋白的表达（P<0.05）。我们的结果表明，LMHFV 可以抑制 RANKL 诱导的 RAW264.7 细胞破骨细胞分化，这为 LMHFV 对骨骼的合成代谢作用提供了一些新的见解。
