State Key Laboratory of Oral Biomedical Engineering, Sichuan University, China.
Arch Med Sci. 2012 Jul 4;8(3):422-30. doi: 10.5114/aoms.2012.28810.
As one group of periodontal ligament (PDL) cells, human periodontal ligament stem cells (hPDLSCs) have been isolated and identified as mesenchymal adult stem cells (MSCs) since 2004. It has been well accepted that PDL sensitively mediates the transmission of stress stimuli to the alveolar bone for periodontal tissue remolding. Besides, the direction of MSCs differentiation has been verified regulated by mechanical signals. Therefore, we hypothesized that tensile strain might act on hPDLSCs differentiation, and the early response to mechanical stress should be investigated.
The hPDLSCs were cultured in vitro and isolated via a magnetic activated CD146 cell sorting system. After investigation of surface markers and other experiments for identification, hPDLSCs were subjected to cyclic tensile strain at 3,000 µstrain for 3 h, 6 h, 12 h, and 24 h, without addition of osteogenic supplements. In the control groups, the cells were cultured in similar conditions without mechanical stimulation. Then osteogenic related genes and proteins were analyzed by RT-PCR and western blot.
Cyclic tensile strain at 3,000 µstrain of 6 h, 12 h, and 24 h durations significantly increased mRNA and protein expressions of Satb2, Runx2, and Osx, which were not affected in unloaded hPDLSCs.
We indicate that hPDLSCs might be sensitive to cyclic tensile strain. The significant increase of Runx2, Osx and Satb2 expressions may suggest an early response toward osteogenic orientation of hPDLSCs.
自 2004 年以来，作为牙周韧带（PDL）细胞的一组，人牙周韧带干细胞（hPDLSCs）已被分离和鉴定为间充质成体干细胞（MSCs）。人们普遍认为，PDL 敏感地介导了将应力刺激传递到牙槽骨以重塑牙周组织。此外，MSCs 分化的方向已被证明受机械信号调节。因此，我们假设拉伸应变可能作用于 hPDLSCs 的分化，并且应该研究对机械应激的早期反应。
hPDLSCs 在体外培养并通过磁激活 CD146 细胞分选系统分离。在进行表面标志物等鉴定实验后，将 hPDLSCs 用 3000µstrain 的循环拉伸应变刺激 3、6、12 和 24 小时，而不添加成骨补充剂。在对照组中，细胞在类似的无机械刺激的条件下培养。然后通过 RT-PCR 和 Western blot 分析成骨相关基因和蛋白。
3000µstrain 拉伸应变 6、12 和 24 小时的循环拉伸应变显著增加了 Satb2、Runx2 和 Osx 的 mRNA 和蛋白表达，而未负载的 hPDLSCs 中则不受影响。
我们表明 hPDLSCs 可能对循环拉伸应变敏感。Runx2、Osx 和 Satb2 表达的显著增加可能表明 hPDLSCs 向成骨方向的早期反应。
