Department of Mechanical Engineering POSTECH Pohang 790-751, Korea.
Exp Mol Med. 2011 Jun 30;43(6):367-73. doi: 10.3858/emm.2011.43.6.040.
We observed how combined mechanical stimuli affect the proliferation and differentiation of pre-osteoblasts. For this research, a bioreactor system was developed that can simultaneously stimulate cells with cyclic strain and ultrasound, each of which is known to effectively stimulate bone tissue regeneration. MC3T3-E1 pre-osteoblasts were chosen for bone tissue engineering due to their osteoblast-like characteristics. 3-D scaffolds were fabricated with polycaprolactone and poly-L-lactic acid using the salt leaching method. The cells were stimulated by the bioreactor with cyclic strain and ultrasound. The bioreactor was set at a frequency of 1.0 Hz and 10 % strain for cyclic strain and 1.0 MHz and 30 mW/cm(2) for ultrasound. Three experimental groups (ultrasound, cyclic strain, and combined stimulation) and a control group were examined. Each group was stimulated for 20 min/day. Mechanical stimuli did not affect MC3T3-E1 cell proliferation significantly up to 10 days when measured with the cell counting kit-8. However, gene expression analysis of collagen type-I, osteocalcin, RUNX2, and osterix revealed that the combined mechanical stimulation accelerated the matrix maturation of MC3T3-E1 cells. These results indicate that the combined mechanical stimulation can enhance the differentiation of pre-osteoblasts more efficiently than simple stimuli, in spite of no effect on cell proliferation.
我们观察了联合机械刺激如何影响前成骨细胞的增殖和分化。为此研究开发了一种生物反应器系统，该系统可以同时用循环应变和超声波刺激细胞，这两种刺激都已知能有效地刺激骨组织再生。由于具有成骨细胞样的特征，因此选择 MC3T3-E1 前成骨细胞用于骨组织工程。使用盐浸出法用聚己内酯和聚 L-乳酸制造 3-D 支架。用生物反应器用循环应变和超声波刺激细胞。生物反应器的循环应变设置为 1.0 Hz 和 10％应变，超声波设置为 1.0 MHz 和 30 mW/cm(2)。检查了三个实验组（超声组、循环应变组和联合刺激组）和一个对照组。每组每天刺激 20 分钟。用细胞计数试剂盒-8 测量时，机械刺激在前 10 天对 MC3T3-E1 细胞增殖没有明显影响。然而，对胶原蛋白 I、骨钙素、RUNX2 和 osterix 的基因表达分析表明，联合机械刺激加速了 MC3T3-E1 细胞的基质成熟。这些结果表明，尽管对细胞增殖没有影响，但联合机械刺激可以比简单刺激更有效地促进前成骨细胞的分化。
