不同加载频率及力值的循环张应力对大鼠颅底软骨细胞的影响

目的 构建颅底软骨细胞体外培养力学模型，研究不同条件循环张应力（cyclic tensile strain, CTS）对颅底软骨细胞的影响。方法 采用FX-5000T应力加载系统对体外培养的第2代大鼠颅底软骨细胞施加不同条件的循环张应力，加力大小分别为5%、10%延伸率，加力频率分别为0.3、0.5、1.0 Hz，加力时间为24 h。加力后即刻收集细胞，提取总RNA，实时荧光定量PCR检测颅底软骨细胞Ⅱ型胶原(type-Ⅱcollagen,Col-Ⅱ)和Sox9 mRNA的表达。数据采用SPSS 17.0软件包进行统计学分析。结果 循环张应力大小为10%延伸率、频率为0.5 Hz或1.0 Hz时可显著促进大鼠颅底软骨细胞Col-Ⅱ及Sox9表达（P<0.05）。结论 适宜条件的循环张应力可促进大鼠颅底软骨细胞基质合成。

Effects of cyclic tensile stress with different frequencies and elongation rates on rat cranial base synchondrosis chondrocytes

Objective To establish an in vitro mechanical stimulation model of cranial base synchondrosis chondrocytes and to explore the effects of cyclic tensile strain(CTS) with different frequencies and elongation rates on cranial base synchondrosis chondrocytes.Methods Cyclic tensile stress was imposed to the second passage of cranial base synchondrosis chondrocytes by Flexcell Strain Unit-5000 T.The elongation rates were 5% or 10%.The frequencies applied were 0.3,0.5 or 1.0 Hz.The stress application time was 24 h.After mechanical loading,total RNA of the cells harvested from six-well BioFlex was extracted.Real-time quantitative RT-PCR was performed to quantify the mRNA levels of type Ⅱ collagen and Sox9.The data were statistically analyzed with SPSS 17.0.Results Compared with the control group,the mRNA expression of Col-Ⅱ and Sox9 increased significantly(P<0.05) when elongation rate was 10% and frequency was 0.5 or 1.0 Hz.Conclusions Cyclic tensile stress with appropriate frequency and elongation rate can promote the synthesis of extracellular matrix of cranial base synchondrosis in vitro.