动态压应力对生长板软骨前体干细胞PTHrP及细胞外基质mRNA表达的影响

The effect of dynamic compressive force on the mRNA expression of parathyroid hormone-related peptide and extracellular matrix of rat precartilaginous stem cells

目的 研究动态压应力对体外培养的大鼠生长板软骨前体干细胞甲状旁腺激素相关肽（PTHrP）以及软骨特性细胞外基质mRNA表达的影响.方法 免疫磁珠分选并体外培养大鼠软骨前体干细胞,用自行设计制作的可控细胞压力加载装置对细胞进行不同强度（30 mmHg、60 mmHg、90mmHg）和持续时间（1 h、6 h、24 h）的压应力刺激,未刺激组为对照组,采用逆转录-聚合酶链反应（RT-PCR）技术分别检测各组细胞的PTHrP以及软骨特性细胞外基质（Ⅱ型胶原、X型胶原以及aggreean）mRNA表达并进行半定量分析.结果 生长板软骨前体干细胞在30 mmHg、60 mmHg、90 mmHg动态压力培养环境下,各时间点PTHrP、Ⅱ型胶原以及aggrecan mRNA表达水平明显增强并高于对照组（P〈0.05）;Ⅱ型胶原以及aggrecan mRNA表达水平于6h达高峰,PTHrP mRNA的表达水平随时间增加而增强,24 h仍有较高水平的表达;且压力值越大,相同时间点mRNA相对表达量越高.X型胶原表达水平较低且与对照组比较差异无统计学意义（P〉0.05）.结论 适当的动态压应力能有效促进体外培养的大鼠软骨前体干细胞Ⅱ型胶原及aggreean mRNA表达,PTHrP在此力学信号转导过程中可能起重要的作用.

Objective To investigate the impact of dynamic compressive force on the mRNA expression of parathyroid hormone-related peptide（PTHrP）and chondrogenic extraeellular matrix in rat precartilaginous stem cells（PSCs）.Methods The rat PSCs were isolated and purified using magnetic activated cell sorting and cultured in vitro.The cells were subjected to different intensities of compressive pressure of 30 mmHg,60 mmHg,90 mm Hg for 1 h,6 h,and 24 h. The expression levels of type Ⅱcollagen,type X collagen and aggrecan,and PTHrP were measured by reverse transcription polymerase chain reaction（RT-PCR）.Results Under dynamic compressive pressures,the expression levels of type Ⅱ collagen,aggrecan and PTHrP increased significantly compared with the control groups at all endpoints（P〈0.05）;however,the expression levels of type X collagen did not change significantly （P〉0.05）.The peak expression of type Ⅱ collagen,aggrecan mRNA occurred after 6 hours＇stimulation.The expression of PTHrP increased continuously from 1 to 24 hours.Conclusions Moderate dynamic compressive force promotes the expression levels of type Ⅱ collagen,aggrecan mRNA in rat PSCs in vitro,indicating PTHrP could be an important mediator in biomechanical signal transduction pathway.