动态压应力促进大鼠成骨细胞成熟分化的基因水平研究

A genetic study of dynamic compressive stress promoting proliferation and differentiation of rat osteoblasts

目的观察不同强度压应力刺激对大鼠成骨细胞骨桥蛋白（OPN）、核结合因子d1（Runx2）、骨钙素（OC）、Osterix、碱性磷酸酶（ALP）及骨形态发生蛋白2（BMP-2）mRNA表达的影响。方法采用酶消化法从胎鼠颅骨中提取成骨细胞，经体外扩增后采用ALP染色及茜素红染色法对纯化后的细胞进行鉴定；将所培养成骨细胞按随机数字表法分为对照组、20mmHg实验组、50mmHg实验组及100mmHg实验组，分别置于压力加载装置中给予不同强度（压应力强度分别为0、20、50和100mmHg）压应力刺激。于压应力刺激24h后采用实时定量PCR技术检测各组细胞OPN、Runx2、OC、Osterix、ALP及BMP-2mRNA表达情况。结果成骨细胞在20mmHg压应力刺激下，其OPN、Runx2、OC、BMP-2及ALPmRNA表达均较对照组明显升高（P〈0．05），OsterixmRNA表达亦较对照组增强，但组间差异无统计学意义（P〉0．05）；在50mmHg压应力刺激下，成骨细胞OPN、Runx2、OC、Osterix、BMP-2和ALPmRNA表达亦较对照组进一步增高（P〈0．05）；在100mmHg压应力刺激下，成骨细胞OPN、Runx2、OC、Osterix、BMP-2及ALPmRNA表达虽较对照组有所增强，但此时组间差异均无统计学意义（P〉0．05）。结论一定强度范围的压应力刺激能够促进成骨细胞OPN、Runx2、OC、Osterix、ALP及BMP-2mRNA表达，这可能是压应力刺激促进骨折愈合的重要机制之一。

Objective To study the impacts of dynamic compressive stress on the mRNA expression of osteopontin （OPN） ,runt related gene 2 （Runx2） ,osteocalcin （OC） ,osterix, alkaline phosphatase （ALP） and bone morphogenetic protein 2 （BMP-2） in the osteoblasts of Sprague-Dawley （SD） rats. Methods Osteoblasts extracted from skull periosteum tissue of neonatal SD rats were digested using trypsin and collagenase I, then were subcuhured and amplified in vitro. ALP staining and alizarin red staining were performed to identify the purified cells. The cells were treated with compressive stress at 20, 50 or 100 mmHg for 24 h. The expression levels of OPN, Runx-2, OC, osterix, ALP and BMP-2 were measured and quantitatively analysed using a real-time quantitative polymerase chain reaction. Results Under 20 mmHg of dynamic compressive stress the expression levels of OPN, Runx2, OC, osterix, ALP and BMP-2 all were elevated compared with the control group. The peak expression occured under 50 mmHg pressure. The expression levels did not change significantly compared with the control group under 100 mmHg pressure. Conclusions Moderate dynamic compressive stress can promote the expression of OPN, Runx-2, OC, osterix, ALP and BMP-2 mRNA in osteoblasts, which might be an important mechanism for promoting the union of fractures.