中文摘要：

目的研究基底拉伸应变对小鼠成骨细胞系MC3T3-E1细胞Runx2表达的影响。方法 实验随机分为0με、100με、1500με、2000με、2500με、5000με六组，采用卫生装备研究所自行研制的细胞基底应变加载装置对细胞进行加载，Western blot检测不同应变对成骨细胞Runx2蛋白表达的影响。此外采用Real-time PCR检测0με、2500με、5000με三种强度应变对成骨细胞Runx2m RNA表达的影响。结果Western blot结果显示：1500με、2000με、2500με组与0με组相比Runx2蛋白表达显著增强（P〈0．01）；5000με组与0με组相比Runx2蛋白表达显著降低（P〈0．01）；Real-timePCR结果显示：2500με组与0με组相比Runx2m RNA表达显著降低（P〈0．01）；5000με组与0με组相比Runx2m RNA表达显著增加（P〈0．01）。结论①生理强度的拉伸应变可显著增加MC3T3-E1细胞Runx2蛋白的表达，并且呈剂量依赖性，超生理强度5000με显著降低Runx2蛋白表达。②同样强度的拉伸应变刺激下，Runx2基因表达与蛋白表达并不一致。

英文摘要：

Objective To study the effect of substrate-stretching strain on the expression of Runx-2 by mouse MC3T3-E1 osteoblasts. Methods Six experimental groups were randomized divided to 0με, lO00με, 1500με, 2000με, 2500με, and 5000με groups. The ceils were loaded with substratc-stretching strain loading system. Runx-2 protein expression in cells with different strain groups was detected using western blotting. Runx-2 mRNA expression in cells subjected to 0με 2500με, and 5000με substrate- stretching strain was detected using real-time PCR. Results Western blotting results showed that the expressions of Runx-2 protein were significantly increased in 1500με, 2000με, and 2500μεgroups, 8nd decreased in 5000με group, comparing to that in 0tra group （P 〈 0.01 ）. Real-time PCR results showed that the expression of Runx-2 mRNA was significantly decreased in 2500με group, and increased in 50001x8 group, comparing to that in 0με group （P 〈 0.01 ）. Conclusion （ 1 ） Expression of Runx2 protein in MC3T3-E1 ceils could be up-regulated under physiological strain and the regulation was magnitude- dependent. The expression was down-regulated when the strain magnitude was beyond physiological load at5000με. （2） Expression of Runx2 mRNA was not consistent with the expression of the protein under the same strain magnitude.