剪切应力诱导成骨相关基因表达的研究

Study of gene expression in osteoblasts induced shear stress

目的探讨剪切应力对成骨细胞基因表达的影响,以期将剪切应力应用于组织工程。方法给予成骨细胞剪切应力的刺激以观察细胞内信息传递的改变,并进一步研究成骨相关基因的表达。使用MG63细胞株进行体外培养,给予12 dynes/cm^2的剪切应力,用Western blot观察信号转导分子的改变,包括促分裂原活化蛋白激酶[细胞外信号调节激酶、c-Jun氨基端激酶及P38]受到剪切应力后的情况,应用RT-PCR检测成骨相关基因COX-2,Egr-1,c-fos及骨桥蛋白的表达。结果剪切应力能促使MG63细胞内部的信号转导分子促分裂原活化蛋白激酶(细胞外信号调节激酶、c-Jun氨基端激酶及P38)磷酸化,进一步诱使成骨相关基因COX-2,Egr-1,c-fos及骨桥蛋白大量表达,此诱导表达可持续24h。结论剪切应力能启动成骨细胞内部的信息传递,进一步诱使成骨相关基因表达,此现象可以应用于组织工程．即应用剪切应力以体外培养的方式增加成骨细胞的生理活性。

Objective To elucidate the mechanotransduction pathways and gene expression in osteoblasts in response to fluid-induced shear stress in hope to be applied in tissue engineering. Methods Osteoblastic MG63 cells were exposed to shear stress of 12 dynes/cm^2 for the designated times and their activations of MAPK （i. e., ERK, JNK, and P38） were examined by western blotting. The expressions of bone formation-related genes, including COX-2, Egr-1, c-los, and OPN, were detected by RT-PCR. Results We found that shear stress induced phosphorylation of ERK, JNK, and P38 MAPK, and expressions of bone formation-related genes, including COX-2, Egr-1, c-los, and OPN. Conclusions Shear stress can turn on the signal transduction and enhance bone formation-related gene expression in osteoblasts. This phenomenon may imply that shear stress can be applied in tissue engineering.