稳定表达人骨形成蛋白-2基因的成纤维细胞体内诱导成骨作用

目的 探讨稳定表达人骨形成蛋白—2(hBMP—2)基因的成纤维细胞是否具有体内诱导成骨能力。方法 构建置组真核表达载体pcDNA3—hBMP—2，在脂质体介导下，将其导入NIH3T3细胞，通过G418馈选获得阳性克随，并继续培养4周，用细胞原位杂交和免疫组织化学方法观察hBMP—2基因在NIH3T3细胞内的稳定表达，并观察了稳定表达hBMP—2的成纤维细胞碱性磷酸酶(ALP)活性的变化，将稳定表达hBMP—2的成纤维细胞植入裸鼠肌袋内观察其体内诱导成骨作用。结果 成功构建重组真核表达载体pcDNA3—hBMP—2，经细胞原位杂交和免疫组织化学证实，转染pcDNA3—hBMP—2后的NIH3T3细胞内有大量hBMP—2mRNA的转录及其蛋白的稳定表达，稳定表达hBMP—2的成纤维细胞ALP活性显著上升，植入裸鼠肌袋内4周有大量软骨形成。结论 稳定表达hBMP—2的成纤维细胞具有体内诱导成骨能力。

IN VIVO ENDOCHONDRAL BONE FORMATION BY IMPLANTING HUMAN BONE MORPHOGENETIC PROTEIN-2-PRODUCING FIBROBLASTS INTO NUDE MOUSE MUSCLE

Objective To determine whether fibroblasts can be used to promote endochondral bone formation in vivo by transfer of human bone morphogenetic protein-2(hBMP-2) into fibroblasts. Methods pcDNA3-hBMP-2 was constructed by use of gene clone and recombined technique.NIH3T3 fibroblasts were transfected with pcDNA3-hBMP-2. The positive cell clones were selected with G418. In NIH3T3 fibroblasts transferred with pcDNA3-hBMP-2, the expression of hBMP-2 was determined by in situ hybridization and immunohistochemical analysis; alkaline phosphatase activity was measured. hBMP-2-producing fibroblasts were implanted into nude mouse muscle to observe endochondral bone formation in vivo. Results pcDNA3-hBMP-2 was successfully constructed. In NIH3T3 fibroblasts transfected with pcDNA3-hBMP-2, the BMP-2 expression was stable; alkaline phophatase activity was much higher than that in non- transfected NIH3T3 cells. Endochondral bone formation in vivo was observed at the site of implantation 4 weeks later. Conclusion Fibroblasts transfected by hBMP-2 gene can be used to promote endochondral bone formation in vivo.