人骨形态发生蛋白-2基因转染脂肪源性间充质干细胞的成骨研究

目的 探讨人骨形态发生蛋白-2（hBMP-2）基因修饰的人脂肪源性间充质干细胞（ADSCs）的成骨能力及基因转染对ADSCs成骨分化的生物学调控。方法 流式细胞技术鉴定从人脂肪组织中提取的细胞为间充质来源的干细胞。将ADSCs转染hBMP＋2基因，免疫沉淀＋Western blotting法和酶联免疫吸附试验（ELISA）检测hBMP-2表达，确定hBMP-2表达量及表达稳定性，碱性磷酸酶（ALP）染色、ALP定量测定、钙结节染色及RT—PCR分析hBMP-2基因转染对ADSCs向成骨细胞转化的调控，并将转基因细胞注入裸鼠股部肌内，通过X线及组织学检查观察体内成骨情况。结果 流式细胞术证实从脂肪中提取的细胞为间充质来源的干细胞。转基因后免疫沉淀＋Western blotting法和ELISA法显示转染hBMP-2的ADSCs具有较高且稳定的hBMP-2的表达，转染21d后表达量无明显降低。ALP染色、ALP定量测定、钙结节染色及RT—PCR发现转基因ADSCs向成骨细胞方向发生分化。裸鼠肌内注射转基因细胞后2周即显示有异位骨形成，4周明显增多，对照组无骨组织形成。结论 转染hBMP-2基因的ADSCs在持续稳定高表达目的蛋白的同时，自身向成骨细胞发生分化，并在裸鼠体内形成异位骨。因此，ADSCs有望作为新的基因工程种子细胞。

Osteogenic potential of hBMP-2 gene transduced human adipose-derived stem cells

Objective To investigate the ostengenie potential of adipose-derived stem cells(AD- SCs)when exposed to adenovirns containing hBMP-2 cDNA(Adv-hBMP-2)and offer a choice of cell source for gene therapy and tissue engineering.Methods Human adipose tissues were obtained from patients who received orthopaedic surgery or liposuction.ADSCs were obtained by digesting the adipose tissues.Firstly,flowcytometric analysis was performed for the confirmation of mesenchymal stem cell ori- gin and the surface markers including CD34,CD44,CD68,CD71,CD90,and CD105.The ADSCs were transfected by Adv-hBMP-2 and the effects were tested in vitro,lmmunoprecipitation and Western blotting and ELISA were performed for confirming BMP gone transduction and its stable expression.The transform of ADSCs was assessed by extracellular ALP staining,intracellular ALP spectrophotometry,von Kossa staining and RT-PCR.In the in vivo experiment ADSC-Adv-hBMP-2 cells were injected into the hind limb of nude mice and analyzed radiographically and histologically.Results ADSCs were successfully isolated from human adipose tissues.The isolated ADSCs expressed CD44,CD71,CD90 and CD105 and CD34 and CD68 were absent.The result confirmed the mesenchymal stem cell origin of the cells.West- ern blotting and ELISA confirmed successful and persistent hBMP-2 production by ADSC-Adv-hBMP-2 cells.Extracellular ALP staining,intracellular ALP spectrophotometry,yon Kossa staining and RT-PCR revealed that ADSCs treated with Adv-hBMP-2 had a tendency of transfering into osteoblast.X-ray and H&E sections from hind limb of nude mice injected with ADSC-Adv-hBMP-2 cells confirmed bone forma- tion at 2 weeks.Conclusions Liposuction aspirates contain abundant ADSCs that can be transduced with hBMP-2 gene,and the tranduced ADSCs differentiate into the osteoblast.ADSCs may be an ideal source of mesenchyme-lineage stem cells for gone therapy and tissue engineering.