GFP基因转染对骨髓基质细胞体内向软骨细胞分化的示踪作用

目的 :实现绿色荧光蛋白 (greenfluorescentprotein ,GFP)报告基因在骨髓基质细胞 (BMSC)中的高效、稳定、持久表达 ,直接示踪BMSC在关节软骨缺损内的分布及分化。方法 :构建重组逆转录病毒表达载体RV GFP ,通过PT6 7包装细胞克隆、G4 18筛选及扩增 ,获得大量含GFP基因的假病毒液 ,并直接转染BMSC。将含有GFP基因转染标记的BMSC与生物可降解材料复合后 ,植入猪自体关节软骨缺损处 ,7个月后共聚焦显微镜检测修复组织中GFP标记的BMSC的分布及分化。结果 :经双酶切鉴定证实重组逆转录病毒表达载体RV GFP构建成功 ,转染PT6 7细胞后可在荧光激发波长下 ,发出明亮的绿色荧光 ,转染率达 2 0 %～ 5 0 % ,经G4 18筛选后可达 10 0 %。筛选、扩增后 ,PT6 7细胞的上清培养液可成功地转染BMSC ,筛选后能稳定、持久、高效表达GFP。将标记的BMSC植入关节软骨缺损 7个月后 ,修复组织仍能高效表达GFP ,激光共聚焦显微镜下显示 ,多数新生软骨陷窝内有GFP标记的细胞。结论 :构建的重组逆转录病毒GFP载体 ,能持久标记骨髓基质细胞 ,用于细胞动态变化的研究及细胞转归的示踪 ,该方法简便、灵敏、可靠、直观。标记的BMSC可在关节软骨缺损内分化为成熟的软骨细胞 ,并在软骨缺损的修复中发挥重要作用

In vivo tracing of bone marrow stromal cell differentiating into chondrocytes by green fluorescent protein gene transfection

AIM: To achieve highly efficient, stable and long-term expression of green fluorescent protein(GFP) reporter gene in bone marrow stromal cells(BMSCs) and to trace directly the distribution and differentiation of BMSCs in articular cartilage defects. METHODS: Recombinant RV-GFP expression vector was constructed and transfected into packaging cell PT67. After G418 screening and amplification, cell clones producing high level recombinant viruses were obtained and in-vitro expanded. The virus supernatant from infected PT67 cell culture was used to infect BMSCs directly. Autologous GFP-labeled BMSCs were seeded onto biodegradable polymer and implanted into porcine articular cartilage defects. 7 months later, the repaired tissue was evaluated by confocal microscope. RESULTS: The constructed recombinant expression vector RV-GFP was identified by restriction digestion. The transfection rates of PT67 cells reached 20%-50%, which reached 100% after G418 screening, bright green fluorescence could be seen under fluorescence microscope. BMSCs could be transfected successfully by the culture supernatant from infected PT67 cells and GFP was expressed efficiently in a long-term period. Confocal microscope revealed that GFP-labeled cells existed in many neocartilage lacunae after 7 months. CONCLUSIONS: The recombinant vector RV-GFP can provide a simple, sensitive and reliable tool to label BMSCs which can be used to study cytologic dynamic follow-up in-vivo. BMSCs can differentiate into chondrocytes and play an important role in repairing articular cartilage defects.