靶向软骨的非病毒纳米基因载体体内外转染特性的研究

In vivo and in vitro cartilage transfection by a non-viral gene delivery system

目的采用一种靶向软骨的非病毒纳米基因传递系统，携带增强型绿色荧光蛋白（EGFP）在体内外对软骨细胞进行转染，探讨一种临床可用的促进软骨修复的方法。方法将高相对分子质量壳聚糖（HMWC）适度降解，成为低相对分子质量壳聚糖（LMWC），并与EGFP的质粒复合形成稳定的非病毒纳米基因传递系统。经过体外的转染实验后，这些纳米复合物被进一步注射到伴有全层软骨缺损的新西兰大白兔动物模型膝关节中，探讨其在体内传递治疗基因促进软骨修复的可能性。结果结果显示LMWC／DNA纳米复合物可以有效地转染体外单层培养的软骨细胞和软骨组织片。在体内应用时，LMWC／EGFP基因纳米复合物可以安全有效地转染软骨细胞，并表现出一定的靶向性。结论本研究显示了由LMWC／DNA纳米复合物介导的体内转染方法促进软骨修复的可行性，其有望成为一种简单、安全、有效、可控并且可早期使用的促进软骨修复的方法。

Objective To develop a clinically applicable approach to enhancing natural repair mechanisms by in vivo transfeetion using a non-viral gene delivery system targeting at chondroeytes. Methods High molecular weight chitosan （HMWC） was degraded to produce low molecular weight chitosan （LMWC） and combined with enhanced green fluorescent protein （EGFP） plasmid to form stable complexes of nano-size. After being tested in vitro, these nano-complexes were employed to animal models with full-thick cartilage defect to demonstrate the feasibility of delivering the report gene in vivo by intra-articular injections. Results The results showed that LMWC/DNA nano-complexes could deliver the gene into cultured chondrocytes and cartilage tissue efficiently both in vitro and in vivo. Conclusion LMWC/DNA nano-complexes can have a potential to be a safe and effective method of enhancing osteochondral defect repair in orthopaedics and sport medicine.