课题背景：经典的组织工程方法中最常使用的种子细胞是自体或同种异体来源的骨髓间充质干细胞，但其仍存在着不少局限性，如在体外培养中和软骨定向分化中对外源性生长引子的依赖性。本课题立足于此，通过前期实验，成功将hIGF-1基因导入兔骨髓间充质干细胞，对其进行了一定程度的基因改良，并将改良后的种子细胞与PLGA体外短暂复合培养后移植入缺损关节处以提高其修复效果。

同行评价：间充质干细胞与关节软骨缺损修复的研究是目前骨科领域的热点和难点之一，文章能紧贴此主题，追踪科技前沿进行实验，科研设计较合理，有一定临床实用价值。建议进一步增加实验动物数量及观察时间，以增强文章的说服力。

偏倚或不足：①本课题所使用的基因载体为携带了目的基因的质粒载体，相比较病毒类载体虽然有不整合宿主、携带DNA信息量大等优点，但存在有表达时间短、表达时限较短、稳定性较差等缺陷。②由于客观原因所限，未能获得移植术后12周以上更长时间的观察资料和数据，有待后续研究进一步完善。


摘要
目的：在前期成功构建携带有目的基因的质粒载体IRES2-EGFP-hIGF-1基础上，探索使用可吸收生物材料PLGA复合基因强化的同种异体骨髓间充质干细胞（mesenchymal stem cells,MSCs）移植修复兔关节软骨缺损的方法。
方法：实验于2005-09/2006-01在重庆医科大学儿科研究所完成。①选择3月龄新西兰大耳白兔18只，双下肢髁关节面上共制作4个直径3 mm、深3 mm的全层软骨缺损，自左到右为：空白对照组，PLGA移植组，PLGA-MSCs组（PLGA+空载体转染的MSCs移植），PLGA+hIGF-1-MSCs组（PLGA+hIGF-1转染的MSCs移植）。②分别于术后4，6，12周各处死6只，应用大体观察、组织学观察及组织学评分评估缺损软骨的修复情况、修复组织中hIGF-1和Ⅱ型胶原的表达情况、移植细胞GFP荧光强度等。
结果：16只兔进入结果分析，脱落2只。术后12周时，组织切片显示，PLGA+HIGF-1-MSCs组新生组织中可见大量类透明软骨细胞出现，Ⅱ型胶原丰富表达；荧光追踪显示PLGA-MSCs组和PLGA+hIGF-1-MSCs两组修复组织在4周时仍有可见的GFP表达；PLGA+hIGF-1-MSCs组各个时间点组织学评分均高于其他3组（P < 0.05）。
结论：PLGA与经过hIGF-1基因强化的MSCs复合移植提高了对兔关节软骨缺损的修复效果。
关键词；可降解生物材料；PLGA；关节软骨；骨髓间充质干细胞；基因强化；

丁幸坡，金先庆，王智勇，付艳丽.可降解生物材料复合基因强化干细胞移植修复兔关节软骨缺损[J].中国组织工程研究与临床康复，2008，12(10):1839-1842 [www.zglckf.com/zglckf/ejournal/upfiles/08-10/10k-1839(ps).pdf]

Repairing articular cartilage defects in rabbits by gene-modified stem cells transplantation of biodegradable materials

Abstract

AIM：Based on the IRES2-EGFP-hIGF-1 plasmid vector carrying target gene, this study was designed to research the method of repairing articular cartilage defects in rabbits by the transplantation of biodegradable PLGA scaffold compounded with allogeneic bone marrow mesenchymal stem cells (MSCs).
METHODS: The experiment was performed at the Pediatric Research Institute, Children's Hospital of Chongqing Medical University from September 2005 to January 2006.①Eighteen 3-months-old New Zealand rabbits were selected for making 4 models of articular cartilage defects in articular facets of both lower extremities, with 3 mm diameter and 3 mm depth. Four groups were divided as blank control group, PLGA scaffold transplantation group, PLGA scaffold compounded with MSCs transplantation group (modified by blank vector), and PLGA scaffold compounded with MSCs transplantation group (modified by hIGF-1 gene).②Every 6 animals were sacrificed at 4, 8, 12 weeks postoperatively. The observation of macroscopy and the score of histology were used to evaluate the repairs of knee joint articular cartilage defects in rabbits, the expressions of hIGF-1 and type II collagen, as well as GFP fluorescence intensity of transplanted cells.
RESULTS: Sixteen rabbits were involved in the result analysis, whereas 2 animals were lost. At 12 weeks postoperatively, histological observation showed that there were many cartilago-like cells in new tissues from defects field and abundant expression of type II collagen. At 4 weeks postoperatively, GFP expression was detected by fluorescence tracking in frozen section from PLGA-MSCs group and PLGA+hIGF-1-MSCs group. The histological score in the group transplanted by PLGA+hIGF-1-MSCs was higher than that in other three groups (P < 0.05).
CONCLUSION: After the gene is modified by hIGF-1, MSCs transplantation with PLGA can improve the repair effect on articular cartilage defects in rabbits.

Ding XP, Jin XQ, Wang ZY, Fu YL.Repairing articular cartilage defects in rabbits by gene-modified stem cells transplantation of biodegradable materials. Zhongguo Zuzhi Gongcheng Yanjiu yu Linchuang Kangfu 2008;12(10):1839-1842(China)
[www.zglckf.com/zglckf/ejournal/upfiles/08-10/10k-1839(ps).pdf]