Zhou Guangdong, Liu Wei, Cui Lei, Wang Xiaoyun, Liu Tianyi, Cao Yilin
Department of Plastic and Reconstructive Surgery, 9th People's Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, PR China.
Tissue Eng. 2006 Nov;12(11):3209-21. doi: 10.1089/ten.2006.12.3209.
In vivo niche is known to play important roles in terminal differentiation of implanted bone marrow stromal cells (BMSCs). This study explored the feasibility of repairing articular osteochondral defects using autologous BMSCs and biodegradable polymers. BMSCs from 18 hybrid pigs' marrows were either treated with dexamethasone (40 ng/mL) alone or chondrogenically induced with dexamethasone and transforming growth factor-beta1 (10 ng/mL). The cells were seeded respectively onto polylactic acid (PLA)- coated polyglycolic acid (PGA) scaffolds. Four osteochondral defects in each animal were created at non-weightbearing areas of knee joints (2/each side) and were respectively repaired by a chondrogenically induced BMSC-PGA/PLA construct in experimental group (Exp), by a dexamethasone-treated BMSC-PGA/PLA construct in control 1 group (Ctrl 1), by a PGA/PLA construct alone in control 2 group (Ctrl 2), or left unrepaired in control 3 group (Ctrl 3). To trace the implanted cells, green fluorescent protein (GFP)- labeled BMSCs were implanted in 2 animals. Gross view and histology showed that Exp and Ctrl 1 (with cell implantation) achieved better reparative results than Ctrl 2 and Ctrl 3 (without cell implantation) in terms of the reparative level and the restoration of the histological structure. In addition, 6-month results were better than 3-month results in all 4 groups. In Exp, 11 of 16 defects were completely repaired by hyaline cartilage and cancellous bone. In Ctrl 1, 11 of 16 defects were repaired by fibrocartilage and cancellous bone, although the repair with hyaline cartilage and cancellous bone was observed in 5 of 16 defects. In contrast, no obvious repair or only fibrotic tissue was observed in Ctrl 2 and Ctrl 3. The compressive moduli of repaired cartilage in Exp reached 80.27% of the normal amount at 6 months, with a high level of glycosaminoglycan (GAG) content (no statistical difference from normal). In Ctrl 1, the compressive moduli and GAG content were 62.69% and 78.03% of normal levels, respectively. More importantly, GFP-labeled cells were detected in the engineered cartilage and the repaired subchondral bone. These results strongly indicate that the implanted BMSCs can differentiate into either chondrocytes or osteoblasts and repair articular osteochondral defects by forming engineered cartilage and engineered bone.
已知体内微环境在植入的骨髓间充质干细胞（BMSC）的终末分化中起重要作用。本研究探讨了使用自体BMSC和可生物降解聚合物修复关节软骨下骨缺损的可行性。从18只杂种猪的骨髓中获取的BMSC，要么单独用地塞米松（40 ng/mL）处理，要么用地塞米松和转化生长因子-β1（10 ng/mL）进行软骨诱导。将细胞分别接种到聚乳酸（PLA）包被的聚乙醇酸（PGA）支架上。在每只动物的膝关节非负重区域制造4个软骨下骨缺损（每侧2个），实验组（Exp）用软骨诱导的BMSC-PGA/PLA构建体修复，对照组1（Ctrl 1）用地塞米松处理的BMSC-PGA/PLA构建体修复，对照组2（Ctrl 2）仅用PGA/PLA构建体修复，对照组3（Ctrl 3）不进行修复。为了追踪植入的细胞，将绿色荧光蛋白（GFP）标记的BMSC植入2只动物体内。大体观察和组织学检查表明，就修复水平和组织结构的恢复而言，Exp组和Ctrl 1组（有细胞植入）比Ctrl 2组和Ctrl 3组（无细胞植入）取得了更好的修复效果。此外，所有4组的6个月结果均优于3个月结果。在Exp组中，16个缺损中有11个被透明软骨和松质骨完全修复。在Ctrl 1组中，16个缺损中有11个被纤维软骨和松质骨修复，尽管16个缺损中有5个观察到透明软骨和松质骨修复。相比之下，Ctrl 2组和Ctrl 3组未观察到明显修复或仅有纤维化组织。Exp组修复软骨的压缩模量在6个月时达到正常水平的80.27%，糖胺聚糖（GAG）含量较高（与正常无统计学差异）。在Ctrl 1组中，压缩模量和GAG含量分别为正常水平的62.69%和78.03%。更重要的是，在工程化软骨和修复的软骨下骨中检测到了GFP标记的细胞。这些结果有力地表明，植入的BMSC可以分化为软骨细胞或成骨细胞，并通过形成工程化软骨和工程化骨来修复关节软骨下骨缺损。
