Wang Wan-ming, Hu Yun-yu
Department of Orthopedics, Fuzhou General Hospital, Fuzhou, Fujian, P. R. China 350025.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2004 Jan;18(1):58-62.
To investigate the feasibility of cartilaginous implants containing bone marrow stromal cells (MSCs) derived from chondrocytes in biological resurfacing procedures for repairing articular cartilage defect.
MSCs derived from chondrocytes were obtained with high initial cell density subculture. An implant was constructed by dispersing the chondrocytes in a acid soluble type I collagen gel(5 x 10(6) cells/ml, final cell concentration). A full-thickness defect 3 mm x 5 mm was created in the trochlear groove of femur in 36 rabbits. A piece of cotton soaked in 0.5% trypsin was laid into the defect for 5 minutes, then the defect was filled with MSC/collagen gel implant on one side (n = 36), filled with a plain collagen gel on the other side (n = 18), and left empty as controls on the other side (n = 18). The animals were sacrificed at 4, 8, 12, 24, 32, and 48 weeks. The repaired tissue was examined and evaluated with Pineda grading scale.
In MSCs group, the implanted cells resembled well differentiated chondrocytes and were surrounded by metachromatic matrix and the reparative tissue resembled hyaline cartilage after 4 weeks; bone was formed at the base of the defects, the thickness of new cartilage was larger than tht of normal one after 8 weeks; the thickness was reduced proximally, approximating to that of normal cartilage, and chondrocyte columns was formed and subchondral bone and tidemark reappeared after 12 weeks; the thickness of the new tissue was about 55% of the normal tissue, with smooth surface and there were hypertrophic chondrocytes near the tidemark after 24 weeks; no hypertrophic chondrocytes were observed, indicating cessation of endochondral ossification after 32 weeks; the tissue architecture was the same as that at 32 weeks, hyaline-like cartilage persisting, with subchondral bone and tidemark in continuity after 48 weeks. The four layer cell orientation was not as clear as that of normal cartilage. The defects were partially filled with fibrous tissue in controls. At 32 weeks, erosive cartilage, naked subchondral bone and proliferative synovial membrane indicated the presence of osteoarthrosis. There were no statistical difference according to Pineda tissue scales in the specimens from the MSCs group between 24, 32, and 48 weeks, but there was significant difference between 4 weeks and 24, 32 and 48 weeks (P < 0.05). The joint function recovered after 2 weeks in MSCs group, while it deteriorated progressively in controls.
MSCs derived from chondrocytes improve repair of large full-thickness defect in articular cartilage. The reparative hyaline-like cartilage is stable differentiation after 24 weeks, maintains good joint function after 48 weeks.
探讨含软骨细胞来源的骨髓基质细胞（MSCs）的软骨植入物在关节软骨缺损生物修复手术中的可行性。
通过高初始细胞密度传代培养获得软骨细胞来源的MSCs。将软骨细胞分散于酸溶性I型胶原凝胶（5×10⁶细胞/ml，最终细胞浓度）中构建植入物。在36只兔的股骨滑车沟制造一个3mm×5mm的全层缺损。将一块浸有0.5%胰蛋白酶的棉花放入缺损处5分钟，然后一侧用MSC/胶原凝胶植入物填充缺损（n = 36），另一侧用普通胶原凝胶填充（n = 18），另一侧留作空白对照（n = 18）。在4、8、12、24、32和48周处死动物。用Pineda分级量表对修复组织进行检查和评估。
在MSCs组，植入细胞类似于分化良好的软骨细胞，4周后被异染性基质包围，修复组织类似于透明软骨；缺损底部形成骨，8周后新软骨厚度大于正常软骨；近端厚度减小，接近正常软骨，12周后形成软骨细胞柱，软骨下骨和潮标重新出现；24周后新组织厚度约为正常组织的55%，表面光滑，潮标附近有肥大软骨细胞；32周后未观察到肥大软骨细胞，表明软骨内成骨停止；48周时组织结构与32周时相同，透明样软骨持续存在，软骨下骨和潮标连续。四层细胞取向不如正常软骨清晰。对照组缺损部分被纤维组织填充。32周时，侵蚀性软骨、裸露的软骨下骨和增生的滑膜表明存在骨关节炎。MSCs组24、32和48周标本根据Pineda组织量表无统计学差异，但4周与24、32和48周有显著差异（P < 0.05）。MSCs组2周后关节功能恢复，而对照组则逐渐恶化。
软骨细胞来源的MSCs可改善关节软骨大的全层缺损的修复。修复的透明样软骨在24周后稳定分化，48周后维持良好的关节功能。
