关节-干骺端软骨细胞移植修复兔桡骨缺损

Repair of the gaps in the radii of rabbit with chondrocyte from articula-epiphysis-cartilage complex

目的研究组织工程软骨移植于成年兔桡骨缺损后的生长、分化与转归特点，以及引导性骨再生和骨缺损的修复机制。方法取自一日龄新生兔关节－干骺端复合物的软骨细胞在几丁质纤维网中增殖21d后装入硅胶管内，套接在成年兔桡骨干1cm的缺损处（实验组12只）；对照组10只在缺损处套接空硅胶管，2只仅填入裸几丁质纤维。术后4周两组各处死3只动物取材，其余在术后16周取材。结果实验组术后4周3只动物的工程软骨组织在骨缺损内形成软骨样组织，术后16周9只动物中有2只动物的缺损愈合。对照组术后4周已开始骨愈合，术后16周9只动物的骨缺损全部愈合。结论新生兔关节－干骺端复合物的软骨细胞在成年兔桡骨缺损区（套管内）未肥大钙化，未再现软骨内化骨过程。缺损内的工程软骨可能因占据空间、阻碍成骨成分进入而中断了骨缺损修复过程。引导性骨再生的机制可能是人工膜管加强了骨膜的天然引导作用而促进了骨愈合。

Objective To study the results and the mechanism of the guided hone regeneration and the healing of the bone after transplantation of the tissue-engineered cartilage into the radial defects in rabbits.Methods The seeding chondrocyte harvested from the articular-epiphyseal complex of a new born rabbit by enzyme was cultured in vitro with fibrous chitin mash. When most of the mash was covered with the new chondrocyte (21 days), the mash with chondrocyte (tissue-engineered cartilage) were filled into silicon tubes,which bridged the 1 cm gaps in the radius of the 12 adult rabbits (study group). While the gaps in the control group were connected with empty tubes. Three animals of each group were sacrificed in 4 weeks and the others were killed in the 16 weeks postoperatively. Results In the study group (4 weeks), 3 of the defects were filled with cartilage-like tissue. In the 16 weeks 2 of the 9 defects healed with bone, no cartilage-like tissue presented in the gaps. In the control group, 3 gaps began to heal in 4 weeks and all of the 9 defects healed with bone in 16 weeks. Conclusion The hypertrophic osteogenic process did not happen in the tissue-engineered cartilage in the radial defects(in the silicon tubes) and enchondrol ossification was not seen;the result probably indicated chondrocyte propagated from articular-epiphyseal complex could not grow into osteoblast and the cartilage in the defects may block the osteogenic factors entering the defect as well. The mechanism of guided bone regeneration might be the strengthening of the natural 'guiding process' of the periosteum following the implantation of the artificial membranous tube.