Preparation and application of layered osteochondral composite scaffold in the repair of articular cartilage defects / 中国组织工程研究

ABSTRACT

BACKGROUND:Ideal osteochondral tissue-engineered scaffolds should be able to mimic the normal structure ofhuman articular cartilage. OBJECTIVE:To prepare a layered osteochondral composite scaffold based on the anatomical and physiological functions of osteochondral articular cartilage and to observe its repair effect on osteochondral defects in rabbits. METHODS:The poly (lactide-glycolide acid)/β-tricalcium phosphate organic solution was sprayed on the surface of cartilage scaffold using rapid prototyping technology. The layered osteochondral composite scaffold was formed by the“dissolving-adhesion”process. Sixty rabbits were enrol ed, modeled into left knee articular cartilage defects, and then randomly divided into three groups. The layered osteochondral composite scaffold and cartilage scaffold were implanted into experimental and control groups, respectively. Those without any treatment served as controls. Gross and histological observations of the defect region were performed at 12 and 24 weeks after implantation. RESULTS AND CONCLUSION:Gross observation:At 12 weeks after implantation, the defects in the control group were obvious and not repaired at al;the 24-week defect area was decreased, covered by newly formed tissues, but with rough surface. In the experimental group, the defect surface was flat after 12 weeks of implantation, the texture was soft, and the boundary with the surrounding tissues was unclear;at 24 weeks, the defect was covered with transparent cartilaginous tissues and the surface was smooth. Histological observation:At 12 weeks after implantation, the irregular cal us appeared in the control group, but the trabeculae were not formed;in the experimental group, the thickness of the new cartilage was similar with that of the normal cartilage and there was irregular trabecular bone under the cartilage. After 24 weeks of implantation, there were new tissues in the control group, but the thickness was irregular and uneven and the trabecular structure was irregular;while the cartilage surface was smooth and repaired wel in the experimental group. In contrast, repair effect in the control group was poor as assessed by gross and histological observations. These results show that the layered composite scaffold holds a similar structure with human articular cartilage and can promote the repair of articular cartilage defects.