Bone tissue engineering induced composite scaffolds for repair of bone defects

Tang Jun-jie; Li Wen-jie; Li Gen; Wang Jiu-na; Zhao Ling; Qin Wen; Zhao Hong-bin

doi:10.3969/j.issn.2095-4344

Abstract：BACKGROUND:In the early experiments, icarin chitosan/colagen/polycaprolactone/hydroxyapatite (CS/Col/PCL/HA) composite scaffold has good physical and chemical properties. <br> OBJECTIVE: To study the effect of CS/Col/PCL/HA composite scaffolds to repair bone defects of rabbit tibia platform. <br> METHODS:The outer of Col/PCL/HA composite scaffolds were prepared by electrospinning, and the core containing chitosan microspheres/colagen was made by vacuum freeze-drying process. Then the core was implanted into the outer to construct the drug-loading composite scaffold by genipin crosslinking. The microspheres carrying icarin chitosan were immersed into PBS to observe the slow-release effect. The composite scaffold was used to culture rat bone marrow mesenchymal stem cels for 7 days to observe cel adhesion. Fifteen chinchila rabbits were taken to make the model of left tibia bone defect, and then randomly divided into three groups: CS/Col/PCL/HA composite scaffold group, Col/PCL/HA composite scaffold group, and blank control group with no materials. X-ray observation, gross observation, and histopathological observation were performed at 4, 12, 24 weeks after the surgery. <br> RESULTS AND CONCLUSION: The drug-loading composite scaffold had a porous structure that was conducive to cel adhesion and proliferation. Chitosan microspheres kept a 19% drug release within 72 hoursin vitro. Twenty-four weeks after surgery, CS/Col/PCL/HA composite scaffolds were completely covered by the newly formed bone tissue, and the scaffold surfaces were smooth and had hardness close to normal bone tissue; hematoxylin-eosin staining showed bone trabecula, bone cells and osteoblasts, but X-ray images showed the bone mineral density in the defect area was slightly lower than that of the normal bone tissue. Col/PCL/HA composite scaffolds were wrapped up by fibrous tissue, and hematoxylin-eosin staining showed bone trabecula, bone marrow cels and dense fibrous tissue. In the blank control group, the hardness of defect areas was significantly lower than that of the normal bone and hematoxylin-eosin staining showed a large number of bone marrow cels and bone trabeculae. The experimental results showed that CS/Col/PCL/HA composite scaffold could repair rabbit bone defects effectively.