Gelatin-chitosan-hydroxyapatite-minocycline biomimetic nanocomposite materials for repair of rabbit radius defects / 中国组织工程研究

ABSTRACT

BACKGROUND:Gelatin-chitosan-hydroxyapatite-minocycline biomimetic nanocomposite materials were developed in our previous studies. OBJECTIVE:To observe the capability of gelatin-chitosan-hydroxyapatite-minocycline biomimetic nanocomposite materials in the repair of rabbit radius defects. METHODS: Thirty healthy adult New Zealand rabbits were selected to make critical-size lacunar bone defects of the upper radius (15 mm×6 mm). Then, the rabbit models were randomized into experimental group (n=15), autogenous bone graft group (n=10) and blank group (n=5). Gelatin-chitosan-hydroxyapatite-minocycline biomimetic nanocomposite materials were implanted into radial bone defects in the experimental group. Bone defect in blank group was implanted without any materials; in the autogenous bone graft group, the contralateral radius with same length was taken and implanted into the defect. General observation, histological observation and X-ray observation were performed respectively at 2, 4, 8, 12 weeks postoperatively. RESULTS AND CONCLUSION:At 12 weeks after operation, the experimental group showed obvious new blood vessels at the defect region, complete bony union and disappearance of the composite implant, but lamelar bone structure appeared, smal blood vessels were visible, the edge of new bone was connected to the original bone edge, exhibiting a continuity of bone, the bone density was slightly lowered, and the defect region became unobvious. In the autogenous bone graft group, bony union and trabecular bone reconstruction were distinct, the lamelar bone became mature, the medulary cavity was recanalized, the fracture line disappeared completely, and the bone density was completely consistent with that of the original bone. In the blank group, there was no obvious bone formation, which led to bone nonunion, and there were a great amount of fiber tissues and inflammatory cel infiltrated. To sum up, the gelatin-chitosan-hydroxyapatite-minocycline biomimetic nanocomposite material can obviously promote the repair of critical-size bone defects, and the repairing effect is basicaly the same with that of autologous bone grafting.