Aim: To assess the repair of bone defect with multilayer biomimetic nano-hydroxyapatite/chitosan composite scaffolds combining with or without autologous bone marrow. Methods: The experiments were completed in State Key Lab of Biomembrane and Membrane Biotechnology, Tsinghua University from September 2005 to May 2006. Ten New Zealand white rabbits were divided into 3 groups: 2 for the negative control group, 4 for scaffold-implanted group, and 4 for autologus bone marrow seeded scaffold-implanted group. Based on the preparation of nano-hydroxyapatite/chitosan composite scaffolds, a multilayer biomimetic scaffold was fabricated. After a 5 mm bone defect was made on each rabbit fibula, the multilayer biomimetic scaffold with or without autologous bone marrow was implanted into the defect site. The rabbits without any implant in defect sites were the control. The calcification in the defect site was evaluated with X-ray respectively at weeks 8 and 12 respectively after surgery. The rabbits were injected with tetracycline (25 mg/kg) before sacrificed. Then the calcification in the defect site was analyzed with the assessment of tetracycline fluorescence and Von Kossa staining after un-decalcified sliced. The bone regeneration in the defect site was assessed after decalcified sliced and hematoxylin-eosin (HE) staining. Results: Totally 10 rabbits were involved in the result analysis. 1 There was no obvious calcification at the defect site of the control rabbits, while in the implanted rabbits calcification was observed at weeks 8 after surgery. There was calcification in the implanted rabbits and more in the autologus bone marrow seeded scaffold-implanted group at weeks 12 after surgery and no obvious calcification in the control group yet. 2 The Von Kossa staining of un-decalcified slices showed that the bone defect sites of control rabbits were filled with fibrous tissues companied with a little muscle tissue incursion and no obvious calcified area was detected. However, in the center of bone defect of scaffold-implanted rabbits, black calcified area appeared in the middle of cells stained by neutral red. Many "calcified islands" appeared in the defect sites of the marrow seeded scaffold-implanted rabbits, which meant a higher level of bone-forming than other groups. 3 The results of tetracycline fluorescence assessment showed that in the area between of the two ends no fluorescence was detected in the negative control group, while in the scaffold-implanted rabbits a few calcified areas were detected. In the defect sites of bone marrow seeded scaffold-implanted groups many "calcified islands, appeared in a trend of connecting with each other, companied with more degradation. 4 The HE staining showed that in the implanted rabbits no mature fibrous tissue and many new-born blood vessels were observed. Bone regeneration was detected in the implanted rabbits and marrow-like tissue appeared in the autologus bone marrow seeded scaffold-implanted group. Conclusion: The multilayer biomimetic nano-hydroxyapatite/chitosan composite scaffolds facilitate the bone regeneration and the preload of autologous bone marrow enhances this process.
|Original language||English (US)|
|Number of pages||4|
|Journal||Journal of Clinical Rehabilitative Tissue Engineering Research|
|State||Published - Feb 4 2007|
ASJC Scopus subject areas
- Clinical Biochemistry
- Biomedical Engineering