Abstract：Objective To prepare the chitosan hydrogel as release carrier of recombinant human bone morphogenetic protein 2 (rhBMP-2), and loaded the prepared recombinant human bone morphogenetic protein 2 chitosan hydrogel in novel HA/ZrO2 gradient biocomposite artificial vertebrae and study bone reparation effect of it in a beagle dog′ vertebral defect model.Methods To prepare rhBMP-2 chitosan hydrogel by ion-crosslinked method. Scanning electron microscopy was used to observe lyophilized chitosan microscopic surface morphology, test its swelling coefficient and detect drug loading mass, encapsulation efficiency and sustained release characteristics of the chitosan hydrogel loaded with rhBMP-2. Loaded the rhBMP-2 chitosan hydrogel onto novel HA/ZrO2 gradient biocomposite artificial vertebrae. Then 12 beagle dogs were randomly divided into three groups (A, B, and C) by number table, each group included four dogs. Afterwards, a 23 mm radius and 9 mm high semi-cylindrical bone defect model was caused by surgery in each dog. While the bone defect location was implanted artificial vertebral body composite rhBMP-2 chitosan gel in group A, implanted artificial vertebral body composite blank dried chitosan in group B, and implanted autologous bone in group C. After operations, general observation and X-ray observation were carried out at week 6,12, and 24. At week 24, all beagle dogs were sacrificed and taken vertebral body specimens, then detect new bone volume in the artificial vertebral body by Micro-CT and detect ultimate compressive strength by biomechanical testing.Results SEM scanning showed the lyophilized chitosan was a three-dimensional network structure with uniform distribution of chitosan microspheres internal. When loaded with rhBMP-2, chitosan hydrogel encapsulation efficiency was 91.88%±1.53%, the loaded mass of drug was (39.84±2.34) ng/mg; the release rate was 28.32%±3.01% at day 1, 48.92%±6.27% at day 3, and 74.40%±6.29% at day 12. The average recovery ratio of group C was faster than group A and group B at 6 weeks postoperatively(all P values＜0.05), and there was no statistically signifficant difference between group A and group B(P＞0.05). 12 and 24 weeks postoperatively, there was satistically significant difference between group B and group C(all P values＜0.05), and there was no statistically signifficant difference between group A and group C(P＞0.05).X-ray imaging observation showed: in group A, with the passage of time after vertebral replacement surgery, callus formation gradually increased around the material, the gap between artificial vertebrae and autogenous bone was gradually filled with new bone. Since the artificial vertebrae and autologous bone had almost closely banded at week 24 with no obvious boundary; in group C, there were apparently self-absorption and bone osteolysis on non-load bearing areas at week 12 and 24, and appeared rapidly autologous bone remodeling; in group B, however, the repair to bone defect was slower than that of group A and group C. The specimens were taken at week 12. And in vitro Micro CT observation showed that three dimensional CT reconstruction could be seen a large number of new bone formation inside the artificial vertebral, and bone volume detection result at week 24 were (145.38±18.52) mm3 in group A and (86.30±15.60) mm3 in group B, there was significant difference between the two groups (t=4.879, P＜0.01). Ultimate compressive test showed the maximum compressive strengths of vertebras were (14.03±1.67) MPa in group A; (8.62±1.24) MPa in group B, and (13.78±1.43) MPa in group C. The group A and group C were significantly higher than that of group B in statistics analysis (all P values<0.01). There was no statistically significant difference between group A and group B(P＞0.05).Conclusions The novel HA/ZrO2 gradient biocomposite artificial vertebrae loaded with rhBMP-2 can excellently repair vertebral defect, it may be an ideal bone substituted material for clinical application.
全仁夫,谢尚举,李强,曹国平,庄伟,张亮,邵荣学,严世贵,杨迪生. 复合重组人骨形态发生蛋白2壳聚糖缓释水凝胶的新型HA/ZrO2多孔泡沫陶瓷人工椎体修复犬脊椎骨缺损[J]. 中华解剖与临床杂志, 2016, 21(1): 57-63.
Quan Renfu, Xie Shangju, Li Qiang, Cao Guoping, Zhuang Wei, Zhang Liang, Shao Rongxue, Yan Shigui, Yang Disheng. Research on novel HA/ZrO2 gradient biocomposite artificial vertebrae loaded by recombinant human bone morphogenetic protein. Chinese Journal of Anatomy and Clinics, 2016, 21(1): 57-63.
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2016, Vol. 21 
