Xia Yuanjun, Yu Xiang, Zhang Ying, Yin Qingshui, Xia Hong, Zheng Xiaohui, Xie Huibin, Huang Xianhua
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2016 Mar;30(3):286-91.
OBJECTIVE To evaluate the ectopic osteogenesis of recombinant human bone morphogenetic protein 2 (rhBMP-2) loaded chitosan (CS)/dextran sulfate (DS) by micro-CT.
rhBMP-2/CS/DS microspheres were prepared by the ionic crosslinking and its shape was observed under the scanning electron microscope. The release of rhBMP-2 was determined from resultant microspheres by ELISA assay. Forty-eight Sprague Dawley male rats were randomly divided into 4 groups (n = 12), quadriceps muscle bag model was made, gelatin sponge (group A), CS/DS microspheres (group B), rhBMP-2 (group C), and CS/DS/rhBMP-2 microspheres (group D) were implanted into the bags respectively. The tissue samples with heterotopic ossification were harvested for micro-CT scanning at 4, 8, 12, and 16 weeks. The tissue mineral density (TMD), bone volume fraction (BVF), trabecular thickness (Tb.Th), trabecular number (Tb.N), bone mineral density (BMD), and tissue mineral content (TMC) were measured.
The prepared rhBMP-2/CS/DS microspheres with smooth surfaces were spherical and evenly disperses without obvious agglomeration. At 2 hours, microsphere started a sudden release period in vitro; the release reached a peak at 2 days; and the release cycle lasted about 20 days. The rats survived to the end of the experiment. At each time point after operation, no radiation developed and no osteogenesis was observed by three dimensional reconstruction in groups A and B. However, radioactive strength and reconstructed bone tissue gradually increased in groups C and D, and group D had more radioautography and more bone tissues than group C. At each time point, TMD, BVF, Tb.Th, Tb.N, BMD, and TMC of groups A and B were zero. Ectopic bone formed with time, the other parameters showed an increasing trend except Tb.N in groups C and D, showing significant difference when compared with groups A and B at each time point (P < 0.05). There was no significant difference between groups C and D at 4 weeks (P > 0.05); the parameters of group D were significantly higher than those of group C at 8-16 weeks (P < 0.05).
rhBMP-2/CS/DS microspheres have stronger ability of ectopic bone formation than single rhBMP-2.
目的 通过显微CT评估负载重组人骨形态发生蛋白2（rhBMP-2）的壳聚糖（CS）/硫酸葡聚糖（DS）的异位骨生成情况。
采用离子交联法制备rhBMP-2/CS/DS微球，并在扫描电子显微镜下观察其形态。通过ELISA法测定rhBMP-2从所得微球中的释放情况。将48只雄性Sprague Dawley大鼠随机分为4组（每组n = 12），制作股四头肌袋模型，分别将明胶海绵（A组）、CS/DS微球（B组）、rhBMP-2（C组）和CS/DS/rhBMP-2微球（D组）植入袋中。在4、8、12和16周时收集异位骨化的组织样本进行显微CT扫描。测量组织矿物质密度（TMD）、骨体积分数（BVF）、小梁厚度（Tb.Th）、小梁数量（Tb.N）、骨矿物质密度（BMD）和组织矿物质含量（TMC）。
制备的rhBMP-2/CS/DS微球表面光滑，呈球形，均匀分散，无明显团聚。在2小时时，微球在体外开始突发释放期；在2天时释放达到峰值；释放周期持续约20天。大鼠存活至实验结束。术后各时间点，A组和B组未发生放射性显影，三维重建未观察到骨生成。然而，C组和D组的放射性强度和重建骨组织逐渐增加，且D组的放射自显影片和骨组织比C组更多。各时间点，A组和B组的TMD、BVF、Tb.Th、Tb.N、BMD和TMC均为零。异位骨随时间形成，C组和D组除Tb.N外的其他参数呈上升趋势，各时间点与A组和B组相比差异有统计学意义（P < 0.05）。4周时C组和D组之间差异无统计学意义（P > 0.05）；8 - 16周时D组的参数显著高于C组（P < 0.05）。
rhBMP-2/CS/DS微球的异位骨形成能力比单一rhBMP-2更强。
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