壳聚糖作为缓释重组人骨形态发生蛋白-2载体的实验研究

In Vitro Experimental Study on Chitosan as Carrier for Sustained Release of Recombinant Human Bone Morphogenetic Protein-2

目的:将壳聚糖作为重组人骨形态发生蛋白2(rhBMP2)的载体,通过体外释放实验观测rhBMP2在壳聚糖中释放的动力学过程,探讨壳聚糖对rhBMP2的缓释作用。方法:采用乳液冷冻干燥法制作rhBMP2/壳聚糖支架,单纯壳聚糖支架为对照组。对材料进行扫描电镜观察;将支架材料在磷酸盐缓冲液(PBS)中持续浸泡,通过高效液相色谱分析仪检测不同时间点浸出液中rhBMP2的含量,进行累积释放量的动态观察,绘制rhBMP2释放曲线。结果:支架材料的形态学观察呈疏松多孔海绵状;rhBMP2从支架材料中释放的动力学过程第1天表现为“爆发性”释放(33.2%);第27天rhBMP2出现快速释放;第814天释放速度减慢;第1530天出现缓慢而持久的释放,至1个月释放量达81.3%。结论:多孔壳聚糖支架对rhBMP2有缓慢而持久的体外释放作用,可作为rhBMP2的缓释载体,为rhBMP2持续发挥骨诱导作用提供初步的实验基础。

Objective： To assess the feasibility of chitosan scaffold as the carrier for controlled release of recombinant human bone morphogenetic protein-2（rhBMP-2） and evaluate the release kinetics of rhBMP-2 through in vitro release test. Methods： The chitosan scaffolds with rhBMP-2 sustained release system were made by emulsion freeze-dried method, and were compared with the empty chitosan scaffolds as control group. The samples were observed with scanning electron microscope. The samples were immerged into phosphate buffer solution（PBS）. The released rhBMP-2 content from the samples was dynamically observed using high performance liquid chromatography at various set times. The curve of cumulative rhBMP-2 release kinetics was designed. Results： The surface and section of the scaffold was loose, multipore and sponginess. An initial burst release （33.2%） of the incorporated rhBMP-2 was observed during the first day; rhBMP-2 had been released rapidly during the 2nd to 7th day; released slowly during the 8th to 14th day;followed by a sustained release for the 15th to 30th day, which reached 81.3% at the 30th day. Conclusion： It can be concluded that the loose chitosan showed its characteristics as a sustained delivery system for rhBMP-2 and may be used as a sustained release carrier for rhBMP-2. It provided initial elements for rhBMP-2 continually inducing bone formation in bone tissue engineering.