课题背景：课题在于将组织工程与骨折内固定相结合，建立合理的动物实验模型，研究各种骨诱导因子、骨髓基质干细胞等对促进骨愈合和防治骨坏死的单一或协同作用，探讨组织工程向临床应用转化的新方法，开辟股骨颈骨折及其并发症系列治疗的新途径。本部分实验首先制备重组人骨形态发生蛋白2/聚乳酸一聚乙二醇共聚物载药缓释微球，对影响微球成球性的主要因素进行探讨，以制备出适合粒径的微球，并对于制备微球的理化特性进行研究。

偏倚或不足：重组人骨形态发生蛋白2/聚乳酸一聚乙二醇共聚物微球具有良好的缓释效果和生物活性，是一种较为理想的生长因子载体材料。但将其植入机体后可能出现异物反应和无菌性炎症反应，对骨形态发生蛋白的局部骨诱导作用不利，同时难以在原位进行固化。因此，在解决原位固化基础上，同时减少或中和局部酸性物质是应用中值得注意的问题。

同行评价：文章针对重组人骨形态发生蛋白2易被机体的循环系统吸收、清除的问题，制备了重组人骨形态发生蛋白2/聚乳酸一聚乙二醇共聚物缓释微球并探讨微球的载药、释药特性，以期延长蛋白的药效。这项研究将有利于提高重组人骨形态发生蛋白2的临床应用效能。

摘要
目的: 针对重组人骨形态发生蛋白2(recombinant human bone morphogenetic protein-2,rhBMP-2)在体内半衰期短、易被稀释代谢的问题，探讨利用聚乳酸-羟基乙酸共聚物(PLGA)制备载rhBMP-2微球的可行性和制备工艺，并观察其载药、释药特性。
方法：①采用W/O/W型复乳化-溶剂挥发技术制备rhBMP-2/PLGA缓释微球，并对微球的粒径和形态、包封率和载药量，体外释放性质进行测定。②异位成骨实验：昆明小鼠12只，在右侧大腿股内侧肌袋内植入含rhBMP-2的50 mg PLGA微球，4周后取材，观察成骨情况以初步检测微球中的蛋白质活性。
结果：①rhBMP-2/PLGA缓释微球形态良好，粒径主要集中在50~60 μm，包封率为（37.52±4.31）%，载药率为（5.12±1.32）%。②微球的释放存在突释，7 d内释放的药物量超过40%，大约90%的药物量于42 d内释放完全。③载药微球植入鼠股部肌袋4周，材料周围有明显的骨形成。
结论:制备的rhBMP-2/PLGA微球可以缓慢释放有活性的rhBMP-2，具有临床应用的可行性。
关键词: 载药微球；rhBMP-2；聚乳酸聚乙醇酸；生物材料

唐佩福，姚琦，孙华燕，黄鹏，崔赓,王继芳.重组人骨形态发生蛋白2缓释微球的制备与评价[J].中国组织工程研究与临床康复，2008，12(6):1001-1004 [www.zglckf.com/zglckf/ejournal/upfiles/08-6/6k-1001(ps).pdf]

Preparation and evaluation of recombinant human bone morphogenetic protein-2 loaded microsphere

Abstract

AIM：Recombinant human bone morphogenetic protein-2 (rhBMP-2) is prone to dilute and conduct metabolism, with a short half-life period in vivo. This study investigated the feasibility and the preparation of rhBMP-2 carrying poly (lactic-co-glycolide) (PLGA), and observed drug-loading and drug-releasing function.
METHODS: ①The rhBMP-2/PLGA microspheres were prepared using W/O/W solvent evaporation method. The particle size and morphology of the microspheres, the drug loading, the efficiency of encapsulation and in vitro release behaviors were detected.②PLGA microspheres containing 50 mg rhBMP-2 were implanted into medial vastus muscle pouches of right lateral thigh in 12 Kunming mice, and the ectopic bone formation and the activity of rhBMP-2 released from the microspheres were evaluated 4 weeks later by the heterotopia bone formation experiment.
RESULTS: ①The rhBMP-2/PLGA microspheres showed good morphology with the particles diameter at 50-60 μm, the envelopment ratio (37.52±4.31)%, and the ratio of drug loading (5.12±1.32)%.②Initial burst release of the microspheres occurred, the drug release exceeded 40% within 7 days, and approximately 90% of the drugs was released within 42 days.③Four weeks after the rhBMP-2/PLGA implanted into muscle pouches of mice, obvious bone formation was detectable histologically.
CONCLUSION: The rhBMP-2/PLGA microspheres can release slowly active rhBMP-2, showing a potential clinical application.

Tang PF, Yao Q, Sun HY, Huang P, Cui G, Wang JF.Preparation and evaluation of recombinant human bone morphogenetic protein-2 loaded microsphere.Zhongguo Zuzhi Gongcheng Yanjiu yu Linchuang Kangfu 2008;12(6):1001-1004(China)
[www.zglckf.com/zglckf/ejournal/upfiles/08-6/6k-1001(ps).pdf]