釉基质蛋白控释微球的研制及其生物学性能的初步研究

目的　探讨载釉基质蛋白(EMPs)的右旋糖酐基凝胶微球(dex-MPs)的制备工艺及其理化与生物学性能。 方法　采用乳化化学交联技术制备载EMPs的dex-MPs (EMPs-dex-MPs),正交设计法优化制备工艺;观察EMPs-dex- MPs形态和粒径,测定其包封率与载药量;测定微球的溶胀、降解性能,动态透析法检测其体外释药特征及其影响因 素;通过EMPs-dex-MPs对体外培养的人牙周膜细胞(PDLCs)增殖和分化的影响,评价其生物学性能。结果　EMPs- dex-MPs形态规则,粒径25μm左右,分布较为均匀;EMPs载药量(32·8±1·2)%,包封率(78·9±1·0)%。体外释药 实验表明EMPs-dex-MPs中80%的EMPs在前20 d释放,在葡聚糖酶存在下40 d左右可以完全降解。与单纯EMPs 相比,EMPs-dex-MPs能持续促进PDLCs的增殖和分化达12 d左右。结论　dex-MPs作为活性生长因子载体,具有确 定的缓释作用,并可以通过制备工艺的改变控制其释药行为;EMPs-dex-MPs作为EMPs的一种新的给药方式,比传 统给药方式可以更加有效地促进牙周组织相关细胞的增殖与分化。

Preparation of Enamel Matrix Proteins Controlled Release Microspheres and Their Biological Effects on the Proliferation and Differentiation of Human Periodontal Ligament Cells in vitro

OBJECTIVE: To prepare enamel matrix proteins (EMPs) loaded dextran-based hydrogel microspheres (EMPs-dex-MPs), and to evaluate their EMPs controlled release property and their biological effects on the proliferation and differentiation of human periodontal ligament cells (PDLCs) in vitro. METHODS: Using dimethylbenzene as the oil phase, EMPs-dex-MPs were achieved by emulsion-chemical crosslinking technique. The process of the recombination preparation was optimized by orthogonal factorization method. The configuration and size of EMPs-dex-MPs were determined by scanning electron microscope. The EMPs loading content and encapsulation rate of EMPs-dex-MPs, and their biodegradation characteristic were studied by routine analysis methods. Dynamic dialysis method was used to determine the release characteristic of EMPs-dex-MPs in vitro and its influencing factors. The proliferation of cultured PDLCs was measured by MTF method and the differentiation of PDLCs was measured by their alkaline phosphatase (ALP) activities. RESULTS: The results showed that EMPs-dex-MPs were homogenous and stable with the average diameter 25 microm, and the EMPs loading content was (32.8 +/- 1.2)%, the encapsulation rate was (78.9 +/- 1.0)%. Under 9% physiological saline solution contained a very thimbleful quantity of dextranase EMPs-dex-MPs could be biodegraded completely during about 40 days. The in vitro experiments showed that about 80% of EMPs could be released out in 20 days. Using EMPs-dex-MPs could enhance the proliferation responses and ALP activities of PDLCs more than 12 days. CONCLUSION: As a new sustained release system of growth factors, the dex-MPs is stable, workable and biodegradable. EMPs-dex-MPs, whose drug release can be controlled by preparation technique, may be more effective in promoting periodontal tissue regeneration.