Reves Benjamin T, Jennings Jessica A, Bumgardner Joel D, Haggard Warren O
Biomedical Engineering Department, University of Memphis, Memphis, TN 38115, USA.
Materials (Basel). 2011 Aug 2;4(8):1360-1374. doi: 10.3390/ma4081360.
The objective of this study was to evaluate the osteoinductivity of composite chitosan-nano-hydroxyapatite scaffolds in a rat muscle pouch model. Previous in vitro characterization demonstrated the ability of the scaffolds to promote bone regeneration and as a carrier for local delivery of BMP-2. Composite microspheres were prepared using a co-precipitation method, and scaffolds were fabricated using an acid wash to adhere beads together. To determine the in vivo osteoinductivity of the scaffolds, the following groups (n = 6) were implanted into muscle pouches created in the latissimus dorsi of Sprague Dawley rats: (A) lyophilized scaffolds without rhBMP-2, (B) lyophilized scaffolds with rhBMP-2, (C) non-lyophilized scaffolds with rhBMP-2, and (D) absorbable collagen sponge with rhBMP-2 (control). Groups B, C, and D were loaded with 4 mL of a 9.0 μg/mL solution of rhBMP-2 for 48 h. The rats were sacrificed after one month and samples were analyzed for amount of residual implant material, new bone, and osteoid. Although the experimental groups displayed minimal degradation after one month, all of the scaffolds contained small amounts of woven bone and considerable amounts of osteoid. Approximately thirty percent of the open space available for tissue ingrowth in the scaffolds contained new bone or osteoid in the process of mineralization. The ability of the composite scaffolds (with and without BMP-2) to promote ectopic bone growth in vivo was demonstrated.
本研究的目的是在大鼠肌肉袋模型中评估壳聚糖-纳米羟基磷灰石复合支架的骨诱导活性。先前的体外特性表征证明了该支架具有促进骨再生的能力，并可作为骨形态发生蛋白-2（BMP-2）局部递送的载体。采用共沉淀法制备复合微球，并通过酸洗将珠子粘附在一起制成支架。为了确定支架在体内的骨诱导活性，将以下几组（n = 6）植入在Sprague Dawley大鼠背阔肌中创建的肌肉袋中：（A）不含重组人骨形态发生蛋白-2（rhBMP-2）的冻干支架，（B）含rhBMP-2的冻干支架，（C）含rhBMP-2的非冻干支架，以及（D）含rhBMP-2的可吸收胶原海绵（对照）。B、C和D组用4 mL 9.0 μg/mL的rhBMP-2溶液加载48小时。一个月后处死大鼠，并分析样品中残留植入材料、新骨和类骨质的量。尽管实验组在一个月后降解极少，但所有支架均含有少量编织骨和大量类骨质。支架中可供组织长入的开放空间中约30%含有正在矿化的新骨或类骨质。证明了复合支架（含和不含BMP-2）在体内促进异位骨生长的能力。
