Department of Orthopedics, the Second Hospital of Shandong University, Medical School, Shandong University, Jinan, Shandong 250033, China.
Chin Med J (Engl). 2012 Mar;125(5):906-11.
We previously showed that nano-hydroxyapatite/carboxymethyl chitosan (n-Ha/CMCS) displayed excellent mechanical properties, good degradation rates and exceptional biocompatibility, with negligible toxicity. The aim of this study was to determine the effect of the same composite with vascular endothelial growth factor (VEGF)- transfected bone marrow stromal cells (BMSCs) in a rabbit radial defect model.
The nano-hydroxyapatite was produced through co-precipitation. The n-HA/CMCS scaffold was produced by particle filtration and lyophilization followed by genipin crosslinking. Total RNA from rabbit bone was reverse-transcribed to synthesize VEGF165-pcDNA3.1 that was transfected into the BMSCs. The composite was implanted into a rabbit radial defect model, and the osteogenic activity examined by gross morphology, X-ray examination and hematoxylin and eosin (HE) staining.
The microstructure and mechanical property of the n-HA/CMCS scaffold resembled natural cancellous bone. Compared with glutaric dialdehyde crosslinked scaffolds, the genipin crosslinked scaffold was less toxic, and displayed a higher capacity to promote cell adhesion and proliferation. Spontaneous fluorescence of the composite permitted visualization of the composite-bone interface and the adhesion behavior of cells on the scaffold under laser scanning confocal microscopy. The scaffold with VEGF-transfected BMSCs bridged the bony defect and promoted healing, with most of the implanted material being replaced by natural bone over time with little residual implant. Using X-ray, we noted obvious callus formation and recanalization of the bone marrow cavity. Furthermore, HE stained sections showed new cortical bone formation.
The n-HA/CMCS scaffold composite with VEGF-trasnfected BMSCs is biocompatible, nontoxic, promotes the infiltration and formation of the microcirculation, and stimulates bone defect repair. Furthermore, the degradation rate of the composite matched that of growing bone. Overall, this composite material is potentially useful for bone defect repair.
我们之前的研究表明，纳米羟基磷灰石/羧甲基壳聚糖（n-Ha/CMCS）具有优异的力学性能、良好的降解率和卓越的生物相容性，几乎没有毒性。本研究旨在确定转染血管内皮生长因子（VEGF）的同种复合骨髓基质细胞（BMSCs）在兔桡骨缺损模型中的作用。
纳米羟基磷灰石通过共沉淀法制备。n-HA/CMCS 支架通过颗粒过滤和冻干后用京尼平交联制备。从兔骨中提取总 RNA，反转录合成 VEGF165-pcDNA3.1，转染 BMSCs。将复合物植入兔桡骨缺损模型，通过大体形态、X 射线检查和苏木精和伊红（HE）染色检查成骨活性。
n-HA/CMCS 支架的微观结构和力学性能与天然松质骨相似。与戊二醛交联支架相比，京尼平交联支架毒性较低，促进细胞黏附增殖的能力较高。复合物的自发荧光允许在激光扫描共聚焦显微镜下观察复合骨界面和细胞在支架上的黏附行为。转染 VEGF 的 BMSCs 的支架桥接骨缺损并促进愈合，随着时间的推移，大部分植入物被天然骨取代，残留的植入物很少。X 射线检查发现明显的骨痂形成和骨髓腔再通。此外，HE 染色切片显示新的皮质骨形成。
转染 VEGF 的 BMSCs 的 n-HA/CMCS 支架复合材料具有生物相容性、无毒、促进微血管渗透和形成，并刺激骨缺损修复。此外，复合材料的降解率与生长骨相匹配。总的来说，这种复合材料有望用于骨缺损修复。
