3D打印含镁聚己内酯支架修复大鼠颅骨缺损

3D printed Mg-incorporated polycaprolactone scaffolds for repairing rat skull defects

摘要

目的 评价3D打印含镁（Mg）聚己内酯（polycaprolactone，PCL）支架在大鼠颅骨缺损模型中的骨修复效果。方法 通过3D打印技术制备掺杂Mg微粒的PCL支架，以纯PCL支架为对照组，用扫描电镜（scanning electron microscopy，SEM）观察两种支架的表面形貌，用能谱分析仪（energy dispersive spectroscopy，EDS）分析表面元素成分，并通过接触角仪和电子万能试验机对其材料学性能进行表征。此外，将PCL-Mg支架浸入磷酸盐缓冲液中，连续28 d检测镁离子的释放行为。本研究已通过单位伦理委员会审查批准。建立SD大鼠颅骨临界尺寸缺损模型，根据植入支架材料不同，15只SD大鼠分为3组：PCL组、PCL-Mg组和对照组（未作处理），每组5只。术后4周和8周进行micro-CT扫描检测分析，并在8周后获取颅骨缺损区样本及大鼠主要脏器进行组织学染色。结果 通过3D打印技术制备掺杂Mg微粒的PCL支架孔径为（480 ± 25）μm，纤维直径为（300 ± 25）μm，孔隙率约为66%。PCL-Mg支架含Mg 1.0 At%，表明Mg微粒的成功掺杂。PCL-Mg支架的接触角为68.97° ± 1.39°，压缩模量为（57.37 ± 8.33）MPa，相较PCL支架显示出更好的润湿性和机械强度。在术后4 ~ 8周的观察期内，与对照组及PCL组相比，在PCL-Mg组大鼠颅骨缺损区观察到最佳的新生骨形成，其骨再生指标新生骨体积、骨体积分数、骨表面积、骨表面积组织体积比、骨小梁厚度、骨小梁数和骨矿物密度均显著优于对照组、PCL组。另外，H&E染色、Glodner染色和VG染色结果显示PCL-Mg组诱导较多的矿化新生骨形成，同时主要脏器H&E染色提示良好的生物安全性。结论 PCL-Mg支架能够促进骨缺损的修复，为颌面部骨缺损修复提供了新的支架材料选择，具有潜在的临床应用前景。

Abstract

Objective To evaluate the bone repair effect of 3D-printed magnesium (Mg)-loaded polycaprolactone (PCL) scaffolds in a rat skull defect model. Methods PCL scaffolds mixed with Mg microparticles were prepared by using 3D printing technology, as were pure PCL scaffolds. The surface morphologies of the two scaffolds were observed by scanning electron microscopy (SEM), and the surface elemental composition was analyzed via energy dispersive spectroscopy (EDS). The physical properties of the scaffolds were characterized through contact angle measurements and an electronic universal testing machine. This study has been reviewed and approved by the Ethics Committee. A critical size defect model was established in the skull of 15 Sprague-Dawley (SD) rats, which were divided into the PCL group, PCL-Mg group, and untreated group, with 5 rats in each group. Micro-CT scanning was performed to detect and analyze skull defect healing at 4 and 8 weeks after surgery, and samples from the skull defect area and major organs of the rats were obtained for histological staining at 8 weeks after surgery. Results The scaffolds had a pore size of (480 ± 25) μm, a fiber diameter of (300 ± 25) μm, and a porosity of approximately 66%. The PCL-Mg scaffolds contained 1.0 At% Mg, indicating successful incorporation of Mg microparticles. The contact angle of the PCL-Mg scaffolds was 68.97° ± 1.39°, indicating improved wettability compared to that of pure PCL scaffolds. Additionally, compared with that of pure PCL scaffolds, the compressive modulus of the PCL-Mg scaffolds was (57.37 ± 8.33) MPa, demonstrating enhanced strength. The PCL-Mg group exhibited the best bone formation behavior in the skull defect area compared with the control group and PCL group at 4 and 8 weeks after surgery. Moreover, quantitative parameters, such as bone volume (BV), bone volume/total volume (BV/TV), bone surface (BS), bone surface/total volume (BS/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N) and bone mineral density (BMD), of skull defects were better than those in the other groups, indicating the best bone regeneration effect. H&E, Goldner, and VG staining revealed more mineralized new bone formation in the PCL-Mg group than in the other groups, and H&E staining of the major organs revealed good biosafety of the material. Conclusion PCL-Mg scaffolds can promote the repair of bone defects and have clinical potential as a new scaffold material for the repair of maxillofacial bone defects.

关键词

骨缺损 / 颅骨缺损 / 骨再生 / 骨组织工程 / 支架 / 3D打印 / 聚己内酯 / 镁 / 新生骨体积 / 骨体积分数

Key words

bone defect / skull defect / bone regeneration / bone tissue engineering / scaffolds / 3D printing / polycaprolactone / magnesium / bone volume / bone volume/total volume

Author summay

李筱叶，医师，学士，Email：[e-mail]