Laboratory of Preclinical and Surgical Studies, IRCCS-Istituto Ortopedico Rizzoli, Via Di Barbiano 1/10, 40136 Bologna, Italy.
Injury. 2020 Jul;51(7):1457-1467. doi: 10.1016/j.injury.2020.04.010. Epub 2020 May 12.
Large bone defects in long bone are not able to repair themselves and require grafts. Although autograft is the gold standard, it is associated with some disadvantages. Consequently, the application of tissue engineering (TE) techniques help with the use of allogenic biological and artificial scaffolds, cells and growth factors (GFs). Following 3Rs and in vitro testing strategies, animal models are required in preclinical in vivo studies to evaluate the therapeutic effects of the most promising TE techniques.
A systematic review was performed from 2000 to 2019 to evaluate bone regeneration sheep metatarsus defects.
Eleven in vivo studies on sheep metatarsus defect were retrieved. The mid-diaphysis of metatarsus was the region most employed to perform critical size defects. Natural, synthetic and hybrid scaffolds were implanted, combined with bone marrow mesenchymal stem cells (BMSCs), GFs such as osteogenic protein 1 (OP1) and platelet rich plasma (PRP). The maximum follow-up period was 4 and 6 months in which radiography, histology, histomorphometry, computed tomography (CT) and biomechanics were performed to evaluate the healing status.
the sheep metatarsus defect model seems to be a suitable environment with a good marriage of biological and biomechanical properties. Defects of 3 cm are treated with natural scaffolds (homologous graft or allografts), those of 2.5 cm with natural, synthetic or composite scaffolds, while little defects (0.5 × 0.5 cm) with composite scaffolds. No difference in results is found regardless of the defect size.
长骨的大骨缺损无法自行修复，需要进行移植。虽然自体移植物是金标准，但它也存在一些缺点。因此，组织工程（TE）技术的应用有助于使用同种异体生物和人工支架、细胞和生长因子（GFs）。在遵循 3R 和体外测试策略的情况下，需要在临床前体内研究中使用动物模型来评估最有前途的 TE 技术的治疗效果。
对 2000 年至 2019 年期间评估羊跖骨缺损骨再生的体内研究进行了系统性回顾。
共检索到 11 项关于绵羊跖骨缺损的体内研究。跖骨的中干骺端是最常用于进行临界尺寸缺陷的区域。天然、合成和杂交支架与骨髓间充质干细胞（BMSCs）、骨形成蛋白 1（OP1）和富含血小板的血浆（PRP）等生长因子一起被植入。在最长 4 至 6 个月的随访期间，通过 X 线摄影、组织学、组织形态计量学、计算机断层扫描（CT）和生物力学评估愈合状态。
羊跖骨缺损模型似乎是一种具有良好生物和生物力学特性的合适环境。3cm 的缺损用天然支架（同源移植物或同种异体移植物）治疗，2.5cm 的缺损用天然、合成或复合支架治疗，而小的缺损（0.5×0.5cm）用复合支架治疗。无论缺损大小如何，结果均无差异。
