Attia Tarik, Grynpas Marc, Willett Thomas
Musculoskeletal Research Laboratory, Mount Sinai Hospital - Lunenfeld Tanenbaum Research Institute, Toronto, ON, Canada.
Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada.
Cell Tissue Bank. 2019 Jun;20(2):287-295. doi: 10.1007/s10561-019-09767-6. Epub 2019 Apr 24.
Structural bone allografts are often sterilized with γ-irradiation to decrease infection risk, which unfortunately degrades the bone collagen connectivity, making the bone weak and brittle. In previous studies, we successfully protected the quasi-static mechanical properties of human cortical bone by pre-treating with ribose, prior to irradiation. This study focused on the quasi-static and fatigue tensile properties of ribose treated irradiated sterilized bone allografts. Seventy-five samples were cut from the mid-shaft diaphysis of human femurs into standardized dog-bone shape geometries for quasi-static and fatigue tensile testing. Specimens were prepared in sets of three adjacent specimens. Each set was made of a normal (N), irradiated (I) and ribose pre-treated + irradiation (R) group. The R group was incubated in a 1.2 M ribose solution before γ-irradiation. The quasi-static tensile and decalcified tests were conducted to failure under displacement control. The fatigue samples were tested under cyclic loading (10 Hz, peak stress of 45MP, minimum-to-maximum stress ratio of 0.1) until failure or reaching 10 million cycles. Ribose pre-treatment significantly improved significantly the mechanical properties of irradiation sterilized human bone in the quasi-static tensile and decalcified tests. The fatigue life of the irradiated group was impaired by 99% in comparison to the normal control. Surprisingly, the R-group has significantly superior properties over the I-group and N-group (p < 0.01, p < 0.05) (> 100%). This study shows that incubating human cortical bone in a ribose solution prior to irradiation can indeed improve the fatigue life of irradiation-sterilized cortical bone allografts.
结构性骨移植体通常采用γ射线辐照进行灭菌，以降低感染风险，但遗憾的是，这会使骨胶原连接性退化，导致骨头变得脆弱易碎。在之前的研究中，我们通过在辐照前用核糖进行预处理，成功保护了人皮质骨的准静态力学性能。本研究聚焦于经核糖处理的辐照灭菌骨移植体的准静态和疲劳拉伸性能。从人股骨骨干中段切取75个样本，加工成标准化的狗骨形状几何结构，用于准静态和疲劳拉伸测试。样本按三个相邻样本一组进行制备。每组由正常组（N）、辐照组（I）和核糖预处理+辐照组（R）组成。R组在γ射线辐照前在1.2M核糖溶液中孵育。准静态拉伸和脱钙试验在位移控制下进行直至失效。疲劳样本在循环加载（10Hz，峰值应力45MP，最小至最大应力比0.1）下进行测试，直至失效或达到1000万次循环。核糖预处理在准静态拉伸和脱钙试验中显著改善了辐照灭菌人骨的力学性能。与正常对照组相比，辐照组的疲劳寿命受损99%。令人惊讶的是，R组的性能明显优于I组和N组（p<0.01，p<0.05）（>100%）。本研究表明，辐照前将人皮质骨在核糖溶液中孵育确实可以提高辐照灭菌皮质骨移植体的疲劳寿命。
