Kaminski Artur, Jastrzebska Anna, Grazka Ewelina, Marowska Joanna, Gut Grzegorz, Wojciechowski Artur, Uhrynowska-Tyszkiewicz Izabela
Department of Transplantology and Central Tissue Bank, Medical University of Warsaw, Warsaw, Poland.
Cell Tissue Bank. 2012 Aug;13(3):363-74. doi: 10.1007/s10561-012-9308-2. Epub 2012 Apr 27.
The secondary sterilisation by irradiation reduces the risk of infectious disease transmission with tissue allografts. Achieving sterility of bone tissue grafts compromises its biomechanical properties. There are several factors, including dose and temperature of irradiation, as well as processing conditions, that may influence mechanical properties of a bone graft. The purpose of this study was to evaluate the effect of gamma irradiation with doses of 25 or 35 kGy, performed on dry ice or at ambient temperature, on mechanical properties of non-defatted or defatted compact bone grafts. Left and right femurs from six male cadaveric donors aged from 46 to 54 years, were transversely cut into slices of 10 mm height, parallel to the longitudinal axis of the bone. Compact bone rings were assigned to the eight experimental groups according to the different processing method (defatted or non-defatted), as well as gamma irradiation dose (25 or 35 kGy) and temperature conditions of irradiation (ambient temperature or dry ice). Axial compression testing was performed with a material testing machine. Results obtained for elastic and plastic regions of stress-strain curves examined by univariate analysis are described. Based on multivariate analysis it was found that defatting of bone rings had no significant effect on any mechanical parameter studied, whereas irradiation with both doses decreased significantly the ultimate strain and its derivative toughness. The elastic limit and resilience were significantly increased by irradiation with the dose 25 kGy, but not 35 kGy, when the time of irradiation was longer. Additionally, irradiation at ambient temperature decreased maximum load, elastic limit, resilience, and ultimate stress. As strain in the elastic region was not affected, decreased elastic limit resulted in lower resilience. The opposite phenomenon was observed in the plastic region, where in spite of the lower ultimate stress, the toughness was increased due to the increase in the ultimate strain. The results of our study suggest that there may be an association between mechanical properties of bone tissue grafts and the damage process of collagen structure during gamma irradiation. This collagen damage in cortical bone allografts containing water does not depends on the temperature of irradiation or defatting during processing if dose of gamma irradiation does not exceed 35 kGy.
通过辐照进行二次灭菌可降低同种异体组织移植传播传染病的风险。实现骨组织移植物的无菌状态会损害其生物力学性能。有几个因素，包括辐照剂量和温度以及处理条件，可能会影响骨移植物的力学性能。本研究的目的是评估在干冰上或常温下进行的25或35千戈瑞剂量的伽马辐照对未脱脂或脱脂密质骨移植物力学性能的影响。将来自6名年龄在46至54岁之间的男性尸体供体的左右股骨沿与骨的纵轴平行的方向横向切成10毫米高的薄片。根据不同的处理方法（脱脂或未脱脂）、伽马辐照剂量（25或35千戈瑞）以及辐照温度条件（常温或干冰），将密质骨环分配到八个实验组。使用材料试验机进行轴向压缩测试。描述了通过单变量分析检查的应力 - 应变曲线的弹性和塑性区域获得的结果。基于多变量分析发现，骨环脱脂对所研究的任何力学参数均无显著影响，而两种剂量的辐照均显著降低了极限应变及其衍生的韧性。当辐照时间较长时，25千戈瑞剂量的辐照显著提高了弹性极限和弹性模量，但35千戈瑞剂量的辐照未达到此效果。此外，常温下辐照降低了最大载荷、弹性极限、弹性模量和极限应力。由于弹性区域的应变未受影响，弹性极限降低导致弹性模量降低。在塑性区域观察到相反的现象，尽管极限应力较低，但由于极限应变增加，韧性增加。我们的研究结果表明，骨组织移植物的力学性能与伽马辐照期间胶原结构的损伤过程之间可能存在关联。如果伽马辐照剂量不超过35千戈瑞，含有水分的皮质骨同种异体移植物中的这种胶原损伤不取决于辐照温度或处理过程中的脱脂情况。
