根据指导方针,处理时同种异体移植物的总缺血时间必须保持较短,以避免变性。由于实际无法在时限内完成从采购到冷冻保存的所有步骤,许多同种移植物被丢弃。虽然,多项研究表明,缺血时间延长的同种异体移植物显示出足够的质量和性能。收集20个主动脉和12个肺同种异体移植物,并在准备时(第0天)和在4°C下进行抗生素去污后1、2、3、4、7、14、21、28和60天取回活检。制备用于光学显微镜(LM)和透射电子显微镜(TEM)的活检组织。评估生成的细胞分数,弹性蛋白,和胶原蛋白。使用Wilcoxon符号秩检验比较时间之间的相对差异。Bonferroni校正的p值0.0056被认为是显著的。LM只能显示主动脉同种异体移植物在60天的细胞计数减少,未检测到其他差异.TEM显示主动脉和肺同种移植分别在第3天和第4天及以后受影响的细胞外观。主动脉和肺同种移植在第21天的弹性蛋白外观受到影响。在第28天,同种异体主动脉移植物的胶原外观受到影响,肺同种异体移植没有显着差异。取得同种移植后早期开始细胞变性,但是弹性纤维和胶原纤维更能抵抗变性。LM中的整体结构完整性完全没有受到影响,而透射电镜可以分别在21天和28天显示单个弹性纤维和胶原蛋白束中的小变性迹象。
According to
guidelines, total ischemic time for homografts at processing must be kept short to avoid degeneration. Many homografts are discarded due to practical inability to finish all steps from procurement to cryopreservation within the time limit. Although, several studies have shown that homografts with prolonged ischemic time show adequate quality and performance. Twenty aortic and 12 pulmonary homografts were collected and biopsies were retrieved at preparation (day 0) and after 1, 2, 3, 4, 7, 14, 21, 28, and 60 days in antibiotic decontamination at 4 °C. Biopsies were prepared for light microscopy (LM) and transmission electron microscopy (TEM). Assessment generated scores for cells,
elastin, and collagen. Relative differences between times were compared with Wilcoxon signed rank test. Bonferroni corrected p value of 0.0056 was considered significant. LM could only reveal decrease in cell count at 60 days in aortic homografts, no other differences was detected. TEM showed affected cell appearance in day 3 and day 4 and beyond for aortic and pulmonary homografts respectively.
Elastin appearance was affected at day 60 for aortic and day 21 for pulmonary homografts. Collagen appearance was affected at day 28 for aortic homografts, with no significant differences in pulmonary homografts. Cell degeneration starts early after homograft procurement, but elastic and collagen fibers are more resistant to degeneration. Overall structure integrity as seen in LM was not affected at all, while TEM could reveal small degeneration signs in individual elastic fibers and collagen bundles at 21 and 28 days respectively.