供体犬移植段气管的最佳获取时间

目的 探讨热缺血对移植体存活的影响，寻求获取供体气管的可靠时间。方法 选用杂种犬进行同种异体气管移植。供犬处死后经过不同热缺血时间取出气管，TUNEL法检测软骨细胞凋亡。各移植体植入受犬的气管原位及腹腔大网膜内，4周后处死取材。行病理学检查。并比较各组移植体软骨细胞存活率。结果 随着热缺血时间的延长，移植体软骨细胞凋亡数逐渐增加，移植后软骨结构破坏加重。并且相同热缺血期移植体，异位移植较原位移植结构保持好。结论 气管移植体对热缺血有较好的耐受，但是长时间的热缺血仍会给气管移植体带来损害。

The best time of harvesting canina allograft tracheal

Objective To investigate the effect of warm ischemic time on the viability of nonheartbeating cadaveric tracheal allograft,and to evaluate the reliable limit of warm ischemic time before harvested from the cadaver.Methods The tracheal allografts from donor mongrel dogs were harvested at different warm ischemic time points from cardiac death (0,2,4 and 12 h after circulatory arrest,each group n=6).Part specimens were conducted to detect and quantify the chondrocyte apoptosis of cartilaginous ring by using fluorescent in situ end labeling of DNA fragments (TUNEL assay).Every tracheal allograft was splited to two five-ring allografts:One of them was transplanted orthotopically to the cervical portion of the trachea and covered with an omental pedicle,and another was heterotopically implanted into the omentum.The animals were sacrificed on postoperative 4 weeks,and the postmortem specimens were examined grossly and histologically.Viable chondrocyte ratio of the grafts in every group was assessed.Results As the warm ischemic time was prolonged,chondrocyte apoptotic index of the grafts was increased,the structureof cartilge was destroyed more seriously after transplanted,and the viable chondrocyte ratio decreased.More excellent preservation of tracheal structure and morphology was achieved in heterotopically transplanted grafts than in orthotopically transplanted grafts at the same warm ischemic time.Conclusion The tolerable warm ischemic time of the trachea was long.But a prolonged ischemic time had an irreversible deteriorative effect on the graft though their structure was intact when examined by a microscope.Two-stage tracheal transplantation may be more feasible for allograft harvested from the cadaver.