Lu Tao, Huang Yiwei, Qiao Yulei, Zhang Yongxing, Liu Yu
Department of Thoracic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
Eur J Cardiothorac Surg. 2021 Jan 4;59(1):155-161. doi: 10.1093/ejcts/ezaa314.
Little is known on the outcome of tracheal allografts after long-term survival. This study aimed to explore the changes in structure and composition by evaluating the status of the mucosa and cartilage of allografts with long-term survival in dogs.
Eight tracheal allografts that survived for ˃9 months were enrolled in our study. Epithelium, revascularization, monocyte infiltration and fibrosis were evaluated histologically. The fluorescent dye 4'-6-diamidino-2-phenylindole was used to evaluate the presence of chondrocyte nuclei. Glycosaminoglycan was detected using safranin-O staining and collagen II was evaluated using immunohistochemistry.
The 8 animals survived from 277 to 783 days. Bronchoscopy demonstrated that 6 allografts showed no stenosis; 2 cases developed slight stenosis, but could maintain airway patency. Histological examination showed that the epithelium covered the surface of the allografts. In comparison to fresh tracheal controls, allografts demonstrated mild monocyte infiltration, evident revascularization and mild fibrosis in the mucosa or submucosa (all P < 0.05). There were a few viable chondrocytes scattered in the cartilage after long-term survival. Moreover, glycosaminoglycan and collagen II were significantly decreased in the allografts compared with fresh trachea (all P < 0.05).
For tracheal allografts with long-term survival after transplantation, only a few viable chondrocytes were retained, and the extracellular matrix of the cartilage demonstrated degeneration. Despite this, the airway could maintain patency. Notably, the significance of monocyte infiltration in the mucosa or submucosa at different time points warrants further study.
关于气管同种异体移植长期存活后的结果，我们了解甚少。本研究旨在通过评估长期存活的犬气管同种异体移植的黏膜和软骨状况，探索其结构和成分的变化。
8个存活超过9个月的气管同种异体移植纳入本研究。通过组织学评估上皮、血管再生、单核细胞浸润和纤维化情况。使用荧光染料4′-6-二脒基-2-苯基吲哚评估软骨细胞核的存在情况。采用番红O染色检测糖胺聚糖，并用免疫组织化学法评估Ⅱ型胶原。
8只动物存活277至783天。支气管镜检查显示，6个同种异体移植无狭窄；2例出现轻度狭窄，但可维持气道通畅。组织学检查显示，上皮覆盖同种异体移植表面。与新鲜气管对照相比，同种异体移植显示黏膜或黏膜下层有轻度单核细胞浸润、明显的血管再生和轻度纤维化（均P<0.05）。长期存活后，软骨中有少量存活的软骨细胞散在分布。此外，与新鲜气管相比，同种异体移植中的糖胺聚糖和Ⅱ型胶原显著减少（均P<0.05）。
对于移植后长期存活的气管同种异体移植，仅保留了少量存活的软骨细胞，软骨的细胞外基质出现退变。尽管如此，气道仍可维持通畅。值得注意的是，黏膜或黏膜下层不同时间点单核细胞浸润的意义值得进一步研究。
