体外培养的人胸腺组织移植到裸鼠不同部位后的免疫重建效果分析

Immune reconstitution efficacy of human thymic slices transplanted to different parts of nude mice

目的通过分析人胸腺组织切片移植到裸鼠肾包膜,皮下和股四头肌后的免疫重建效果,探究胸腺组织异位移植的最佳位置。方法收集先天性心脏病患者手术废弃的胸腺组织,制作成0.5~1 mm厚的组织切片,体外培养以清除免疫细胞。利用H&E染色、免疫组织化学染色和定量PCR等方法评估组织切片中残余的组织结构、细胞类型和功能。最后将胸腺组织切片分别移植入裸鼠的肾包膜、皮下和股四头肌3个部位,并通过流式细胞术和组织学检测等手段比较3个部位移植后的免疫重建效果。结果体外培养14 d的胸腺组织切片中T淋巴细胞的清除率达90%以上,上皮细胞网状结构保存完整,残存大量的巨噬细胞、树突状细胞、内皮细胞。定量PCR结果显示,体外培养能有效维持胸腺组织切片中上皮细胞标志物及其分泌细胞因子的基因表达量。流式细胞术显示移植后16周,不同移植组小鼠外周血中T细胞的比例均显著增加,其中股四头肌移植组小鼠的T细胞比例最高。原位组织学检测显示,移植物在3个部位均能检出胸腺组织再生。但是肾包膜组移植物检出率为40%,皮下组移植物检出率为60%,股四头肌组移植物检出率为100%。结论体外培养14 d的胸腺组织切片保留了完整的胸腺基质微环境,移植人的胸腺组织切片后可有效重建裸鼠的T细胞比例,且股四头肌部位移植的效果优于肾包膜和皮下部位。

This study was designed to explore the immune reconstitution efficacy of human thymic slices transplanted into renal capsule,subcutaneous or muscle of nude mice,and further explore the optimal location of heterotopic transplantation.The thymus tissue discarded from congenital heart disease patients was made into 0.5-1 mm thick tissue sections and cultured in vitro to remove immune cells.H&E staining and immunohistochemical staining were used to assess the residual tissue structure and cell types in thymic slices,while quantitative PCR methods were used to assess the function of residual cells in thymic slices.Then thymic slices were transplanted into the renal capsule,subcutaneous or muscle of nude mice,and the immune reconstitution efficacy was compared by flow cytometry and histology.Data showed that after 14 days of culture in vitro,the clearance rate of T lymphocytes in the thymic slices was more than 90%,and the epithelial cell network structure of the tissue was intact,while a large number of macrophages,dendritic cells and endothelial cells remained.Quantitative PCR results showed that the gene expression levels of epithelial cell markers and secreted cytokines in cultured thymic slices could be effectively maintained.Flow cytometry showed that at 16 weeks after transplantation,the proportion of T cells in peripheral blood of mice in different transplantation groups were significantly increased,whereas the proportion of T cells in muscle group was the highest.In situ histological examination showed that the regeneration of thymus tissue was detected at all three transplant sites.In addition,the graft detection rate was 40%in the renal capsule group,60%in the subcutaneous group and 100%in the musclegroup.In conclusion,the human thymic slices cultured in vitro for 14 days retain a complete thymic matrix microenvironment.Transplantation of human thymic slices can effectively reconstruct the ratio of T cells in nude mice,and the muscle is the most effective transplantation site.