大鼠自体胸腺肾的功能研究

The functional observation of autologous thymokidney in rats

目的探讨去胸腺成年大鼠自体胸腺在自体肾包膜下血管重建、功能恢复的时间和大鼠外周血T细胞池重建恢复的时间。方法雄性SD大鼠分成4组,Ⅰ：去胸腺组（n=12,体重150～250g）,Ⅱ：自体胸腺肾模型组（n=15,体重150～250g）,Ⅲ：假手术组（n=5,体重50～100g）,Ⅳ：从Ⅰ组中抽取5只在第8周时加去脾脏。通过流式细胞技术和组织形态学来评价胸腺模型中胸腺的血运重建情况及功能。结果Ⅱ组术后2周已见到明显有血管自肾门生长入肾包膜下的胸腺组织中,8周时移植胸腺组织增厚,组织学检查显示正常胸腺组织结构。6周后,Ⅰ组CD4-CD8-T淋巴细胞比例仍持续上升,在Ⅳ组中升高得更明显,而Ⅱ组6周后开始逐渐下降。Ⅰ组CD4＋T和CD8＋T淋巴细胞在术后6周后继续下降,而Ⅱ组开始回升。Ⅰ组CD4＋CD8＋T淋巴细胞在术后6周后仍有波动,后续的检测显示呈低水平,而Ⅱ组6周后较平稳。12～16周后移植的胸腺组织开始逐渐退化。结论大鼠胸腺组织自体肾包膜下移植2周后血运重建良好,术后6周恢复发挥对新生T淋巴细胞选择发育功能;大鼠外周成熟T淋巴细胞的自然扩增对外周血单核细胞（PBMC）中成熟T淋巴细胞数量的维持发挥了重要作用。

Objective We constructed a rat model of stable autologous thymokidney to observe the time required for revascularization and to examine functional recovery of the transplanted tissue and the reconstruction of T-cell reservoirs in peripheral blood mononuclear cells. Methods Male adult Sprague-Dawley rats were divided into 4 groups. Group Ⅰ （n = 12, 150 - 250 g） underwent thymectomy, group Ⅰ （n = 15, 150 - 250 g） received an autologous thymokidney in which thymic tissue was transplanted under the renal capsule, group Ⅰ （n = 5, 50 - 100 g） received sham surgery, and group Ⅳ （n = 5） consisted of rats selected from group I to undergo splenectomy 8 weeks after thymectomy. Revascularization and functional recovery of the transplanted thymuses were evaluated with flow cytometry and histomorphologic examination. Results Two weeks after surgery, blood vessels grew into the renal capsules in group Ⅱ, the transplanted thymic tissue thickened at 8 weeks, and thymic structure was normal. At 6 weeks, numbers of CD4-CD8- T lymphocytes increased in group I and especially in group Ⅳ. A gradual decrease was noted in group Ⅱ. Numbers of CD4＋ and CD8＋ T lymphocytes fluctuated at low levels in group Ⅰ but stayed constant in group Ⅱ. The transplanted thymuses began to gradually degenerate 12 - 16 weeks after surgery. Conclusions Thymuses transplanted under the renal capsules adequately revascularized 2 weeks after surgery, and the autografts began to recover their functions at 6 weeks. Proliferation of peripheral mature T lymphocytes is important in maintaining the number of mature T lymphocytes in peripheral blood mononuclear cells.