基于肠粘膜免疫探究"从肠治肺"治疗COPD小鼠的生物学基础

Our previous work showed that Xuanbai Chengqi Decoction could influence the subtypes of T cells in blood from COPD rats and restore their lung functions. This project is to further investigate the biological mechanism of treating intestine for lung diseases through establishing COPD model on congenic mice. First, investigate the effect of Xuanbai Chengqi Decoction on COPD mice model by analyzing the inflammation in the lung and its function. Second, isolate CD45.2+ immune cells from lamina propria in COPD mice and transfer them into CD45.1+ mice. Analyze the phenotype of CD45.2+ immune cells from the lungs of CD45.1+ mice which will approve whether Xuanbai Chengqi Decoction can restore the mis-homing of intestinal immune cells in COPD mice and find the target immune cell populations. Finally, elaborate the cellular and molecular mechanism of Xuanbai Chengqi Decoction in restoring the mis-homing immune cells by inhibiting the function of target immune cells in vivo as well as analyzing their homing receptors and functions in vitro. These results will further provide newly and reliably biological evidence for "treating intestine for lung diseases" and exploit a new way of thinking on the experimental researches on other "Zang-fu Pairing" theories.

前期相关工作发现宣白承气汤通过影响COPD大鼠外周血T淋巴细胞亚群分布，减轻肺组织损伤。本课题进一步从肠粘膜免疫阐述"从肠治肺"的生物学意义。首先，建立COPD小鼠模型，通过病理切片、real-time PCR检测肺部炎症及肺功能情况，判断宣白承气汤治疗COPD的疗效。其次，利用Congenic小鼠构建COPD模型，分离获得肠粘膜固有层CD45.2+的免疫细胞，并被动转移到CD45.1+小鼠体内，再次运用流式细胞术分析肺部CD45.2+免疫细胞群及表型，证实COPD小鼠肠粘膜固有层免疫细胞错误归巢到肺部，并明确相关靶细胞，同时证实宣白承气汤能纠正这一进程。最后，通过抗体体内阻断实验及体外检测免疫细胞归巢受体及功能的分析，进一步阐述其相关的细胞分子机制。本课题有望阐明"从肠治肺"确切的生物学基础，从而揭示中医理论的科学内涵，同时为其他脏腑相合理论的基础研究提供新思路。

中医“从肠治肺”治则一直指导中医临床肺病的治疗。本项目通过建立COPD和哮喘小鼠疾病模型，探索从肠治肺治则的科学内涵。研究发现COPD小鼠存在肠道菌群的紊乱以及肠免疫病理损伤，而宣白承气汤能纠正COPD小鼠肠道菌群紊乱，抑制肠粘膜固有层Th17的分化，而诱导Treg的分化。尽管COPD小鼠肺肠组织免疫细胞未检测到错误归巢，但宣白承气汤能有效增强COPD小鼠肠源性免疫细胞迁移到肺组织的比例，从而发挥其防治COPD肺部炎性病理的功效。此外，我们还发现哮喘小鼠也存在肠道菌群组成和多样性的降低，且哮喘小鼠肠粘膜固有层ILC2和Th17数量明显增加，从肠治肺方大承气汤可改善哮喘小鼠肠道菌群组成，尤其升高乳酸杆菌的含量，抑制肠组织ILC2的诱生。值得关注的是我们发现哮喘小鼠肺源性免疫细胞能迁移至肠组织以及肠源性免疫细胞迁移到肺部，而大承气汤可增加哮喘小鼠肠源性免疫细胞迁移到肺部的数量。这为中医“肺病及肠”，以及“从肠治肺”提供了可靠的科学依据，从而为肺合大肠理论在中医临床的使用提供了坚实的实验依据，也为其他脏腑相合理论的基础研究提供新思路。