腹主动脉瘤是常见的高度致死性的大血管疾病。慢性炎症反应在腹主动脉瘤的发生发展中起重要作用。炎性细胞及细胞因子构成的微环境是慢性炎症持续存在的基础。研究表明IL-17及IL-17相关免疫细胞在炎性微环境的调控中发挥重要作用，参与多种炎性疾病发生发展，但其在腹主动脉瘤中的作用尚不明确。我们前期研究结果证实拮抗IL-17特异性转录因子RORγt活性可抑制Th17/IL-17反应，减缓小鼠实验性腹主动脉瘤的进展，但RORγt与腹主动脉瘤的深层次关系仍未得知，其机制有待进一步研究。本课题将利用基因敲除、细胞过继性输注、细胞抗体阻断等方案联合体外实验，探讨干预RORγt对固有淋巴细胞、γδT细胞、巨噬细胞及传统辅助T细胞的影响，明确其在炎症微环境中的调节机制和腹主动脉瘤中的作用机制，为腹主动脉瘤的临床治疗提供新的思路。

Abdominal aortic aneurysm (AAA) is a common and fatal vascular disease among the population in most countries. The chronic inflammatory responses play a key role in the progression of AAA. The microenvironment consisted of inflammatory cells and factors forms the basis for the persistent existence of chronic inflammation. Numerous studies show that IL-17 and its related immune cells are instrumental in the regulation of inflammatory microenvironment, and involved in many inflammatory diseases. However, the effect on AAA is still unclear. Our previous research work has indicated that antagonizing the activity of RORγt, the specific transcription factor of IL-17, confers protection against experimental abdominal aortic aneurysm via inhibiting the Th17/IL-17-related inflammatory responses. However, the deeper mechanism of RORγt in AAA lesions is still unknown, and further research work is needed. To fully explore the effect of RORγt in ILC3s (group3 innate lymphoid cells), γδT cells and traditional T lymphoid cells, the double gene knock-out mice, adoptive cell transfer, cell depletion with antibody and vitro cell experiments are used in this study. Moreover, this project will further elucidate the mechanism of RORγt in IL-17-related inflammatory microenvironment, and in the progression of AAA. This study may provide a novel strategy for non-surgical AAA treatment.