社会转型期巨大的工作和生活压力带来的心理应激是我国近年来不孕不育率迅速上升的主要原因之一。正常妊娠不仅取决于正常发育的胚胎，也需要适宜胚胎种植的着床环境。当前应激抑制生殖的研究多集中在对卵泡和胚胎发育的影响，缺乏应激影响子宫着床环境的研究。在综合文献及前期课题研究基础上，我们提出心理应激可通过下调CD4＋CD25＋Treg细胞干扰胚胎着床。本研究将采用经典的天敌暴露心理应激模型，观察心理应激对胚胎着床、CD4＋CD25＋Treg细胞比例和相关细胞因子水平的影响；体外诱导的CD4＋CD25＋Treg细胞将被过继输注到应激小鼠以验证其作用；单向混合淋巴细胞培养体系用于观察应激小鼠Treg细胞功能。我们还将观察Treg细胞在心理应激干扰胚胎着床中的作用是否与雌、孕激素相关。研究旨在阐明CD4＋CD25＋Treg细胞在心理应激干扰胚胎着床中的作用及机制，有望为应激相关不孕症的临床治疗提供新思路。

Psychological stress induced by enormous pressure of work and life is one of the prime reasons to cause rapid increase of infertility rate in the period of social transition in China today. A successful pregnancy is decided by both good-quality embryo and favorable endometrial environment for implantation. Researches on the mechanism of stress-induced repression of reproduction focused on the development of follicles and embryos. little is known about the endometrial environment for implantation. On the basis of literature review and our preliminary studies, we proposed that psychological stress may disturb embryo implantation by down-regulation of CD4＋CD25＋Treg cells. A classic psychological stress induced by predatory stress is going to be used. We will observe the effect of psychological stress on embryo implantation、the percentage of CD4＋CD25＋Treg cells and the level of related cytokines, including IL-2, INF-γ,TNF-α,IL-10 and TGF-β. To validate the role of CD4＋CD25＋Treg cells, induced CD4＋CD25＋Treg cells are adoptively transferred into stressed mice. One-way mixed lymphocytes culture is used to observe the function of CD4＋CD25＋Treg from stressed mouse. We are going to observe if the down-regulation of CD4＋CD25＋Treg cells by psychological stress is associated with E2 and P4 through supplement with full dose of E2 and P4. The study would help to clarify the role and mechanisms of CD4＋CD25＋Treg cells in the process of implantation repression induced by psychological stress, which is intended to provide a new idea in the therapy of stress-associated infertility and repeated implantation failure.