母体营养缺乏导致的胎儿宫内生长受限（IUGR）是一种普遍现象，它严重阻滞胎儿胸腺生长发育并引发胸腺微环境的程序性改变而导致胸腺T淋巴细胞发育分化受阻、细胞免疫缺陷，但机理仍不很清楚。因此，本项目拟通过分析IUGR影响绵羊胎儿胸腺生长发育、组织结构及胸腺微环境程序性改变的一般规律，测定IUGR胎儿胸腺细胞外生长因子及其受体表达和表观遗传修饰变化，明确IUGR调控胎儿胸腺微环境程序性改变主效信号通路及其相互关系，研究IUGR胎儿胸腺微环境程序性改变主效信号通路调控T淋巴细胞发育分化机理，从器官、细胞和分子的不同层次系统揭示IUGR绵羊胎儿胸腺细胞外生长因子及其受体-胸腺微环境程序性改变信号通路-T淋巴细胞发育三位一体的分子调控信号网络，阐明IUGR绵羊胎儿胸腺微环境程序性改变及其阻滞T淋巴细胞发育分子机理，为建立北方草原地区冬春季节合理科学的饲养管理制度及医学相关研究提供一定的参考依据。

Intrauterine growth restriction (IUGR) caused by maternal undernutrition is a relatively common condition, which severely restrict the growth of fetal thymus, induce programming modifications of fetal thymic microenvironment, and result in retardation of intrathymic T lymphocyte development and deficiency of cellular immunity. However, the mechanisms remain unclear. Therefore, this study intends to analyze the effects of IUGR on growth and development of fetal thymus, thymic structure and the programming modifications of Mongolian ovine fetal thymic microenvironment, measure the concentrations of extracellular growth factors, the gene expressions and epigenetic modifications of their receptors in IUGR ovine fetal thymus, determine main cell signaling pathways manipulating the programming modifications of ovine fetal thymic microenvironment and their relationships, investigate the retarding mechanisms of the main cell signaling pathways in programming modifications IUGR fetal thymic microenvironment to the development and differentiation of intrathymic T lymphocyte, in order to reveal the trinity molecular signal network of extracellular growth factors and their receptors - Regulating signaling pathways in programming modifications of fetal thymic microenvironment - Intrathymic T lymphocyte development, and clarify molecular mechanisms underlying the programming modifications of thymic microenvironment and retardation of intrathymic T lymphocyte development in IUGR Mongolian ovine fetuses, supply references for scientific feeding and management during the winter-spring grazing season of north China as well as the researches correlated in medical science.