母体密度应激对子代根田鼠HPA轴的程序化效应及其表观遗传机制

Maternal density stress reduces offspring immunity and reproduction through the programming effect of the HPA axis of offspring. Assuming that this programming effect is achieved through the epigenetic mechanism of offspring, it will provide important evidence for the molecular regulation mechanism of the small mammalian population. We will establish high density and low density enclosed populations of root voles (Microtus oeconomus) in Haibei Research Station of Alpine Meadow Ecosystem. Parent and F1 offspring’s faecal corticosterone metabolites (FCM) and their negative feedback function of the HPA axis will be measured; and the relationship between FCM and reproductive parameters of the population will be investigated. We analyze CRH gene and NR3C1 mRNA expression and its promoter methylation level from the perspective of epigenetics and test the hypothesis of maternal density stress can influence the CRH gene and NR3C1 mRNA expression and the promoter methylation level of the offspring by affecting the negative feedback function of the parent HPA axis, and then make the programming effect of the offspring HPA axis. Our aim is to answer the scientific question of whether maternal density stress worsens the functional properties of the offspring HPA axes through epigenetic mechanisms, expecting firstly establish the methods of the epigenetic mechanism of maternal density stress on the programming effect of the offspring HPA axis under natural conditions, and ultimately, contributing to the automatic regulation of populations at the molecular level for maternal effects.

母体密度应激可通过对子代HPA轴的程序化效应降低子代免疫和繁殖。假设该程序化效应是通过子代表观遗传机制来实现的，那么将为小哺乳动物种群分子调节机制提供重要证据。本研究将在青藏高原高寒草甸地区，以根田鼠为对象，在野外围栏条件下，分别建立亲本高密度和低密度种群，测定亲本和子代的粪便皮质酮含量及HPA轴负反馈功能，探讨粪便皮质酮与种群繁殖参数间的关系，从表观遗传角度分析CRH基因和NR3C1mRNA表达及其启动子区甲基化水平，检验母体密度应激可通过影响亲本HPA轴负反馈功能而影响子代CRH基因和NR3C1mRNA表达及其启动子区甲基化水平，继而使子代HPA轴产生程序化效应的假设，目的在于回答母体密度应激是否通过表观遗传机制恶化子代HPA轴功能特性的科学问题，以期首先在自然条件下建立母体密度应激对子代HPA轴程序化效应的表观遗传机制的研究方法，最终为母体效应在分子水平上对种群自动调节作出贡献。

母体密度应激可通过对子代HPA轴的程序化效应降低子代免疫和繁殖。假设该程序化效应是通过子代表观遗传机制来实现的，那么将为小哺乳动物种群分子调节机制提供重要证据。本研究将在青藏高原高寒草甸地区，以根田鼠为对象，在野外围栏条件下，分别建立亲本高密度和低密度种群，测定了亲本和子代的粪便皮质酮含量及HPA轴负反馈功能，探讨了粪便皮质酮与种群繁殖参数间的关系，从表观遗传角度分析了CRH基因和NR3C1mRNA表达及其启动子区甲基化水平，回答了母体密度应激可通过表观遗传机制恶化子代HPA轴的功能特性的科学问题，在自然条件下建立了母体密度应激对子代HPA轴程序化效应的表观遗传机制的研究方法；此外，本研究还测定了子代的免疫参数并探讨了子代肠道菌群的变化，进一步探讨了免疫参数和肠道菌群的变化可能会在种群调节中的作用，最终为母体效应在分子水平上对种群自动调节作出贡献。