牛附植前胚胎获得耐热的MAPK信号调控机制

热应激对动物生殖影响日益凸显，成为现今国际研究热点。申请者前期研究表明，牛附植前胚胎耐热力随发育而增加，但在胚胎发育的哪个阶段、如何获得耐热及其细胞信号转导机制尚不清楚。本研究以牛附植前胚胎发育获得耐热并有遗传差异为理论假说，从附植前胚胎不同发育阶段（合子-囊胚）入手，以胚胎热激反应（抗氧化、凋亡和合成调节分子）及MAPK信号调控（信号激活及其调控）为研究切入点，以牛（3个品种）体外受精的胚胎为实验对象，利用发育生物学、分子生物学和细胞生物学等研究手段，观察热应激时胚胎遗传基因差异表达、MAPK信号通路中关键因子（JNK、p38和ERK1/2）表达、氧化还原状态、凋亡与抗凋亡平衡、调节分子（HSPs和IGF-1）的动态变化，分析其与胚胎发育获得耐热的相关性，找出胚胎发育获得耐热的遗传因素，揭示MAPK信号激活时期及其转导机制，为阐明热应激影响动物生殖机理和预防夏季奶牛不孕提供理论依据。

Heat stress disrupting animal reproduction which has been becoming more and more prominent is an increasingly hotspot of international research in nowadays. Our previous research confirmed that deleterious effects of heat shock on bovine preimplantation embryos become attenuated as development proceeds. However, neither at which stage and how the embryos gain their resistance to heat stress nor signal transmission mechanism involved in the process is clear. We hypothesize that bovine preimplantation embryos gain thermotolerance as development to advanced stage which varies genetically. In vitro derived embryos from three breeds of cow in their various preimplantation development stages (zygote to blastocyst) will be used to study the embryonic response (antioxidation, apoptosis and production of cytoprotective molecules) to heat stress and the regulating mechanism of MAPK signal transmission as well as genetic variation in acquired thermotolerance of bovine preimplantation embryos subject to elevating temperature using advanced technologies in modern developmental biology, molecular biology and cytobiology. Dynamic changes in genetic gene differential expression, the key molecules（JNK, p38 and ERK1/2）expression in the MAPK signal pathway, embryonic redox state, apoptosis and antiapoptosis equilibrium, as well as the cytoprotective molecules (HSPs and IGF-1) will be monitored in the study. The correlations between these measured indicators and embryo thermotolerance will be analyzed to reveal the genetic factors, the development stage when MAPK activates and its signal transmission mechanism in embryo developmental gained thermotolerance. The results will provide a theoretic base for revealing the mechanism of heat stress disrupting animal reproduction and preventing summer infertility of dairy cows.