Time-lapse imaging and software to monitor and predict embryonic health and viability

加拿大养牛业每年通过直接和间接收入创造超过400亿美元的收入。加拿大的乳制品行业是国民经济的主要驱动力，是该国最大的农业食品行业之一，加拿大的红肉和牲畜出口是世界上最高的。为了保持这种竞争优势，改进生殖生物技术是必不可少的，因为它们确保了种质资源的更快繁殖以及更高的生产力。******今天牛胚胎学家面临的最大问题是，我应该把哪个胚胎移植回牛体内，或者哪个胚胎应该被指定保存，这样它就足够强壮，可以面对低温保存的困难和严酷？不幸的是，这个问题仍然没有明确的答案。传统的胚胎选择方法仍然依赖于形态评估，这一过程仍然与牛早期胚胎失败和生产力损失的较高水平有关。侵入性的胚胎选择方法，如胚胎活检、胚胎核型分析等已经得到了评估，但它们对改善选择过程的影响仍然存在高度争议。******最近开发了一种新的胚胎选择方法，该方法将形态学评估与卵裂动力学相结合，该方法通过非侵入性方法评估特定事件的时间，如原核形成，合体，早期卵裂事件，细胞周期间隔，细胞分裂的同步性和囊胚形成的起始。这是通过将胚胎培养在具有自己的延时成像系统的个性化腔室中完成的，以便可以监测和记录每个形态发生事件（卵裂，桑葚胚形成，囊胚形成）的时间，并可以分析每个胚胎这些事件之间的时间（卵裂间隔）。该技术在人类实验室的应用已经取得了非常有希望的结果，然而，该技术尚未应用于牛胚胎的评估。我们打算成为世界上第一个使用这种仪器对牛胚胎进行评估和测试的实验室，如果我们可以选择胚胎的发育能力、生存能力和健康。因此，本提案的目的是提高目前对牛体外受精实验室延时监测的理解，并讨论关于形态动力学作为牛囊胚形成、胚胎活力和发育能力的预测方法的证据。**

Canadian cattle industry generates over $ 40 billion annually, through direct and indirect revenue. While the Canadian dairy industry is a key driver of our national economy and represents one of the largest agri-food industries in the country, Canada's export of red meat and livestock is the highest in the world. To maintain this competitive edge, improvements in the reproductive biotechnologies are imperative as they ensure faster multiplication of germplasm as well as higher productivity. ******The biggest question facing bovine embryologists today is, which embryo should I transfer back into a cow or which embryo should be assigned for preservation so that it is robust enough to face the hardship and rigours of cryopreservation? Unfortunately, there is still no definite answer for this question. Conventional methods of embryo selection are still dependent on morphological evaluation and this procedure is still related to higher levels of early embryonic failures and productivity losses in cattle. Invasive methods of embryo selection like embryo biopsy, embryo karyotyping etc. have been evaluated but their effect on improving the selection process is still highly debated. ******A new method of embryo selection, which combines assessment of morphology with cleavage kinetics has been recently developed and this method banks on assessing the timing of specific events such as pronuclear formation, syngamy, early cleavage events, cell cycle intervals, synchronicity of cell division and initiation of blastocyst formation through a non-invasive approach. This is done by culturing embryos in a personalized chamber with its own time-lapse imaging system so that timing of each morphogenetic event (cleavage, morula formation, blastocyst formation) can be monitored, documented and timing between these events (inter-cleavage intervals) can be analysed for each embryo. Application of this technique in human labs has yielded very promising results however, such a technique has not been applied for evaluation of bovine embryos as yet. We intend to be the first lab in the world to use this apparatus for bovine embryo evaluation and test if we can select embryos for their developmental competence, viability and health. The aim of this proposal therefore is to improve the current understanding of time-lapse monitoring in a bovine IVF laboratory and to discuss the evidence regarding morpho-kinetics as a predictive method for blastocyst formation, embryo viability and developmental competence in bovine. **