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。虽然加拿大乳制品行业是我国国民经济的关键驱动力，是该国最大的农业食品行业之一，但加拿大的红肉和牲畜出口是世界上最高的。为了保持这一竞争优势，生殖生物技术的改进势在必行，因为它们确保了种质的更快繁殖和更高的生产率。*今天牛胚胎学家面临的最大问题是，我应该将哪个胚胎移植回奶牛体内，或者应该指定哪个胚胎进行保存，以便它足够健壮，以应对冷冻保存的困难和严酷？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。有创伤性的胚胎选择方法如胚胎活检、胚胎核型分析等已被评估，但它们在改进选择过程中的作用仍存在很大争议。最近发展了一种新的胚胎选择方法，它结合了形态和卵裂动力学的评估，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、联配、早期分裂事件、细胞周期间隔、细胞分裂的同步性和囊胚形成。这是通过在带有自己的延时成像系统的个性化小室中培养胚胎来实现的，以便可以监测、记录每个形态发生事件(卵裂、桑椹形成、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(卵裂间间隔)。这项技术在人类实验室中的应用已经取得了非常有希望的结果，然而，这种技术还没有被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设备对牛胚胎进行评估和测试的实验室，如果我们能根据胚胎的发育能力、活力和健康来选择胚胎的话。因此，这项建议的目的是提高目前对牛体外受精实验室中时间推移监测的理解，并讨论形态动力学作为预测牛胚泡形成、胚胎活力和发育能力的证据。**

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. **