Autophagic activity as an indicator for selecting good quality embryos

Is it possible to predict the quality of embryos that appear to be morphologically identical when viewed under a microscope? Thirty-five years have passed since the world’s first human birth from in vitro fertilization. While the dissemination of assisted reproduction technologies during this time has been remarkable, the evaluation of embryo quality in both humans and mice currently relies entirely on morphological observation. More efficient infertility treatments will likely be possible if high-quality embryos can be selected by screening. To develop a novel quality evaluation method that does not rely on morphology, we focused on autophagy, one of the molecular mechanisms essential for the early embryonic development. Autophagy is a massive cytoplasmic degradation pathway mediated by the lysosome. Our previous studies have demonstrated that fertilization-induced autophagy is essential for preimplantation embryonic development. This autophagy is thought to supply the nutrients and amino acids necessary for maintaining subsequent embryo development, through the bulk degradation of maternal cytoplasmic factors that are accumulated during oogenesis. Here, we briefly summarize autophagy and its physiological function, and describe a recently developed method for using autophagic activity as an indicator to predict embryo quality.