Astaxanthin promotes in vitro maturation of mouse oocytes by regulating mitochondrial functions and protein homeostasis†.

The quality of mouse oocytes that are matured in vitro is much lower than the ones that are matured in vivo. This difference is mainly due to oxidative stress occurring in culture conditions. Astaxanthin, a marine carotenoid, is one of the most robust natural antioxidants that can effectively reduce oxidative stress. However, the role of astaxanthin in oocyte in vitro maturation (IVM) has not been reported. Here, we showed that the addition of astaxanthin successfully increased the maturation rate of mouse IVM oocytes. Single-cell transcriptome sequencing showed that the differential genes were mainly enriched to mitochondrial functions and protein homeostasis. By using micro-proteomics, we further showed that the mitochondrial activity was enhanced by astaxanthin addition. To reveal the developmental competence of astaxanthin-treated IVM oocytes and conquer the zona pellucida hardening, we applied zona pellucida laser optoperforation to assist the in vitro fertilization. We found that the 2-cell embryo rate was significantly increased in astaxanthin-treated oocytes. In summary, this study reveals that astaxanthin can efficiently promote mouse oocyte IVM and early embryonic development.