Serum exosomes protect heat-stressed mouse 2-cell embryos: Enhanced antioxidant defense and base excision repair of oxidative DNA damage.

High temperatures pose a significant threat to human health; however, there are limited measures to address infertility resulting from elevated temperatures. This study aimed to evaluate the protective effects of exosomes on heat-stressed mouse 2-cell Embryos. The results indicated that exposure to high environmental temperatures caused substantial damage to the developmental potential of embryos, while the inclusion of serum exosomes during early pregnancy demonstrated a beneficial impact. Specifically, high environmental temperatures lead to embryonic retardation and increase oxidative stress levels in embryos. The introduction of exosomes significantly enhances the antioxidant capacity and the efficiency of the base excision repair (BER) pathway in heat-stressed embryos, reduces DNA oxidative damage, and decreases the level of cell apoptosis in these embryos. Furthermore, exosomes can enhance embryo development rates by increasing the number of trophoblast cells and the diameter of the blastocyst, while also boosting the expression of genes involved in blastocyst lineage differentiation. This research offers novel strategies to improve pre-implantation embryo heat tolerance and mitigate high-temperature damage, providing new insights for optimizing embryo development in human assisted reproductive technologies.