Microtubule Integrity Is Associated with Mitochondrial Function and Quality of Murine Preimplantation Embryos

Poor embryo quality is a major cause of poor clinical outcomes in assisted reproductive medicine, and there are no currently available interventions that can improve embryo quality. Mitochondria dysfunction is linked to low-quality female gametes and zygotes. Previously, microtubule integrity was also associated with mitochondrial function in oocytes. In the present study, we investigated the effects of the microtubule stabilizers (MTS) Taxol and Epothilone D and the microtubule disturber (MTD) vinorelbine on mouse preimplantation embryo quality and pregnancy outcome. We prepared young BDF1 mice (7~9 weeks old) and cultured preimplantation embryos with MTS or MTD. Mitochondrial functional activity and embryo development ratios including pregnancy ratios were then assessed. MTS-treated embryos showed significantly increased mitochondrial membrane potentials and motility. Blastocyst formation was significantly higher in MTS-treated embryos than in MTD-treated embryos. Especially, MTS-treated embryos exhibited higher hatched blastocyte formation than untreated embryos. The number of offspring was significantly higher in surrogate mice transplanted with MTS-treated embryos. These findings demonstrated that treatment of mouse preimplantation embryos with Taxol or EpD increased embryo development competence, which was associated with increased mitochondrial functional activity. Consistently, delivery ratios were significantly higher after transplantation with MTS-treated embryos than after transplantation with untreated embryos. These findings suggest that MTS could be used to supplement in vitro culture media to promote the recovery of poor-quality embryos.