Use of Cyclodextrins to Increase Cytoplasmic Cholesterol in Rabbit Embryos and Their Impact on Live Kits Derived from Vitrified Embryos

BACKGROUND: Low cryotolerance in oocytes and embryos is frequently associated with lipid accumulation in the cytoplasm. OBJECTIVE: This study aimed to evaluate the effect of cyclodextrin used as a cholesterol loader to change cytoplasmic cholesterol content of embryos and raise their tolerance to cryopreservation. METHODS: In the first experiment compact morulae-early blastocysts were exposed to CLC (0.11 mM and 0.23 mM cholesterol) for 1 hour. In the second experiment, embryos were exposed to CLC (0.11 mM and 0.23 mM cholesterol) and then vitrified. RESULT: Using both concentrations, cytoplasmic cholesterol content was increased. Vitrified groups demonstrated a lower capacity for embryonic development (in vitro and in vivo) compared to the control groups. Nevertheless, live young were obtained in all groups. CONCLUSIONS: In conclusion, we have demonstrated the feasibility of using cyclodextrin as a carrier for cholesterol into rabbit embryo cytoplasm, although further studies are required to clarify the usefulness of CLC use in embryo cryopreservation.