title: Prolonged exposure to hyaluronidase decreases the fertilization and development rates of fresh and cryopreserved mouse oocytes.
abstract: Hyaluronidase is generally used to remove cumulus cells from mouse oocytes before oocyte cryopreservation, intracytoplasmic sperm injection or DNA injection. In general, use of cumulus-free mouse oocytes decreases in vitro fertilizing ability compared with cumulus-surrounded oocytes. The effect of hyaluronidase exposure on the quality of mouse oocytes is not fully understood. Here, we investigated the effect of hyaluronidase exposure time on the fertilization rate of fresh and vitrified mouse oocytes and their subsequent developmental ability in vitro. We found that the fertilization rate decreased with hyaluronidase treatments. This reduction in the fertilization rate following treatment with hyaluronidase was fully reversed by removal of the zona pellucida. In addition, oocytes treated with hyaluronidase for 5 min or longer had a reduced capacity to develop to the morula and blastocyst stage. The survival, fertilization, and developmental rates of vitrified-warmed oocytes were also reduced by longer exposure to hyaluronidase. In conclusion, these results suggest that prolonged exposure to hyaluronidase decreases the quality of mouse oocytes and shorter hyaluronidase treatment times may help achieve a stable and high fertilization rate in fresh and cryopreserved oocytes.
authors.affiliation: Division of Reproductive Engineering, Center for Animal Resources and Development (CARD), Kumamoto University, Kumamoto 860-0811, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Ishizuka
authors.forename: Toru
authors.initials: T
authors.lastname: Takeo
authors.forename: Satohiro
authors.initials: S
authors.lastname: Nakao
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Yoshimoto
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Hirose
authors.forename: Yuki
authors.initials: Y
authors.lastname: Sakai
authors.forename: Yuka
authors.initials: Y
authors.lastname: Horikoshi
authors.forename: Shiori
authors.initials: S
authors.lastname: Takeuji
authors.forename: Shuuji
authors.initials: S
authors.lastname: Tsuchiyama
authors.forename: Naomi
authors.initials: N
authors.lastname: Nakagata
mesh_terms: D000818:Animals; D015925:Cryopreservation; D005260:Female; D005307:Fertilization in Vitro / Q000187:drug effects*; D006821:Hyaluronoglucosaminidase / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009865:Oocytes / Q000187:drug effects* / Q000502:physiology; D015044:Zona Pellucida / Q000502:physiology
chemical_list: D006821:Hyaluronoglucosaminidase