E. V. Kornienko, A. B. Romanova, G. P. Malenko
Center for Experimental Embryology and Reproductive Biotechnology, ul. Kostyakova, 12, str. 4, Moskva, 127422, Russian Federation
Abstract. Cumulus cells surrounding a bovine oocyte are involved in its development and maturation both in vivo and in vitro, as well as in the interaction of the oocyte with spermatozoa. Removal of cumulus cells prior to in vitro fertilization typically decreases the penetration of bovine oocytes by spermatozoa. Previous studies have shown an overall high level of fertilization (83.9–84.4%) and a high level of polyspermia (29.1–39.4%) in denudated oocytes. This research was aimed at investigating the effect of the presence or absence of an intact oocyte-cumulus complex on the efficiency of fertilization of bovine oocytes matured in vitro. The cryopreserved sperm from two bulls was used as experimental material. The sperm was found to be statistically significantly different in terms of motility and survival. Regardless of the sperm used, denudated oocytes demonstrated a statistically significant increase in the polyspermia indicator (up to 29.36–32.32%) compared to intact oocyte-cumulus complexes (9.90–12.89%). Along with that, the overall penetration and normal fertilization rates in denudated oocytes remained at the same level. Therefore, the presence of intact cumulus and hyaluronic matrix cells is considered to be a factor in regulating the level of polyspermia during fertilization of bovine oocytes matured in vitro. The development of embryos up to the blastocyst stage in vitro was primarily affected by the qualitative characteristics of cryopreserved sperm rather than the presence or absence of an intact oocyte-cumulus complex during fertilization. When using bull semen with lower characteristics of sperm motility and survival, the blastocyst yield was significantly lower on the 7th day of development (4.06–4.68%) compared to that with higher characteristics (17.13–19.26%). This trend continued until the completion of cultivation on the 10th day.
Keywords: cumulus cells; cattle; oocytes; in vitro fertilization.
Author Details: E. V. Kornienko, research fellow (e-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.); A. B. Romanova, junior research fellow (e-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.); G. P. Malenko, D. Sc. (Biol.), head of division (e-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.).
For citation: Kornienko E. V., Romanova A. B., Malenko G. P. Fertilization of Bovine Oocytes with Intact Cumulus and of Denuded Сells. Dostizheniya nauki i tekhniki APK. 2019. Vol. 33. No. 9. Pp. 48–53 (in Russ.). DOI: 10.24411/0235-2451-2019-10910.