Relationship between Different Types of Polocyte with the Perivitelline Space and Embryonic Developmental Potential after Short-Term Insemination

Abstract

Objective: To analyze the relationship between different types of polocyte with the perivitelline space and embryonic developmental potential after short-term insemination. Methods: Early cumulus cells removal around the oocyte after short-term insemination, and the number and morphology of polocytes in the perivitelline space were observed under microscope. Then the oocytes, according to the polocyte situation, were divided into 4 groups: 2 polar body (PB), 1 PB, crushed PB (C-PB) and multiple PB (M-PB). The fertilization rate, 2 pronucleus (PN) rate, ≥3 PN rate, cleavage rate, optimal embryo rate, blastocyst formation rate, and high quality blastocyst formation rate among the 4 groups were compared. Results: The fertilization rate and 2 PN rate of the 2 PB group were significantly higher than that of the 1 PB group and the C-PB group (p < 0.01). The ≥3 PN rate of the M-PB group was significantly higher than that of the other groups (p < 0.01). There was no significant difference in cleavage rate and high quality blastocyst formation rate among the four groups (p > 0.05), but the rate of optimal embryo, and blastocyst formation rate in the 2 PB group were higher than in the 1 PB group (p < 0.01). Conclusions: The embryonic developmental potential of the oocytes with 2 PB after 4–6 h insemination were superior. It is helpful to predict embryonic development through the observation of different types of polocyte in the perivitelline space after short-time insemination.