Abstract:

Objective: To evaluate the effect of different standing time of mouse docking sperm in intracytoplasmic sperm injection
（ICSI）on embryo development potential. Methods: Ten groups were divided by docking sperm standing time（0, 0.5, 1, 2, 3, 4, 5, 6,
12, 24 h）. The rates of pronucleus formation, 2-cell formation, 4-cell formation, morulation and blastocysts formation were compared
between each experimental group and the control group. Results: The pronucleus formation rate（68.4% vs. 82.5%）, and the 2-cells
formation rate（83.3% vs. 96.0%）were significantly lower in the standing 6 h group than those in the control group（P<0.05）. The 4-
cells formation rate（59.8% vs. 79.8%）was significantly lower in the standing 4 h group than that in the control group（P<0.05）.
Morulation rate（47.9% vs. 67.7%）was significantly lower in the groups with standing 2 h group than that in the control group（P<
0.05）. The average blastocyst formation rate（38.9% vs. 53.5%）was significantly lower in all standing groups than that in the control
group（P<0.05）. The Blastocyst formation rate dropped significantly as the standing time extension. No blastocyst was observed when
standing time longer than 3 h. Conclusion: Delay of mouse docking sperm ICSI reduced the development potential of mouse embryo.

Key words: docking sperm, different time, embryo development potential