Objective: To investigate the influence on developmental potential of frozen-thawed rabbit oocytes with double assisted activation followed by intracytoplasmic sperm injection (ICSI).
Methods: A total of rabbit oocytes were collected and thawed after vitrification cryopreservation. Among all oocytes were cultured for 1 hour followed by ICSI. 156 Survived oocytes were divided into 5 groups randomly. I0634 single activation: 30 oocytes were added with calcium ionomycin (I0634) at 5 micromol/L for 5 minutes; SrCl(2) single activation: 26 oocytes were added with strontium chloride at 10 mmol/L for 10 minutes; I0634 double activation: 33 oocytes were activated by I0634 twice; SrCl(2) double activation: 28 oocytes were activated by strontium chloride twice.
Control group: 39 oocytes were not added with any activators. The rate of fertilization, cleavage and blastocysts formation were observed and compared between various groups.
Result: The rates of fertilization, cleavage and blastocysts formation were in group of SrCl(2) single activation were higher than those of I0634 single activation group without statistical difference (54% vs.33%, 27% vs. 17%, 8% vs. 3%, P < 0.05). However, those above rates in double activation by I0634 were higher significantly than those of single I0634 activation (82% vs. 33%, 55% vs. 17%, 15% vs. 3%, P < 0.05). The rates of fertilization (61%) was higher and the rate of cleavage (21%) and blastocysts formation (7%) were lower in group of SrCl(2) double activation in comparison with group of SrCl(2) single activation without reaching statistical difference (P < 0.05). Notably, the rates of fertilization, cleavage and blastocysts formation in I0634 double activation group were higher than those in group of SrCl(2) double activation with statistical difference (82% vs. 61%, 55% vs. 21%, 15% vs. 7%, P < 0.05).
Conclusion: It might enhance the potential of fertilization of oocytes and early embryo development treated by double activation following ICSI, however, those activated oocytes demonstrate rapid cleavage.