OBJECTIVETo investigate the sex chromosomes and the expression of insulin-like growth factor-II (IGF-II) on activated human unfertilized oocytes after intracytoplasmic sperm injection(ICSI) with calcium ionophore A23187 and puromycin.

METHODSAll 95 discarded oocyes that showed no evidence of fertilization at 16-18 h after in vitro maturation and intracytoplasmic sperm injection cycles (IVM-ICSI)/conventional ICSI were exposed to calcium ionophore A23187 (5 micromol/L) for 5 min and then were incubated with puromycin (10 microg/mL) for 4 h. After activation, the oocytes were cultured in vitro for 3-5 days. The sex chromosome analysis was performed by dual color fluorescence in situ hybridization. The expression of IGF-II on the activated embryos, normal embryos, and parthenotes was examined.

RESULTSThe combination of calcium ionophore A23187 with puromycin could activate the unfertilized oocytes 22 h after ICSI. The activated rate, cleavage rate, and quality of activated embryos of the IVM-ICSI group were similar to those of ICSI group, respectively. Sex chromosome analysis indicated that 8 male and 5 female embryos had been derived from two pronucleus and a second polar body. The expression of IGF-II on activated embryos and normal embryos was high and similar, which was much stronger than that of parthenotes.

CONCLUSIONThe combination of calcium ionophore A23187 with puromycin could effectively activate unfertilized oocytes 22 h after ICSI. Moreover, the unfertilized oocytes activated by calcium ionophore A23187 and puromycin had normal sex chromosomes and expression of IGF-II like the normal embryos. These suggest that oocyte activation may be considered as a remedial measure in the presence of total or nearly total fertilization failure in ICSI.