EFFECTS OF A23187 AND IONOMYCIN ON OOCYTE ACTIVATION IN PATIENTS WITH PREVIOUS TOTAL FERTILIZATION FAILURE OR SEVERE OLIGO-ASTHENO-TERATOZOOSPERMIA: A 9-YEAR RETROSPECTIVE STUDY

Abstract

To assess effects of the applications of Ca2+ ionophore A23187 and Ionomycin on fertilization rate, embryonic developmental potential and clinical outcomes in patients with a history of total failed fertilization/lower fertilization rate or severe oligo-astheno-teratozoospermia. A 9-year retrospective study was conducted with clinical-based data at Reproductive Medicine Research Center of the Sixth Affiliated Hospital of Sun Yat-sen University from May 2010 to December 2019. The indications for assisted oocyte activation (AOA) in our center were: (1) patients with total failed fertilization (0%)/lower fertilization rate (fertilization rate <33.3%) in previous ICSI cycles (at least three mature oocytes on the day of oocyte retrieval); or (2) severe oligo-astheno-teratozoospermia including globozoospermia, cryopreserved micro-dissection testicular sperm extraction (MD-TESE) and cryopreserved rare human spermatozoa. The AOA procedure was performed as follows: the oocytes were exposed to either the ready-to-use A23187 solution (GM508, Cult-Active, Gynemed) or 10μM ionomycin (407952,Sigma-Aldrich) after ICSI. All patients were categorized into two groups: A23187-AOA group and Ionomycin-AOA group. And each group was divided into two subgroups according to origin (ejaculated or testicular sperm). Statistical analyses were performed by SPSS 22.0 with the chi-square test, Yates' correction, or Fisher's exact probabilities accordingly when comparing frequencies or proportions. P <0.05 were considered to be statistically significant. A total of 65 patients whose oocytes were exposed to either the A23187-(n=39) or Ionomycin-AOA (n=26) protocol were included in the final analysis. Significantly higher 2PN fertilization rate (55.0% vs. 43.3%, P<0.01), 2PN cleavage rate (97.4% vs. 90.4%, P<0.05) and blastocyst formation rate (69.1% vs. 45.2%, P<0.05) were observed in Ionomycin-AOA group compared with those in A23187-AOA group. In ejaculated spermatozoa subgroup, 2PN cleavage rate (97.1% vs. 85.8%, P<0.05) and rate of D3 transferable embryos (92.6% vs. 73.6%, P<0.01) in Ionomycin-AOA group were higher than those in A23187-AOA group; In testicular spermatozoa subgroup, the 2PN fertilization rate(55.4% vs.37.7%, P<0.05), blastocyst formation rate(93.3% vs.20.0%,P<0.01) and cumulative clinical pregnancy rate(66.7% vs.10.0%, P<0.05) in Ionomycin-AOA group were higher than those in A23187-AOA group. A total of 20 healthy neonates were delivered in 65 patients and 9 pregnancies were ongoing. None of congenital anomalies (birth defects) was found in fetuses following AOA. Ionomycin may be superior to A23187 for improving fertilization rate and embryonic developmental potential. And compared with A23187, Ionomycin provides better clinical outcomes for patients with testicular-origin severe oligo-astheno-teratozoospermia.