Successful pregnancy after SrCl₂oocyte activation in couples with repeated low fertilization rates following calcium ionophore treatment

Abstract

This report describes a successful pregnancy and delivery following oocyte activation with strontium chloride (SrCl2) in couples with repeated complete fertilization failure or low fertilization rates even after calcium ionophore treatment. Eight infertile couples who showed complete fertilization failure or low fertilization rates after conventional intracytoplasmic sperm injection (ICSI) and calcium ionophore treatment. When the results of fertilization were not satisfactory in the cycles, the oocytes were artificially activated by SrCl2 for the next attempts. Oocyte activation with SrCl2 significantly increased the fertilization rates, when compared with conventional ICSI or calcium ionophore treatment (61.7% vs. 20.0% or 25.3%, respectively). There was significant increase in the proportions of good-quality cleaved embryos (50.0% vs. 0% or 12.5%, respectively). The rate of surplus embryos that developed to blastocyst stage increased in SrCl2-treated oocytes, when compared with that in ICSI with or without calcium ionophore treatment (25.7% vs. 0% or 9.1%, respectively). Five successful pregnancies were attained after oocyte activation with SrCl2, of which eight healthy children were born. Physical and mental development of the children were normal from birth to 60 months. These results suggest that SrCl2 in treatment should be considered as an effective method for artificial oocyte activation (AOA) to improve fertilization rates and embryo quality in cases with complete fertilization failure or low fertilization rates after calcium ionophore treatment.

Single Ca2+ transients vs oscillatory Ca2+ signaling for assisted oocyte activation: limitations and benefits

“…In contrast, the efficiency of Sr 2+ in activating human oocytes is still debatable (Yanagida et al 2006, Kim et al 2015. Several authors described the efficiency of Sr 2+ in 'rescuing' human oocytes that failed to fertilize after ICSI (Kyono et al 2008, Kim et al 2014. On the contrary, other authors did not find that Sr 2+ stimulated Ca 2+ oscillations even after several hours of measurements (Rogers et al 2004, Lu 2015.…”

Strontium fails to induce Ca2+ release and activation in human oocytes despite the presence of functional TRPV3 channels

“…To date, Sr 2+ has been applied as an AOA method to overcome FF or low fertilization rates (Kyono et al , 2008; Kim et al , 2012, 2014) in several IVF centers. However, the efficiency and the exact mechanism of Sr 2+ as an activation agent in human oocytes remains largely unknown.…”

“…Thereafter, the technology of assisted oocyte activation (AOA) is frequently applied during ICSI, with the principle of inducing a Ca 2+ increase within the FF oocytes. Thus far, a number of physical, mechanical and chemical AOA methods have been evaluated, with successful oocyte activation and development to term after applying electrical pulses (Egashira et al , 2009), modified ICSI procedures (Tesarik et al , 2002), Ca 2+ ionophores (Heindryckx et al , 2008; Ebner et al , 2012; Vanden Meerschaut et al , 2014) and strontium chloride (SrCl 2 ) (Kim et al , 2012, 2014).…”

“…Despite several studies reporting successful pregnancies obtained following AOA treatment with Sr 2+ (Yanagida et al , 2006; Kyono et al , 2008; Kim et al , 2012, 2014), the efficiency of Sr 2+ as an activating agent for human oocytes is still under debate. In contrast to mice and rats oocytes studies, in which repetitive Ca 2+ transients are observed when Sr 2+ is used (Whittingham and Siracusa, 1978; Roh et al , 2003), there is a lack of evidence supporting the same for human oocytes (Versieren et al , 2010).…”

Procaine Induces Cytokinesis in Horse Oocytes via a pH-Dependent Mechanism1

“…Various methods have been employed to induce artificial calcium oscillations in mammalian oocytes in vitro and thereby provoke oocyte activation and embryo development. Electrical pulses [18], calcium ionophore [19], and strontium [20] are typically used as parthenogenetic agents, and it has been demonstrated that electrical pulses and calcium ionophore generate a single calcium elevation, whereas multiple calcium oscillations are induced by normal fertilization or strontium [20]. Moreover, there is some evidence that procaine is able to disregulate cytoplasmic calcium rise(s) in female gametes.…”