Clinical Application of Artificial Oocyte Activation Technique (AOA) in Assisted Reproduction Technology

The ICSI procedure improves fertilization rates in cases of male factor infertility. However, fertilization failure still occurs in 1-5% in ICSI cycles. The main cause of failed fertilization is failure to complete oocyte activation. Oocyte activation involves a multitude of molecular changes. The investigators use a variety of mechanical, electrical, and chemical methods to trigger the calcium oscillations necessary to activate oocytes. During mechanical activation of oocytes, oolemmas are pierced using a microneedle to trigger a calcium influx. Another method for mechanical oocyte activation is the direct microinjection of calcium into the oocyte to increase intracellular calcium. It has been described with the use of calcium ionophore A23187, which can mimic the natural pattern of calcium rise. Mechanical and chemical activation are the most commonly used methods for artificial oocyte activation, can mimic calcium oscillations resulting in successful fertilization. AOA, a highly specialized fertilization technique that can be added to conventional ICSI to overcome fertilization failure in patients that had failed fertilization or poor quality embryos history.

When the number of retrieved oocytes was >10, sibling oocytes were divided into 3 groups to perform the standard ICSI procedure (control group), chemical AOA (A1 experiment group) or mechanical AOA (A2 experiment group). When the number of retrieved oocytes was 6-10, sibling oocytes were randomized 1:1 to perform the chemical AOA (A1 experiment group) or mechanical AOA (A2 experiment group). The number of retrieved oocytes was 1-5, all oocytes were perform the chemical AOA. Control group, a single spermatozoon was injected into the ooplasm, standard ICSI procedure. A1 experiment group, were treated by injecting CaCl2 concurrently with ICSI followed by sequential exposure of calcium ionophore A23187 activation solution for two times of post-ICSI AOA. A2 experiment group, mechanical stimulation was done before standard ICSI procedure, then the oocytes were transferred into the calcium ionophore A23187 activation solution for two times of post-ICSI AOA. The investigators want to establish the effective and safe of different AOA methods, to improve the fertilization outcome and embryo quality, and finally obtain healthy offspring.