Effects of calcium ionophore A23187 on oocyte activation, embryo development following intracytoplasmic sperm injection technique and pregnancy rate in bovine

B. Habsah, K. Musaddin, A.J. Izuan Bahtiar, J. Ahmad and A.S. Shamsul Azlin

Abstract

The efficiency of intracytoplasmic sperm injection (ICSI) technique in cattle reproduction is limited by the necessity for additional oocyte activation step before or after the ICSI procedure. Induced activation is required for oocyte to progress beyond the pronuclear stage and subsequent embryo development. Therefore, three experiments were conducted to study the fertilisability and development of oocytes following ICSI. In experiment 1, calcium ionophore A23187 was used to activate oocytes and determine its effect on the subsequent development of oocytes following ICSI. Amongst the treatments, either pre- or post-oocyte calcium ionophore activation treatment was more effective than a combination of both treatments. In Experiment 2, the status of uncleaved zygotes with or without polar bodies was evaluated following ICSI. The majority of fertilisation and development failures in oocytes with or without polar bodies were related to either the failure of sperm head decondensation and male pronucleus formation despite activation and development of ICSI oocytes. In Experiment 3, the pregnancy rates of recipient dams following transfer of ICSI- and in vivo-derived embryos were 25% and 50% respectively. In conclusion, a 5 μM calcium ionophore A23187 treatment before or after ICSI could induce oocytes activation that resulted in pregnancy of recipient dams.

Full text (404 KB)