FACTORS AFFECTING ACTIVATION AND FERTILIZATION OF HUMAN OOCYTES FOLLOWING INTRACYTOPLASMIC INJECTION

Intracytoplasmic sperm injection (ICSI) has dramatically altered the t reatment of severe male factor infertility, resulting in improved fert ilization and pregnancy rates, The purpose of this study was to invest igate oocyte activation and fertilization in aged human oocytes follow ing ICSI, Non-viable spermatozoa were injected into 24 h old human ooc ytes in the presence and absence of calcium and were assessed for evid ence of activation and fertilization 16-19 h after the injection proce dure, Sham injections were also carried out to assess the effect of th e injection procedure itself and the presence of calcium in the inject ion medium on oocyte activation, Non-viable spermatozoa injected in th e presence of 1.78 mM calcium were capable of normally fertilizing age d human oocytes and the resulting zygotes underwent cleavage. None of the oocytes injected with nonviable spermatozoa in the absence of calc ium were fertilized normally, although the rates of activation followi ng all treatments were similar.