Differentiation Between the Effect of Protamine Deficiency and Failed Oocyte Activation on Fertilization Post ICSI

Sperm premature chromosomal condensaion (PCC) and failed oocyte activation are considered to result in failed fertilization post intracytoplasmic sperm injection (ICSI). Recent studies also suggested that sperm protamine deficiency may induce PCC. The ain of this study was to assess the effect of failed oocyte activation and protamine deficiency on failed ferilization post ICSI and to indicate whether these factors result fertilization failure, dependently or independently of each other.Materials and methods: This study consisted of 56 (first group) and 86 (second group) patients undergoing ICSI. After ICSI, the remaining processed samples were used for evaluation of protamine deficiency (Chromomycin A3 staining) and sperm morphology (Papanicolaou staining). 16-18 h post ICSI, oocytes were assessed for presence or absence of pronucleai in the both groups. In the second group te failed fertilized oocytes were chemically activated by ionomycin. Failed fertilized oocytes and chemically activated failed fertilized oocytes were fixed and stainde (Gimsa staining) for chromatin analysis.Reslts: Percentage of fertilization in the first and second groups of patients was 60.20% and 59.94%, respectively. In the second grop, percentage of fertilization rise to 83.72% following chemical activation. A significant negative correlation was observed between percentage of CMA3 positivity with ferilization rate in both groups of patients. A significant negative correlation was observed between percentage of PCC and fertilization rate in the first group while a significant posigive correlation was observed between percentage of PCC and CMA3 positivity in the second group.By subgrouping the patients into low and high CMA3 positivity in each group, the result reveal that ferilization rate, percentage of intact and PCC sperm were significantly different in the two subgroups in both groups of patients.Conclusion: the results of this study reveal that after failed oocyte activation, possibly due to sperm factors, protamine deficiency may induce failed fertilization by inducing PCC. However, mouse sperm lacking P2 protamine; have been shown to activate oocyte post ICSI, further emphasizaing these two factors may function independently of each ogher in failed fertilization.