Introduction: Sperm premature chromosomal condensation (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 aim of this study was to assess relation of failed oocyte activation and protamine deficiency on individuals with failed fertilization post ICSI and to indicate whether these factors result in fertilization failure, dependently or independently of each other.
Materials and M ethods: Metaphase II oocytes were obtained from 86 ICSI candidate, then oocytes were injected with processed semen samples. After oocyte insemination, the remaining of 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 pronuclei and unfertilized oocytes were chemically activated by ionomycin. Finally failed fertilized chemically activated oocytes were also fixed and stained (Gimsa staining) for chromatin analysis.
Results: In this study percentage of fertilization was 59.94, which increase to 83.72% following chemical activation. The results of this study reveal a significant correlationbetween the percentage of protamine deficiency with percentage fertilization rate, PCC, intact sperm and abnormal sperm morphology.
By sub grouping the patients into low and high CMA3, the results reveal that percentage fertilization, intact sperm and PCC sperm were significantly different in the two subgroups.
Conclusion: The results of this study reveal that after failed oocyte activation, PCC induces through protamne deficiency may be considered as the second cause of failed fertilization post ICSI. However, it remains still unclear whether protamine deficiency may be involved in the mechanism of failed oocyte activation.