Document Type : Original Article
EMBRYOLOGY DEPARTMENT, ROYAN INSTITUTE, TEHRAN, IRAN
Introduction: Pronuclear size, morphology and orientation are known to affect embryo quality and implantation. The present study was aimed at evaluation of the possible relationship between protamine deficiency with pronuclear morphology and also cleavage and embryo quality.
Material and Methods: Semen sample of 160 candidate ICSI and IVF couples were analyzed for sperm concentration, and motility. A portion of semen was used for Papanicolaou and CMA3 staining for assessment of sperm morphology (WHO criteria) and protamine deficiency, respectively. Around 18-20 hours after sperm insemination or ICSI ‚ oocytes were scored for presence and orientation of pronuclei ‚ nuclear precursor bodies' distribution and also the axis of second polar body and were therefore categorized into & groups accordingly. Embryos were evaluated in the third day after fertilization for percentage of cleavage and embryo quality. The relationship between percentages of CMA3 positive sperms and pronuclei morphology ‚ cleavage coefficient and embryo quality were determined.
Results: Significant correlation was observed between semen parameters, percentage of fertilization and percentage of CMA3 positivity (p<0.01). Assessment of zygote morphology revealed a significant correlation between unequal pronuclei and abnormal sperm morphology (p<0.01). However no significant correlation was observed between CMA3 positivity and pronuclei morphology, cleavage and embryo quality score (p>0.05). The only significant correlation observed during zygote assessment was between nucleolar precursor body polarity ‚ distribution and percentage of cleavage on day 3. (r=0.237 p<0.001)
Conclusion: The results revealed that protamine deficient sperms have lower fertilization potency. However‚ protamine deficiency does not effect embryo development and cleavage rate post ICSI until day 3 .However pronuclei morphology is considered valuable for selection and transfer of embryo but assessment of cleavage could be used as a complementary criteria.