The Effects of Protamine Deficiency in Sperm Humanon Premature Chronosomal Condensation

Purpose: After aneuploidy, failure of oocyte activation, resulting in premature chromosomal condensation (PCC), is considered as the second cause of failed fertilization post ICSI. Oocyte quality has been shown to affect PCC formation, and since this study sought to evaluate the effect of sperm chromatin anomalies on the PCC, mice metaphase II oocytes were used. Materials and Methods: Metaphase II oocytes were obtained from mice. Simultaneously, semen samples obtained from infertile men were evaluated for protamine deficiency using chromomycin A3 (CMA3). Then the samples were divided into protamine deficient or normal. After that the collected oocytes were inseminated by direct intracytoplasmic sperm injection with sperms from the aforementioned groups. After 3h, the injected oocytes were transferred to medium containing clocimde. 19 h post insemination, the injected oocytes were assessed for the chromatin status using the Gimsa staining. Results: Percentage of intact or PCC sperms was significantly different between the oocytes injected with sperm from the two groups. The percentage of abnormal sperms was also significantly different between the two groups. A significant correlation was also observed between protamine deficiency with the percentage of PCC and sperm with intact head in the injected oocytes and also with the percentage of abnormal sperm. Conclusion: Protamine deficiency prone sperm to PCC and protamine deficient sperms or sperms with excessive histone have a higher chance of inducing PCC. With the increase in the percentage of protamine deficient sperm, the percentage of PCC in the injected oocytes increases, while the percentage of intact sperm decreases. This phenomenon may lead to lower fertilization rates post ICSI.