Kinetics of human male pronuclear development in a heterologous ICSI model

Abstract

Purpose To evaluate human sperm nuclear chromatin decondensation in a heterologous ICSI system using hamster ova injected with human sperm. Materials and methods Frozen hamster oocytes were injected with Triton X-100 treated sperm and fixed at different time points post ICSI. Oocytes injected with nontreated sperm served as controls. Male pronuclear decondensation was evaluated after staining with DAPI. Results Sperm cells with partially destroyed membranes and depletion of the acrosome decondense more rapidly and to a greater extent than membrane/acrosome intact cells. Marked variability in pronuclear size was observed for any time point post ICSI, which most probably reflects the heterogeneity in the mature human sperm population. Conclusion Remodeling of male gamete nuclei in this heterologous ICSI mimics events that occur during natural fertilization in humans and therefore this approach may be used for studies of human sperm chromosomes transformations.

Diagnosis and Treatment of Male Infertility-Related Fertilization Failure

“…Hamster oocytes are known for their high survival rate even with harsh microinjection methods and for their relatively translucent cytoplasm, which permits an easy observation of different events related to fertilization [95]. Therefore, the ICSI of human sperm into hamster oocytes has been used in the past as a model to evaluate sperm head decondensation and male pronucleus formation [96]. The ICSI of human sperm with severe male-factor infertility into hamster oocytes showed a reduced percentage of sperm head decondensation [97].…”

Advances in Fertility Options of Azoospermic Men

“…If only one sperm is found, we must be reluctant to use it for anything but fertilization. As described above, because the cytoplasm of oocyte may induce heterogonous cell nucleus condensation, we may try to inject a sperm into an enucleated oocyte to observe sperm nucleus kinetics (Jones et al, 2010;Ogonuki et al, 2010). Recent studies demonstrated possibility of artificially replicating a single sperm genome, which could help men with very low sperm counts become fathers.…”

Time-lapse observation and transcriptome analysis of a case with repeated multiple pronuclei after IVF/ICSI

“…Then, the membrane vesicles become progressively incorporated into the maternal pronucleus either individually or in groups. At the same time, a continuous nuclear envelope (NE) is formed around the sperm components after remodeling [6,7]. The integrity of the NE is regulated by the activity of oocyte-derived protein kinase and phosphatase interacting with lamin A, B, and C [8].…”