Developmental sperm contributions: fertilization and beyond

The predictive value of high-magnification sperm morphology examination on ICSI outcomes in the presence of oocyte dysmorphisms

“…The dish was placed on a microscope stage above a Uplan Apo × 100 oil/1.35 objective lens previously covered by a droplet of immersion oil. The sperm cells exhibiting normally shaped nuclei ([1] smooth, [2] symmetric, and [3] oval configuration) and [4] normal nuclear chromatin content (if it contained no more than one vacuole, which occupies <4 % of the nuclear area) were selected for injection [5-8, 14, 25, 47].…”

“…The activation of the embryonic genome occurs at the stage of 4-8 cells [13]. As a result, the effects of injection of sperm with nuclear abnormalities are usually not detected before the 8-cell stage, when a high expression of genes derived from the sperm is initiated [4]. Studies suggest that this result reflects a late paternal effect, which is related to blockage of embryonic development observed during / after the implantation of embryos with normal karyotype [10,43].…”

Association of progesterone receptor gene polymorphism with male infertility and clinical outcome of ICSI

“…Beyond the maternal genome, evidences are now available where the paternal genome has also been suggested to influence embryogenesis. Growing body of evidences suggest that mature sperm provide appropriate epigenetic marks that drive specific genes toward activation and contribute to the pluripotent state of the embryonic cells [19]; in addition it also provides several classes of non-coding RNAs including miRNAs, lncRNAs, novel elements and mRNAs that are likely to be essential for early development [6,36]. It is possible that defects in the paternal genome and/or abnormal RNA profiles in the spermatozoa may lead to failure of embryonic growth, pregnancy loss, and/or developmental abnormalities.…”

Infertility treatment, a matter of a lovely sperm?

“…One explanation may rely on sperm attributes since the commitment of the spermatozoon is not only to fertilize the egg but also to directly affect early embryo development and implantation. 2 Therefore, the selection of a 'good' spermatozoon becomes essential, especially for intracytoplasmic sperm injection (ICSI) into the egg. This medical procedure, called ICSI, is the most popular ART nowadays.…”

“…Oxidative stress is a well-known stimulus for DNA fragmentation, which is one of the causes of failure of fertilization, embryo development and implantation. 2 After SSA, the level of oxidative stress and DNA fragmentation is significantly reduced, while sperm motility and viability are kept constant and high. Thus, the SSA supplies an elite subpopulation composed of spermatozoa that are capacitated, with intact DNA, low oxidative stress and high levels of motility and viability.…”