Bases subcelulares de la patología espermática: claves para el entendimiento de la contribución masculina a la fertilización y desarrollo embrionario temprano.

CHEMES HECTOR E.

Mar del Plata , Argentina

Simposio; LVIIReunión Científica de la Sociedad Argentina de Investigación Clínica; 2012

Sociedad Argentina de Investigación Clínica

Bases subcelulares de la patología espermática: claves para el entendimiento de la contribución masculina a la fertilización y desarrollo embrionario temprano. Cellular and molecular mechanisms underlying sperm pathology: clues for the understanding of the male contribution to fertilization and early embryonic development. Héctor E. Chemes Fertilization in mammals is the result of a series of well defined events such as sperm capacitation and the acrosome reaction, sperm-zona binding, fusion of gamete membranes and oocyte penetration and activation. This intricate process has occurred across millennia in the secluded environment of the female reproductive tract and the mode of selection of the fertilizing spermatozoon has evaded the inquiring eye of many generations of scientists. Since the introduction of modern Assisted Reproductive Technologies (ART) it has been possible to follow subcellular events at and after fertilization, and it became evident that abnormal spermatozoa could successfully fertilize oocytes. In these extreme conditions, post-fertilization events, early embryonic development and implantation may be compromised, which indicates that the contribution of spermatozoa extends well beyond sperm penetration. Even though microscopic identification of normal spermatozoa is a standardized procedure, insight into the subcellular nature of sperm abnormalities and the mechanisms that lead to aberrant sperm differentiation has only recently began to unfold. The spermatozoon is the result of a complex development in which spermatid organelles give rise to various structural components with characteristic functions. Similar to other differentiated cells the spermatozoon has a specific pathology that is most clearly identified by the use of ultrastructural evaluation coupled with immunocytochemistry and molecular techniques. In this presentation we will review the differential roles played by individual sperm components in normal fertilization and early embryo development. Phenotypes of genetic or acquired origin involving sperm heads, flagella, and the neck region will be presented describing their structural, cytochemical, molecular and genetic characteristics. When available, animal models will be used to highlight physiopathology. Flagellar anomalies bear a good fertility prognosis, but those affecting the acrosome, sperm chromatin and the neck region entail an increasing chance of failure, which underlines the differential roles played by specific sperm components in fertilization, implantation and early embryonic development.