The relationship between human sperm structural chromosomal anomalies and sperm cellular maturation

ABSTRACTBiochemical markers of sperm maturity and function are important researchsubjects in the last years. It has been concluded that only mature sperm are able tobind to Hyaluronic acid (HA). Thus, HA sperm selection provides a new, safe, andefficient solution for selection of mature, chromosomally normal sperm for clinicalapplication in assisted reproduction. It is well known that spermatogenetic defectsmay also cause structural chromosomal aberrations, or karyotypic changes in humanspermatozoa. Indeed, in men with diminished sperm concentrations and loweredfertility, the frequencies of sperm with abnormal karyotypes are increased and thesemen are candidates for Intra Cytoplasmic Sperm Injection (ICSI). Therefore, in thepresent study it has been purposed to investigate the potential relationship betweenchromatin maturity, cellular immaturity and chromosomal structure in human spermby using different techniques based on their ability to bind HA.In the present study, after preparation of samples originated in oligospermicand normospermic men, the sperm chromatin maturity and cellular maturity wereassessed by aniline blue staining and CK-B immunofluoresance stainingrespectively, in HA-bound and unbound sperm fractions. Three dimensionalstructural changes were examined by Transmission Electron Microscopy (TEM), andultrastructural properties and membrane integrity were compared in semen, HA-bound or -unbound sperm fractions. On the other hand, hamster or mouse oocyteswere used to see human sperm chromosomes at metaphase stage.It has been shown that there was a strong relationship between spermmaturity and the ability of HA-binding after application of different techniques. HA-bound sperm showed no cytoplasmic retention having mature chromatin structure.Our data supported the idea of sperm binding to HA via the plasma membranereceptors represents unequivocal evidence of completed spermiogenetic maturation.As a result, HA-binding capacity and the extent of cytoplasmic retention inindividual sperm are related to each other and also to chromatin maturity. Furtherinvestigations needs to be done on molecular level based on the recent knowledge onspermatozoal mRNA to highlight the complex mechanisms about fertilization.Key Words: Human sperm maturity, fertilization, Hyaluronic acid sperm selection,ICSI, chromosomal aberrations.