Correlation between aneuploidy, apoptotic markers and DNA fragmentationin spermatozoa from normozoospermic patients.

Genetic and biochemical sperm integrity is essential to ensure the reproductive competence. However, spermatogenesis involves physiological changes that could endanger sperm integrity. DNA protamination and apoptosis have been studied extensively. Furthermore, elevated rates of aneuploidy and DNA injury correlate with reproductive failures. Consequently, this study applied the conventional spermiogram method in combination with molecular tests to assess genetic integrity in ejaculate from normozoospermic patients with implantation failure by retrospectively analysing aneuploidy (chromosomes 18, X, Y), DNA fragmentation, externalization of phosphatidylserine and mitochondrial membrane potential status before and after magnetic activated cell sorting (MACS). Aneuploid, apoptotic and DNA-injured spermatozoa decreased significantly after MACS. A positive correlation was detected between reduction of aneuploidy and decreased DNA damage, but no correlation was determined with apoptotic markers. The interactions between apoptotic markers, DNA integrity and aneuploidy, and the effect of MACS on these parameters, remain unknown. In conclusion, use of MACS reduced aneuploidy, DNA fragmentation and apoptosis. A postulated mechanism relating aneuploidy and DNA injury is discussed; on the contrary, cell death markers could not be related. An 'apoptotic-like' route could explain this situation. Genetic and biochemical sperm integrity is essential to ensure reproductive success and support the earliest phases of embryo development. Paradoxically, spermatogenesis involves physiological changes that could endanger the DNA and cell integrity. Sperm-specific mechanisms have been studied extensively, and DNA packaging and programmed cell death (apoptosis) are potentially harmful. Also, elevated rates of chromosomal numerical abnormalities and breakage of sperm DNA have been correlated with reproductive failures. In this context, basic sperm examination methods have been combined with molecular tests to assess genetic integrity. On the other hand, magnetic activated cell sorting (MACS) can reduce the number of programmed-to-death spermatozoa. This system retains damaged spermatozoa, thereby improving the sample's quality. The relationships between apoptosis, DNA integrity and chromosomal abnormalities (aneuploidy) as a whole, and the effect of MACS on these parameters remain unknown. We analysed aneuploidy, DNA damage, and biochemical markers of cell death in ejaculate from normozoospermic patients with implantation failures before and after MACS. Aneuploid, apoptotic and DNA-injured spermatozoa decreased significantly after MACS. A positive correlation was detected between the reduction of aneuploidy and DNA damage; on the contrary, no correlation was determined with apoptotic markers. In conclusion, the use of MACS reduced aneuploidy, DNA breakages and apoptosis. A hypothesized mechanism relating aneuploidy and DNA injury is discussed; on the contrary, death cell markers could not be directly related. An 'apoptotic-like' route could explain this situation.