DNA Fragmentation, Mitochondrial Dysfunction and Chromosomal Aneuploidy in the Spermatozoa of Oligoasthenoteratozoospermic Males

Abstract

Purpose : This study determined the incidence of sperm nuclear DNA fragmentation, mitochondrial dysfunction, and chromosomal aneuploidy. The results were correlated with the semen analysis parameters and fertilization rates. Methods : Semen samples from 10 men showing oligoasthenoteratozoospermia (OAT) and undergoing ICSI treatment were analyzed. Another semen samples from 10 men showing normozoospermia and undergoing IVF treatment were analyzed for comparison. The samples were prepared using a two-step discontinuous Percoll gradient (80%-50%) and analyzed using a Hamilton-Thorne Integrated Visual Optical System (IVOS) Sperm Analyzer. DNA fragmentation was detected with a terminal deoxynucleotidyl transferase-mediated dUTP nick end label (TUNEL) assay. Functional integrity of mitochondria was detected using an Apoalert TM Mitochondrial Membrane Sensor Kit. Chromosomal aneuploidy was assayed by fluorescence in situ hybridization. Results : Higher sperm DNA fragmentation rate (18.8% vs. 2.8%), mitochondrial dysfunction rate (24.9% vs. 5.7%), and chromosomal aneuploidy rate (0.12% vs. 0.06%) were found in the oligoasthenoteratozoospermic patients in comparison with the normozoospermic patients. Conclusions : The result indicates that spermatozoa from oligoasthenoteratozoospermic patients contain greater DNA fragmentation, mitochondrial dysfunction, and chromosomal aneuploidy. Because extremely poor semen samples are the indication for ICSI treatment, the result indicates the importance of selecting good quality sperm for oocyte injection.

Cryopreservation triggers DNA fragmentation and ultrastructural damage in spermatozoa of oligoasthenoteratozoospermic men

“…Sperm cryopreservation is wide-ranging clinical application but present procedures are not perfect, and especially semen samples from OAT patients there is an increased vulnerability to cryoinjury [1]. It is also important to demonstrate the ratio of functional sperms after thawing in OAT patients, as it has been reported that sperm from OAT patients have more DNA damage, mitochondrial dysfunction and chromosomal aneuploidy than normospermic men [5]. Extracellular and intracellular ice crystal generation, osmotic shock and cellular dehydration have been reported after freezing and thawing of human sperms [9].…”

“…The most significant alterations concerning apoptosis are phosphatidylserine production, DNA fragmentation and the creation of apoptotic structures [3]. Decreased sperm quality, increased DNA fragmentation and mitochondrial dysfunction have been reported in OAT patients [5]. It was also shown that cryopreservationthawing techniques reduced motility, viability and fertilizing ability of sperms in teratospermic patients more than in normospermic men [6].…”

Sperm DNA Fragmentation is Significantly Increased in Those Men with Morphologically Abnormal Spermatozoa

“…In assisted reproduction programs, several studies show that high levels of sperm DNA fragmentation are related to lower pregnancies rates either natural or using IUI, IVF or ICSI procedures [54][55][56][57] and higher aneuploidies rates in embryos [52,58,59]. Greco et al [60] reported 29 ICSI cycles in which the percentage of DNA-fragmented spermatozoa, detected by TUNEL assay, was >15%; only two pregnancies and no births were obtained.…”

The Effect of the Sperm Source on the Outcome of Intracytoplasmic Sperm Injection-Embryo Transfer Cycles in Normal Responder Women

“…Reduced semen quality is the main cause of male factor (2-4) and oligoasthenoteratozoospermia (OAT) is the most common diagnosis of abnormal semen quality (2). Several studies have shown that both testicular spermatozoa and poor semen quality are associated with a higher rate of sperm chromosome aneuploidy, improper meiotic recombination (5,6), sperm DNA fragmentation and mitochondrial dysfunction in patients with azoospermia (OA), OAT or severe OAT (7)(8)(9)(10). Although, a recent study indicated that impaired testicular function is reversible with different treatment modalities (11), intracytoplasmic sperm injection (ICSI) using the spermatozoa of these men may result in poor cycle outcome.…”