Aneuploidy and DNA fragmentation in morphologically abnormal sperm

Abstract

In light of the relative success of ICSI in the treatment of male infertility, much importance has been made to the selection of morphologically viable sperm. However, correlation between specific sperm morphology and chromosomal abnormalities is still relatively limited and less is known about the connection between sperm morphology and DNA integrity. Sperm obtained from isolated teratozoospermic men (n = 10) and control men (n = 9) were analysed using FISH (for chromosomes 13, 18, 21, X and Y) and TUNEL assays to determine the level of aneuploidy and DNA fragmentation. Sperm morphology was evaluated on its ability to identify the level of chromosomal abnormalities or fragmented DNA in sperm. Sperm from teratozoospermic men, compared with fertile men, had higher rates of total chromosomal abnormality (p < 0.05), total aneuploidy (p < 0.01) and chromosome 13 disomy (p < 0.01). Associations between particular types of sperm morphology and chromosomal abnormalities were observed in both control (tapered heads) and teratozoospermic (amorphous heads and tail abnormalities) samples. Levels of DNA fragmented sperm were higher in teratozoospermic men than in the control men (60.28 +/- 21.40% vs. 32.40 +/- 17.20%, p < 0.05) and positively correlated to sperm with bent necks in control samples and round heads in teratozoospermic samples (p < 0.05). Sperm of isolated teratozoospermic men have higher rates of chromosomal abnormalities and DNA fragmentation than that of the fertile controls. Specific abnormal sperm morphology can be correlated to chromosomal abnormalities and level of DNA fragmentation in sperm.

CASA derived human sperm abnormalities: correlation with chromatin packing and DNA fragmentation

“…In the present study too the DFI was significantly higher in morphological abnormal groups compared with normal group. These findings are in agreement with previous studies conducted on infertile patients by several authors [32,[39][40][41]. Abnormal head sperm morphology was also shown to have a negative correlation with sperm motility parameters [21,43,44].…”

“…Later studies by Sheikh et al also confirmed that DNA fragmentation rate was higher in sperms with abnormal morphology [32]. Further studies by Tang et al reported specific abnormal forms such as tapered and amorphous forms had higher rates of chromosomal abnormalities and DNA fragmentation [40]. Recently, Daris et al further proved that specific head abnormalities, especially amorphous heads had elevated degree of DNA fragmentation [41].…”

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

“…Similarly, Abdelrazik et al [50] analyzed sperm morphology using computer assisted morphometry, and demonstrated that spermatozoa with several abnormal forms (in particular amorphous and micro heads) containing immature chromatin and higher DNA fragmentation rate compared with other forms of head abnormalities resulting in an increase in aneuploidy incidence and mutations in the germ line [44,51]. In the present study, it was demonstrated that DNA fragmentation was significantly higher in teratozoospermic men compared with normozoospermic men, similar to the results shown by several authors [44,48,50,52,53].…”

“…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.…”

Assessment of Human Sperm Cells Morphological Parameters

“…Abnormal tails (two-tailed, bent tails, irregular tails) are associated to chromosome 13 disomy, supernumerary chromosomal abnormalities and the cytoskeletal abnormalities (including centriolar defects) [57].…”