Obesity can adversely affect human health, including fertility. While obesity can disturb the hormonal profile of the female organism and is associated with fertility loss, little is known about what effect male obesity has on fertility. The present study analysed sperm samples of 153 donors. The men were selected from couples attending an infertility clinic, who had tried for 12 months or more to achieve pregnancy without success. The age of the men under investigation was recorded, and their body mass index (BMI) was calculated. All semen samples were assessed for volume, concentration, motility and morphology. Sperm chromatin integrity was measured by sperm chromatin structure assay. Quality of sperm chromatin condensation was assessed by toluidine blue, aniline blue and chromomycin A3 staining. We can conclude that the impact of elevated BMI on the parameters investigated (basic semen parameters, chromatin integrity and chromatin condensation) was not proven in this study. On the other hand, ejaculate quality appeared to be affected by ageing. The impact was reflected by chromatin integrity, which is a factor that can substantially affect fertility in men, rather than by basic sperm parameters.

Abnormal semen parameters can serve as indicators of an additional risk of forming spermatozoa with defective chromatin and aneuploidy in translocation carriers.

A considerable proportion of male factor infertility cases are associated with inflammatory processes. The most common sexually transmissible agents causing sexually transmitted diseases in industrial countries are Chlamydia trachomatis, genital Ureaplasma and Mycoplasma spp. This study was undertaken to investigate whether these bacterial contaminants in semen affect sperm quality parameters and particularly DNA integrity (detected by sperm chromatin structure assay) in males from infertile couples (n = 293). The results showed that semen contaminations with the investigated bacterial species were not associated with sperm DNA fragmentation. However, contaminations with Mycoplasma spp. and C. trachomatis were associated with decreased sperm concentrations. Total sperm numbers in contaminated semen samples tended to be decreased, but not significantly. Mycoplasma had the highest adverse effect on sperm quality (concentration, motility, morphology and DNA condensation). Antibiotic therapy of the selected 47 men was successful in 55%, but semen quality parameters did not improve at least up to 3 months after the therapy. The presence of pathogenic bacteria in semen is primarily associated with low sperm production. Our data showed that Mycoplasma spp. contamination of semen had the highest adverse effect on sperm quality. Sperm chromatin integrity assessed by the presence of DNA breaks was not disturbed.

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Sperm chromatin status in fresh dog semen and the effect of long-term storage of chilled and frozen dog semen on sperm chromatin integrity was assessed by the sperm chromatin structure assay (SCSA). In the first experiment, the chromatin integrity of fresh semen from 60 dogs with different historiy of fertility was compared with other sperm parameters (total sperm count, sperm motility, viability, acrosomal integrity and sperm morphology). Except for 15 dogs that had never mated before, all were used in breeding as semen donors. Thirty-three of them were successful breeding males while in 12 repeated fertility problems were noted. Ejaculates were assigned to groups with good and poor quality, based on determined sperm motility and percentage of morphologically normal sperm. In the second experiment, chromatin status was measured in fresh and chilled spermatozoa (on day 0, 2, 4, 6, 8 and 10 of storage). Finally, in the third experiment, the chromatin status was measured in fresh and cryopreserved spermatozoa. Evaluating fresh dog semen, we observed that DNA fragmentation index (DFI) and percentage of cells with high DNA stainability (HDS) negatively correlated with total sperm count, percentage of total and progressively motile spermatozoa, sperm viability and percentage of morphologically normal spermatozoa, even with rather low correlation indices. Lower chromatin integrity was found in the group of dog ejaculates showing poor quality in comparison with the group of good quality ejaculates. All dogs with repeated fertility problems were classed in the group showing poor quality, and even though their DFI was significantly higher than the DFI of successful breeding males, the highest DFI we obtained was only just below 9%. We can assume that the chromatin damage level in any of the evaluated dogs was not high enough to have a significant effect on their fertility. Concerning the potential cause of reduced male fertility, the assessment of chromatin integrity in fresh dog ejaculates failed to add any additional information to the results obtained by other techniques of semen analysis. Thus, the current study indicates that neither 10-day preservation of canine sperm chilled in commercial extenders nor long-term cryopreservation in extenders recommended for canine sperm preservation produce adverse effects on sperm chromatin integrity.