The effect of bacterial contamination of semen on sperm chromatin integrity and standard semen parameters in men from infertile couples.

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.

Male obesity and age in relationship to semen parameters and sperm chromatin integrity.

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.

Fertile bull sperm aneuploidy and chromatin integrity in relationship to fertility.

Aneuploidy is associated with spontaneous abortions, perinatal mortality, mental retardation and with embryonic and foetal mortality. Most of these abnormalities originate as a result of meiosis errors during gametogenesis. The main purpose of the study was to analyse frequency of aneuploidies of sex chromosomes and chromosome 6 by three-colour fluorescence in situ hybridization (FISH) in 47 young bulls, candidates for artificial insemination programme with cryopreserved semen and to investigate the influence of aneuploidies and disturbed sperm chromatin integrity on non-return rates, the frequencies of abortions, perinatal mortality and stillbirths. The average frequencies of spermatozoa with disomy for chromosomes X, Y, XY and 6 were 0.032, 0.005, 0.003 and 0.039% respectively. The incidence of XX66, YY66 and XY66 diploidy was 0.017, 0.006 and 0.015% respectively. Frequencies of meiotic II errors were significantly higher than meiotic I errors (p < 0.01). More X bearing spermatozoa than Y bearing spermatozoa were detected (5151 vs. 5022; p < 0.01). Sperm chromatin damage expressed by DNA fragmentation index (DFI) was 5.3 +/- 3.7 and percentage of cells with defective chromatin condensation (HDS) was 1.4 +/- 0.8. No correlation was found between sperm aneuploidy and basic sperm analysis. The relationship was found between non-return rate and total aneuploidy (r = -0.310; p = 0.036). Significant correlation was found between sex disomy, total aneuploidy (disomy of chromosomes 6, X, Y and XY spermatozoa and diploidy) and stillbirths (r = 0.390; p = 0.013; and r = 0.331; p = 0.037). Chromosome 6 disomy correlated with perinatal mortality (r = 0.317; p = 0.047). HDS correlated significantly with total aneuploidy (r = 0.449; p = 0.002). Our study indicated that aneuploidy frequencies in young fertile bull spermatozoa are relatively low. Nevertheless, there exists a variability in aneuploidy frequencies amongst bulls, which appears to be able to have an influence on the fertility of these animals.

Sperm chromatin integrity in young men with no experiences of infertility and men from idiopathic infertility couples.

Damage to the genetic component of spermatozoa seems to play the main role in a majority of cases where current approaches fail to reveal the specific cause of male infertility. In this study, we compared semen quality in men assigned to two defined groups: men from couples with unexplained infertility - idiopathic infertility (A) and young men with no experiences of infertility (B). All samples were examined by standard ejaculate analysis and sperm chromatin structure assay (SCSA). Sperm chromatin damage was significantly higher in men from group A than in those from group B. Similar results were obtained by comparison of men from group A (all men were normozoospermic) with normozoospermic men from group B. According to these results, we can suppose that chromatin disorders may be the causal factor of subfertility or infertility in some of these men. No evidence for a strong association between chromatin disorders and standard parameters of ejaculates was found. We failed to confirm a relationship between smoking and sperm quality in men from any of the investigated groups. SCSA is a method that facilitates the identification of infertile men who otherwise show normal semen variables.