Jan Tesařík

ABSTRACT: Sperm DNA fragmentation is known to compromise male fertility. Previous findings have suggested the implication of oxidative stress in the etiology of this pathological condition. The present study was conducted to find out if the pathologically increased incidence of DNA fragmentation in ejaculated spermatozoa can be reduced by oral treatment with two antioxidants, vitamins C and E. Sixty‐four men with unexplained infertility and an elevated (≥15%) percentage of DNA‐fragmented spermatozoa in the ejaculate were randomized between an antioxidant treatment (1 g vitamin C and 1 g vitamin E daily for 2 months) group and a placebo group. Sperm DNA fragmentation was evaluated by terminal deoxyribonucleotidyl transferase‐mediated dUTP nick‐end labeling assay before and after treatment. No differences in basic sperm parameters were found between the antioxidant treatment and the placebo group before or after treatment. However, the percentage of DNA‐fragmented spermatozoa was markedly reduced ( P < .001) in the antioxidant treatment group after the treatment (9.1 ± 7.2) as compared with the pretreatment values (22.1 ± 7.7). No difference in the pretreatment and posttreatment incidence of sperm DNA fragmentation was observed in the placebo group. These data show that sperm DNA damage can be efficiently treated with oral antioxidants administered during a relatively short time period.

BACKGROUND: It is known that repeated failure of assisted reproduction treatment (ART) can be due to a paternal effect. This study was undertaken to analyse the possible relationship between ART failure and sperm DNA fragmentation. METHODS: Zygote morphology and the percentage of spermatozoa with fragmented DNA (assessed by TUNEL) were compared in two groups using donor oocytes for ICSI attempts. The experimental group consisted of 18 infertile couples who had each undergone three previous failed ART attempts. The control group included 18 randomly selected infertile couples undergoing their first ICSI attempt. Both groups used sibling oocytes from the same donors. RESULTS: In 10 couples of the experimental group, the adverse paternal effect was evident as early as the zygote stage. This early paternal effect was not associated with sperm DNA fragmentation. In eight couples of the experimental group, the adverse paternal effect did not produce any perceptible deterioration of zygote morphology. However, this late paternal effect was associated with an increased percentage of spermatozoa with fragmented DNA. CONCLUSIONS: Early paternal effect can compromise ART outcomes in the absence of increased sperm DNA fragmentation. Evaluation of sperm DNA integrity is useful to detect late paternal effect, which is not associated with morphological abnormalities at the zygote and early cleavage stages.

This retrospective study was undertaken to determine whether further developmental progression of two-pronucleated (2PN) zygotes can be predicted by a single, non-invasive examination of pronuclei, with the use of criteria based on the number and distribution of nucleolar precursor bodies in each pronucleus. The normal range of pronuclear variability was defined by analysis of zygotes giving rise to embryos transferred in 100%-implantation cycles (pattern 0). Morphological patterns differing from pattern 0 were classified as patterns 1-5. The frequency of developmental arrest of pattern 0 zygotes was only 8.5% as compared with 31.6, 21.9, 30.0, 20.5 and 24. 1% for patterns 1-5 respectively. Relationships of pronuclear patterns with blastomere multinucleation and cleaving embryo morphology were also noted. Clinical pregnancy was achieved in 22 of 44 (50%) treatment cycles in which at least one pattern 0 embryo was transferred, but only in two of 23 (9%) cycles in which only pattern 1-5 embryos were transferred. These data present new evaluation criteria which can be used to predict the developmental fate of human embryos as early as the pronuclear stage, without requiring repeated observations or an exact timing of pronuclear zygote inspection. Further prospective study is needed for clinical validation of these criteria.

BACKGROUND: Sperm DNA damage (fragmentation) is a recently discovered cause of male infertility for which no efficient treatment has yet been found. Previous findings have suggested that clinically relevant sperm DNA damage may occur at the post-testicular level. This study was undertaken to assess the clinical usefulness of ICSI with testicular spermatozoa in this indication. METHODS: The percentage of spermatozoa with fragmented DNA, assessed by terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labelling assay, and ICSI outcomes were compared in two sequential attempts performed, respectively, with ejaculated and testicular spermatozoa in 18 men with increased sperm DNA fragmentation. RESULTS: The incidence of DNA fragmentation was markedly lower in testicular spermatozoa as compared with ejaculated spermatozoa. No differences in fertilization and cleavage rates and in embryo morphological grade were found between the ICSI attempts performed with ejaculated and with testicular spermatozoa. However, eight ongoing clinical pregnancies (four singleton and four twin) were achieved by ICSI with testicular spermatozoa (44.4% pregnancy rate; 20.7% implantation rate), whereas ICSI with ejaculated spermatozoa led to only one pregnancy which was spontaneously aborted. CONCLUSIONS: These data show that ICSI with testicular spermatozoa provides the first efficient assisted reproduction treatment option for men with high levels of sperm DNA damage.

I. Introduction II. Nongenomic Actions of Estrogens A. Granulosa cells B. Endometrial cells C. Oocytes D. Spermatozoa III. Nongenomic Actions of P A. Granulosa cells B. Oocytes C. Spermatozoa IV. Nongenomic Actions of Androgens A. Sertoli cells B. Oocytes V. Signal Transduction Pathways Involved in Nongenomic Steroid Effects A. Ca2+ signal generation and amplification B. Ca2+ signal transduction C. The PTK system D. The GABAA-like receptor/Cl− channel VI. Cross-Talk Between the Nongenomic and Genomic Responses of Cells to Steroids VII. Conclusions