Decrease of spermatozoa with an unbalanced chromosome content after cell sorting in men carrying a structural chromosomal abnormality.

BACKGROUND: We showed that in men with a constitutional chromosomal abnormality, DNA fragmentation was significantly higher in chromosomally unbalanced spermatozoa than in spermatozoa with a normal or balanced chromosomal content. These results could be explained by a phenomenon already described in infertile men: abortive apoptosis. OBJECTIVES: To determine whether magnetic-activated cell separation could select spermatozoa with lower levels of DNA fragmentation and unbalanced chromosome content in men carrying a structural chromosomal abnormality. MATERIALS AND METHODS: The spermatozoa of ten males with a chromosomal rearrangement were separated into two populations using magnetic-activated cell separation (annexin V (-) and annexin V (+) fractions), in order to study meiotic segregation by fluorescence in situ hybridization, the percentage of spermatozoa with an externalization of phosphatidylserine by annexin V staining and DNA fragmentation by TdT-mediated dUTP nick-end labeling on the whole ejaculate and on selected spermatozoa in the same patient. RESULTS: For all patients, the percentage of spermatozoa with externalization of phosphatidylserine decreased in the annexin V (-) fraction and increased in the annexin V (+) fraction as compared to the frozen-thawed semen sample. The rates of DNA fragmentation were statistically much lower in the annexin V (-) fraction when compared to the rate before magnetic-activated cell separation for all but one patient. Conversely, we observed a statistically significantly higher rate of DNA fragmentation in the annexin V (+) fraction for six patients. After magnetic-activated cell separation, there was a significant increase of normal/balanced spermatozoa in the fraction of annexin V (-) for all patients. Conversely, we observed a significant decrease in the fraction of annexin V (+) for seven patients. DISCUSSION AND CONCLUSIONS: Magnetic-activated cell separation is a promising tool for increasing the selection of healthy spermatozoa, with a decrease in the number of spermatozoa with externalization of phosphatidylserine, DNA fragmentation, and chromosome unbalance, for use in assisted reproductive technologies such as intracytoplasmic sperm injection for males with a chromosomal structural abnormality.

Apoptotic sperm biomarkers and the correlation between conventional sperm parameters and clinical characteristics.

The principal aim of this retrospective study was to examine the relationship between sperm apoptotic biomarkers and the patient's biclinical characteristics, the conventional sperm parameters and the results of assisted reproductive technology. Sperm analysis, activated caspases, annexin V staining for phosphatidylserine (PS) externalisation and labelling assay for DNA fragmentation were assessed in 122 males of infertile couples. Fifty-seven couples were allocated to the natural conception group, and 65 couples underwent IVF or ICSI. Semen of IVF/ICSI patients showed a higher proportion of apoptotic spermatozoa in their spermatozoa when compared with a natural conception group (p < .05). Sperm apoptotic biomarkers correlated with age, FSH, and conventional sperm parameters. DNA fragmentation correlated positively with the percentage of semen having externalised PS (r = .78, p = 0) and activated caspases (r = .71, p = 0). Patients without clinical pregnancy had higher frequency of DNA fragmentation, externalised PS and activated caspases compared to patients with clinical pregnancy (p < .001). The best specificity and greater sensitivity were obtained with the test of the DNA fragmentation compared to the other biomarkers. Among the apoptotic biomarkers, only DNA fragmentation was found to predict natural or assisted pregnancy better than conventional sperm parameters.

Sperm RNA preparation for transcriptomic analysis: Review of the techniques and personal experience.

In the last 10 years, several approaches, including microarrays, have been applied to investigate sperm transcript levels. However, success using microarray profiling is highly dependent of the quality of the RNA obtained. Therefore, the development of methods that deliver highly purified and intact RNA is of utmost importance. The three steps used to achieve this goal, purification of spermatozoa, RNA extraction and evaluation of RNA quality, are reviewed. Following that review and preliminary experiments, we processed sperm samples from seven normozoospermic men with a combination of gradient centrifugation and somatic cell lysis. RNA was extracted using the NucleoSpin RNA XS kit (Macherey-Nagel) and its purity checked using the BioAnalyzer. Hybridisation was done on Agilent SurePrint G3 Human GE 8 × 60K V2 microarrays. We identified 900 transcripts among the 1000 high abundance sperm transcripts reported in the literature. These genes are known to be involved in several biological processes, notably spermatogenesis, transcription regulation, cell growth and differentiation, sperm motility and capacitation, fertilisation, and embryogenesis. Therefore, our methodology is highly suitable for sperm transcriptomic analyses and can be used, notably, to compare mRNA profiles between fertile and infertile males.