Fluorescent enzyme-based biosensor for sensitive analysis of DNA damage in cryopreserved sperm.

The freeze-thaw process can induce irreversible structural and functional changes in human sperm, particularly sperm DNA damage. Selecting a more accurate and sensitive detection method for evaluating sperm DNA integrity is crucial. To accurately assess sperm DNA integrity following the freeze-thaw process and significantly improve the clinical and scientific utilization of cryopreserved sperm. In this study, we utilized a novel fluorescent biosensor, assisted by terminal deoxynucleotidyl transferase (TdT) and Endonuclease IV, to detect DNA breakpoints during sperm cryopreservation. We evaluated the biosensor's performance by comparing it with the conventional DNA fragmentation index (DFI) measured using sperm chromatin structure analysis (SCSA). The cryopreserved group exhibited a significantly higher sperm DFI compared to the fresh group. No significant difference was observed between the antioxidant group and the cryopreserved group. However, the new method revealed a significant reduction in the number of DNA breakpoints in the antioxidant group compared to the cryopreserved group. The novel biosensor demonstrated superior accuracy and effectiveness in assessing sperm DNA integrity during cryopreservation compared to the conventional SCSA method. We believe that the biosensor holds significant potential for widespread use in the field of reproductive medicine.

Evaluation of Sperm DNA Integrity by Mean Number of Sperm DNA Breaks Rather Than Sperm DNA Fragmentation Index.

BACKGROUND: Sperm DNA integrity is crucial for normal fertilization, implantation, and embryo development. Several assays are available to assess sperm DNA fragmentation but are limited by high price, complicated processes, and low accuracy. METHODS: We developed a secondary amplification detection system based on terminal deoxynucleotidyl transferase and endonuclease IV, which could efficiently measure the number of 3'-OH (equivalent to the number of breakpoints). We applied this detection system in single stranded DNA with standard concentrations to obtain the standard curve. We then broke the double stranded genomic DNA by ultrasound and enzyme digestion and used the detection system to monitor the increase of DNA breakpoints. Finally, we used this method to measure the mean number of sperm DNA breakpoints (MDB) in 80 sperm samples. RESULTS: We successfully measured the number of 3'-OH in single stranded DNA with standard concentration and obtained the standard curve. The linear range for the number of DNA breakpoints was from 0.1 nM to 15 nM. The detection method was successfully validated on λ DNA and 80 human sperm samples. The results of real clinical samples revealed that the mean number of DNA breakpoints (MDB) had a stronger relevance with the sperm motility and clinical pregnancy outcomes than the commonly used parameter of DNA fragmentation index (DFI). CONCLUSION: We have developed a straight-forward method for direct measurement of the mean number of DNA breakpoints in sperms. The method has advantages of short time-consumption, simple operation, high analytical sensitivity, and low requirement for instrumentation, which makes it conducive to clinical application. The proposed new parameter (MDB) could be a more direct, accurate and clinically significant indicator for evaluating the sperm DNA integrity.

[Seminal plasma anti-Müllerian hormone and inhibin B and serum inhibin B in predicting the outcome of routine IVF fertilization].

OBJECTIVE: To analyze the correlations of seminal plasma (sp) anti-Müllerian hormone (spAMH) and inhibin B (spINHB) and serum INHB (serINHB) with semen parameters in oligoasthenospermia patients and explore their value in predicting the outcome of routine in vitro fertilization (IVF). METHODS: We obtained the levels of spAMH, spINHB and serINHB as well as semen parameters from 88 infertile males undergoing IVF due to oligoasthenospermia or female uterine tubal factors from August 2016 to February 2017. Using the ROC curve and Pearson's correlation analysis, we examined the effects of the obtained parameters on the fertilization rate and assessed the correlation of the levels of spAMH, spINHB and serINHB with the semen parameters of the patients. RESULTS: Concerning the predictive value for the outcome of IVF, Pearson's correlation analysis showed that the area under the ROC curve (AUC) of spAMH was 0.807 (sensitivity = 84.6%, specificity = 76%, cut-off point = 3.529, P <0.001) and that of spINHB was 0.768 (sensitivity = 84.6%, specificity = 88.7%, cut-off point = 31.117, P = 0.002). The serINHB level was found positively correlated with sperm concentration (r = 0.346, P = 0.001), total sperm count (r = 0.378, P <0.001), sperm motility (r = 0.521, P <0.001), and the percentage of progressively motile sperm (r = 0.343, P = 0.001). CONCLUSIONS: The levels of spAMH and spINHB can be used as laboratory indexes to predict the fertilization rate of routine IVF and are correlated with semen parameters in oligoasthenospermia patients, while that of serINHB has a positive correlation with the semen parameters of the patients.

[Relationship between ERCC2 single nucleotide polymorphisms and male idiopathic infertility in Ningxia].

OBJECTIVE: To explore the influence of the DNA repair gene ERCC2 single nucleotide polymorphisms (SNPs) rs13181, rs1618536, and rs1799793 on male idiopathic infertility in Ningxia, China. METHODS: Using MassArray, we conducted a case-control study and genotyped three ERCC2 SNPs rs13181, rs1618536, and rs1799793 for 351 males (aged 31.0 +/- 4.2 years) with idiopathic infertility and another 327 normal fertile men (aged 33.0 +/- 5.9 years) as controls. RESULTS: The ERCC2 AnyG-anyA-anyA genotypes were significantly associated with an increased risk of idiopathic infertility (OR 0.414, 95% CI 0.176 - 0.970), while the three single ERCC2 SNPs rs13181, rs1618536, and rs1799793 showed no significant differences between the cases and controls (P > 0.05). CONCLUSION: The ERCC2 SNPs rs13181, rs1618536, and rs1799793 play a role of interaction in male idiopathic infertility in Ningxia, contributing to the risk of the disease.

DNA strand displacement and TdT-Mediated DNA extension for swift, convenient, and quantitative evaluation of sperm DNA integrity and its clinical implications.

DNA integrity is crucial for the clinical pregnancy outcome and offspring health, while detection methods currently used (comet assay, TUNNEL assay, SCSA, etc.) can only provide the ratio of positive sperms at the cellular level and are unable to quantitatively detect the breakpoints at the DNA molecular level. Herein, we developed a detection system based on terminal deoxynucleotidyl transferase and DNA strand displacement fluorescent probe, which could efficiently and conveniently measure the number of 3'-OH (equivalent to the number of breakpoints). We further investigated the use of this technique in assisted reproduction after completing the principle verification, system optimization, and research on analytical performance. The detection system was shown to have a good linear range from 0.01 nM to 4 nM, using single-stranded DNA with 3'-OH end as the calibrator. The system underwent thorough optimization for stability and accuracy. In comparison to the widely accepted index DFI detected by SCSA, the new system demonstrated reasonable correlation and better prediction efficiency. Its applicability was also proven through its use in assisted reproductive technology procedures.

Inhibitory effect of Lycium barbarum polysaccharide on sperm damage during cryopreservation.

With the development of cryopreservation technology, marked progress has been made regarding sperm cryopreservation. However, as conventional cryopreservation agents are not effective at freezing weak sperm, improved cryopreservation agents are in demand. In the present study, the addition of Lycium barbarum polysaccharides to glycerol-egg-yolk-citrate sperm cryopreservation agent was determined to improve sperm forward speed, reduce the DNA fragmentation index and improve the mitochondrial membrane potential. Furthermore, during the freezing and thawing of sperm, the improved cryopreservative increased the content of Bcl-2 while reducing the content of Bax, cytochrome C and caspase-3. These results indicated that polysaccharides added as a protective agent preserved the normal function of sperm mitochondria. Transmission electron microscopy also confirmed the protective effect of the polysaccharides on the structure of mitochondria. It was also indicated that improved cryopreservative lowered the levels of reactive oxygen species (ROS) during the freeze-thawing process. Therefore, it is hypothesized that improved cryopreservative agents may be beneficial for maintaining the structure and function of the mitochondria of weak sperm when cryopreserved, which may be facilitated via reducing the production of ROS in the freezing-thawing process, thus avoiding activation of the apoptotic pathway in sperm mitochondria and protecting mitochondrial structure and sperm function.