Does conventional freezing affect sperm DNA fragmentation?

The evaluation effect of nanoliposome-loaded Mito-Tempo on sperm parameters during human sperm cryopreservation

AIM

The aim of this study is the evaluation effect of nanoliposome-loaded Mito-Tempo on sperm parameters during human sperm cryopreservation.

METHODS

Semen samples of 50 Asthenoteratozoospermia men (random) were collected. Sperm parameters were analyzed based on World Health Organization (WHO, 2010) criteria (2021) and each sample was divided into 5 groups (E1-E5). E1 (control group): the sperm was cryopreserved without nanoliposome, and Mito-Tempo. E2: sperm cryopreservation with Mito-Tempo-loaded nanoliposome (Mito-Tempo 0.1 mM) + freezing medium. E3: sperm cryopreservation with Mito-Tempo-loaded nanoliposome (Mito-Tempo 0.2 mM) + freezing medium. E4: in this group, the cryopreservation sperm with Mito-Tempo 0.3 mM + freezing medium. E5: the cryopreservation sperm with Mito-Tempo 0.2 mM + freezing medium.

RESULTS

The result of this study indicated that sperm parameters and total antioxidant capacity (TAC) significantly increase in E3 and E4 groups, compared to E1, E2, and E5 groups respectively (P < 0.05). The percentage of abnormal morphology, DNA fragmentation index (DFI), malondialdehyde (MDA), and the levels of ROS significantly decrease in E3 and E4 groups, compared to E1, E2, and E5 groups (P < 0.05). In addition, the sperm parameters and stress oxidative factors significantly improve in E3 group compared to other groups (P < 0.05).

CONCLUSIONS

In conclusion, the combination of Mito-Tempo with nanoliposome due to its ability to cooperate with lipid layers may lead to significant performance in reducing oxidative stress damage and increasing the quality of sperm parameters.

Poor Sperm Chromatin Condensation Is Associated with Cryopreservation-Induced DNA Fragmentation and Cell Death in Human Spermatozoa

Background/Objectives: Semen cryopreservation is routinely performed in fertility clinics for a variety of reasons, including fertility preservation and storage of donor sperm, yet the freeze-thaw process leads to cellular damage via ice crystal formation, osmotic shock, and supraphysiological levels of oxidative stress. Sperm resistance to damage during the freeze-thaw process varies widely, yet the intrinsic factors associated with sperm cryotolerance are largely unknown. The study aimed to investigate whether poor chromatin condensation renders sperm vulnerable to DNA fragmentation and cell death induced by the freeze-thaw process. Methods: Participants (n = 51) from the general community who met the inclusion criteria collected a semen sample after 3-8 days of abstinence. Neat semen samples underwent traditional semen analysis, aniline blue (AB)-eosin staining for chromatin condensation, the terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay for DNA fragmentation, and the Annexin V assay for apoptosis/necrosis, prior to being cryopreserved using the liquid nitrogen vapour method and stored at -196 °C. Stored samples were later thawed at room temperature and processed using density gradient centrifugation. Motile sperm concentration, DNA fragmentation and apoptosis/necrosis were analysed in post-thaw samples. Results: As indicated by a significant interaction effect in linear mixed models, an increased proportion of AB-positive sperm in the pre-freeze sample exacerbated the adverse effect of freezing on sperm DNA fragmentation (p = 0.004), late apoptosis (p = 0.007), and necrosis (p = 0.007). AB-staining was positively correlated with all three parameters in the post-thaw sample (all rs ≥ 0.424, all p < 0.01) and remained significant after adjusting for neat sperm concentration (all partial rs ≥ 0.493, all p < 0.01). Similarly, AB-staining was significantly correlated with the percentage point change in sperm DNA fragmentation (rs = 0.366, p = 0.014) and necrosis (rs = 0.403, p = 0.009), both of which remained significant after adjusting for neat sperm concentration (both partial rs ≥ 0.404, both p < 0.01), and borderline significantly correlated with percentage point change in late apoptosis (rs = 0.307, p = 0.051). Conclusions: Sperm with poorly condensed chromatin may be more susceptible to cellular damage during the freeze-thaw process, independent of pre-freeze sperm concentration. These findings may help to explain the intrinsic variation in sperm resistance to cryodamage within and between individuals that is poorly understood.

Assessing the Impact of the Novel Sperm Selection Technique 'Annexin-V Coated Polystyrene Bead Technique' on Mouse Assisted Reproductive Techniques Outcomes: Preliminary Findings

ICSI is one of the most commonly used techniques to treat infertility. The sperm selection for the procedure is done 'randomly' by the embryologist according to the motility and morphology parameters which is known not to reflect the potential of a sperm for fertilization, pregnancy and a healthy childbearing. Since the apoptosis rate is higher in sperm cells of infertile patients, it is more likely to choose an apoptotic sperm by the 'random selection method'. We recently introduced a novel sperm selection technique namely 'Annexin-V coated polystrene bead technique'(APB-Tech), for the selection of non-apoptotic sperm cells. The principal of the technique is based on the binding affinity of an apoptotic sperm to 'Annexin-V covered beads' enabling to distinguish a viable and a healthy sperm by light microscopy. The aim of the present study was to observe the effects of this technique on ICSI outcomes in mice. Sibling-oocyte trial was conducted and the outcome measures were compared with the results of traditional sperm selection method. Embryo and blastocyst qualities and blastocyst development rates were significantly increased in APB-Tech group, while the other parameters were not affected. Promising results obtained from the technique reflect its promising potential as a new and powerful tool for sperm selection and thus infertility techniques.

Evaluation of Sperm DNA Fragmentation Using Halosperm Technique after the Freezing-Thawing Process in Men: A Study on the Validation of the SCD Protocol

Background

DNA fragmentation index (DFI) enhances routine semen analysis by providing valuable insights into male reproductive potential. Utilizing Halosperm test, a sperm chromatin dispersion (SCD) assay based on induced condensation. The purpose of this study was to assess sperm DNA damage both before and after freezing. By following the specified kit instructions, an attempt was made to validate the SCD test protocol, with a particular emphasis on the implications of sperm freezing on its DNA integrity.

Methods

In total, 380 fresh human semen samples from normozoospermic patients were frozen at -20°C for 10 days, using SCD cryopreservation reagent. Routine semen analysis and DNA fragmentation index (DFI) were determined for each sample before freezing and after thawing. Semen morphology and sperm DFI were compared before and after freezing/thawing process.

Results

There was a significant decrease in sperm normal morphology after thawing (9.31±2.42% vs. 7.1±1.53%, p<0.05, respectively). The sperm head, midpiece, and tail defect rate increased after freezing at -20°C. Moreover, DFI was significantly higher after thawing compared to before freezing (20.71±1.61% before freezing vs. 29.1±0.21% after thawing with p<0.001).

Conclusion

Cryoconservation of semen samples at -20°C for 10 days using SCD cryopreservation reagent seems to damage sperm morphology, resulting in a reduction in sperm DNA integrity. The measurement of DFI on a fresh sample remains the most reliable technique for obtaining accurate results.

Controversy and Consensus on Indications for Sperm DNA Fragmentation Testing in Male Infertility: A Global Survey, Current Guidelines, and Expert Recommendations

PURPOSE

Sperm DNA fragmentation (SDF) testing was recently added to the sixth edition of the World Health Organization laboratory manual for the examination and processing of human semen. Many conditions and risk factors have been associated with elevated SDF; therefore, it is important to identify the population of infertile men who might benefit from this test. The purpose of this study was to investigate global practices related to indications for SDF testing, compare the relevant professional society guideline recommendations, and provide expert recommendations.

MATERIALS AND METHODS

Clinicians managing male infertility were invited to take part in a global online survey on SDF clinical practices. This was conducted following the CHERRIES checklist criteria. The responses were compared to professional society guideline recommendations related to SDF and the appropriate available evidence. Expert recommendations on indications for SDF testing were then formulated, and the Delphi method was used to reach consensus.

RESULTS

The survey was completed by 436 experts from 55 countries. Almost 75% of respondents test for SDF in all or some men with unexplained or idiopathic infertility, 39% order it routinely in the work-up of recurrent pregnancy loss (RPL), and 62.2% investigate SDF in smokers. While 47% of reproductive urologists test SDF to support the decision for varicocele repair surgery when conventional semen parameters are normal, significantly fewer general urologists (23%; p=0.008) do the same. Nearly 70% would assess SDF before assisted reproductive technologies (ART), either always or for certain conditions. Recurrent ART failure is a common indication for SDF testing. Very few society recommendations were found regarding SDF testing.

CONCLUSIONS

This article presents the largest global survey on the indications for SDF testing in infertile men, and demonstrates diverse practices. Furthermore, it highlights the paucity of professional society guideline recommendations. Expert recommendations are proposed to help guide clinicians.

Evaluation of Post-Thaw Swim-Up Selection Combined With Glutathione Addition for Improvement of Sperm Chromatin Maturity in Normozoospermic Samples

BACKGROUND

Cryopreservation of human semen alters the spermatozoal structure, resulting in a reduction in sperm function parameters. Various antioxidants may be able to slow or prevent this type of injury. Glutathione (GSH) has numerous antioxidant properties; supplementing the semen with GSH before freezing may assist in the restoration of post-thaw sperm functionality.

OBJECTIVE

 To investigate the effect of adding 5mM of glutathione before freezing on human sperm cryosurvival.

MATERIALS AND METHODS

Semen samples were collected from 30 patients (22 normozoospermic and 8 asthenozoospermic) after 3-5 days of sexual abstinence. Following liquefaction, macro- and microscopic examinations were performed. The samples were then divided into two equal aliquots: the first aliquot received 5 mM of glutathione before freezing, and the second aliquot was considered the control (without glutathione). The samples were frozen using the rapid cryopreservation method and then preserved for 7-10 days in a liquid nitrogen tank before being thawed. Thawed samples from each group were examined microscopically according to the WHO 2010 guidelines. Aniline blue was used to assess the maturity of the DNA. Then, the direct-swim-up technique was applied to thawed samples from both groups to select the best sperm quality.

RESULTS

The cryopreservation process negatively impacts all sperm characteristics in both groups. Sperm DNA integrity decreased. Glutathione addition before freezing decreased sperm chromatin immaturity (SCI) percent compared to the control (22.98 ± 0.83, 20.79 ± 0.56). The post-thaw performance of the swim-up technique resulted in a select sperm population with high progressive motility (p = 0.04) and an improvement in DNA integrity in the treated group versus the control group after thawing.

CONCLUSION

The DNA integrity in normozoospermic samples was improved by adding 5 mM glutathione before freezing. Performing the swim-up technique after thawing had no effect on sperm quality in asthenozoospermic patients.

Biomaterials for Testicular Bioengineering: How far have we come and where do we have to go?

Traditional therapeutic interventions aim to restore male fertile potential or preserve sperm viability in severe cases, such as semen cryopreservation, testicular tissue, germ cell transplantation and testicular graft. However, these techniques demonstrate several methodological, clinical, and biological limitations, that impact in their results. In this scenario, reproductive medicine has sought biotechnological alternatives applied for infertility treatment, or to improve gamete preservation and thus increase reproductive rates in vitro and in vivo. One of the main approaches employed is the biomimetic testicular tissue reconstruction, which uses tissue-engineering principles and methodologies. This strategy pursues to mimic the testicular microenvironment, simulating physiological conditions. Such approach allows male gametes maintenance in culture or produce viable grafts that can be transplanted and restore reproductive functions. In this context, the application of several biomaterials have been proposed to be used in artificial biological systems. From synthetic polymers to decellularized matrixes, each biomaterial has advantages and disadvantages regarding its application in cell culture and tissue reconstruction. Therefore, the present review aims to list the progress that has been made and the continued challenges facing testicular regenerative medicine and the preservation of male reproductive capacity, based on the development of tissue bioengineering approaches for testicular tissue microenvironment reconstruction.

Sperm cryopreservation does not affect live birth rate in normozoospermic men: analysis of 7969 oocyte donation cycles

STUDY QUESTION

Does sperm cryopreservation influence the reproductive outcomes of normozoospermic patients in oocyte donation cycles?

SUMMARY ANSWER

After controlling for confounders, the use of cryopreserved semen from normozoospermic patients does not affect pregnancy and live birth rates after elective ICSI.

WHAT IS KNOWN ALREADY

Sperm cryopreservation by slow freezing is a common practice in ART. While frozen-thawed semen typically presents reduced motility and vitality, its use for ICSI is generally considered adequate in terms of reproductive outcomes. Nevertheless, most studies comparing reproductive outcomes between fresh and cryopreserved sperm include patients with severe male factor (testicular sperm, oligo-, and/or asthenozoospermia) or women of advanced maternal age, where the altered quality of the gametes can partially mask the full effect of freezing/thawing.

STUDY DESIGN, SIZE, DURATION

The study included a retrospective cohort of 7969 couples undergoing their first oocyte donation cycle between January 2013 and December 2019 in one large clinic, using normozoospermic semen from the male partner. All cycles involved elective ICSI, fresh oocytes, and a fresh embryo transfer, either at cleavage or blastocyst stage. Two study groups were established based on the sperm status: fresh (n = 2865) and cryopreserved (n = 5104).

PARTICIPANTS/MATERIALS, SETTING, METHODS

A slow freezing protocol was used for all sperm cryopreservation. Sperm washing, capacitation, and selection prior to ICSI were performed identically for fresh and frozen-thawed samples, using pellet swim-up. Fertilization rate (FR), pregnancy (biochemical and ongoing), and live birth rates were compared between study groups using univariate and multivariate regression analyses.

MAIN RESULTS AND THE ROLE OF CHANCE

Male and female age, sperm concentration and motility after ejaculation, and number of oocytes inseminated were similar between cycles using fresh or cryopreserved sperm. Analysis by Student's t-test did not indicate a significant difference in FR between fresh and cryopreserved sperm (P = 0.0591); however, after adjusting for confounders, this difference reached statistical significance: 74.65% FR for fresh (CI 95%: 73.92-75.38) versus 73.66% for cryopreserved sperm (CI 95%: 73.11-74.20), P = 0.0334. The adjusted regression analysis revealed higher odds of biochemical pregnancy when using fresh sperm (odds ratio (OR): 1.143, P = 0.0175), but no significant effects of sperm cryopreservation were observed for ongoing pregnancy (OR: 1.101, P = 0.0983) and live birth (OR: 1.082, P = 0.1805).

LIMITATIONS, REASONS FOR CAUTION

Caution should be exerted when extrapolating these results to different protocols for sperm cryopreservation and selection, or to IVM, advanced maternal age and classical IVF cycles, which were excluded from analysis. Owing to the retrospective nature of the study, some uncontrolled for variables may affect the results.

WIDER IMPLICATIONS OF THE FINDINGS

Sperm cryopreservation does not affect pregnancy and live birth rates in normozoospermic patients, and although it may lower FR s slightly, this would not be clinically relevant. In line with previous studies that included patients with an apparent male or female factor, sperm cryopreservation is a safe and convenient technique.

STUDY FUNDING/COMPETING INTEREST(S)

The study received no external funding and all authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Cryopreservation of Human Spermatozoa: Functional, Molecular and Clinical Aspects

Cryopreservation is an expanding strategy to allow not only fertility preservation for individuals who need such procedures because of gonadotoxic treatments, active duty in dangerous occupations or social reasons and gamete donation for couples where conception is denied, but also for animal breeding and preservation of endangered animal species. Despite the improvement in semen cryopreservation techniques and the worldwide expansion of semen banks, damage to spermatozoa and the consequent impairment of its functions still remain unsolved problems, conditioning the choice of the technique in assisted reproduction procedures. Although many studies have attempted to find solutions to limit sperm damage following cryopreservation and identify possible markers of damage susceptibility, active research in this field is still required in order to optimize the process. Here, we review the available evidence regarding structural, molecular and functional damage occurring in cryopreserved human spermatozoa and the possible strategies to prevent it and optimize the procedures. Finally, we review the results on assisted reproduction technique (ARTs) outcomes following the use of cryopreserved spermatozoa.

Pentoxifylline treatment had no detrimental effect on sperm DNA integrity and clinical characteristics in cases with non-obstructive azoospermia

The aim of this study was to assess the consequences of treatment with pentoxifylline (PTX), an inducer of sperm motility, on sperm DNA fragmentation (SDF) and clinical characteristics in non-obstructive azoospermia (NOA) patients. The pilot study included 15 NOA patients. Half of each sperm sample before and after rapid freezing, was treated with PTX (3.6 mM /l, 30 min) as the PTX group and the remaining samples were considered as the control. SDF and sperm motility were assessed in each group. The clinical study comprised 30 fresh testicular sperm extractions (TESE) and 22 post-thawed TESE intracytoplasmic sperm injection cycles. Half of the mature oocytes from each patient were injected with PTX-treated spermatozoa and the remaining oocytes were injected with non-treated spermatozoa. Fertilization was assessed at 16 h post injection. Embryo transfer was carried out on day 2 after fertilization. Chemical pregnancy was assessed 2 weeks after transfer. PTX was found to significantly increase (P < 0.05) sperm motility. There was an insignificant difference in SDF rates between the groups (P > 0.05). In patient ovaries given fresh TESE, there was not any significant difference in clinical characteristics (P > 0.05). In patient ovaries given post-thawed TESE, there was a significant difference in the number of 2PN and in embryo formation (P < 0.05). Differences in the results of chemical pregnancy were insignificant (P > 0.05) between the groups. In addition, there was not any correlation between DNA fragmentation index and sperm motility and laboratory outcomes. Therefore, obtaining viable spermatozoa using PTX was more effective in post-thawed TESE regime patients in terms of 2PN and in embryo formation, deprived of damaging effects on sperm DNA integrity.

Combination of nanoparticle green tea extract in tris-egg yolk extender and 39 °c thawing temperatures improve the sperm quality of post-thawed Kacang goat semen

Kacang goats are small ruminants produced by low-income households in smallholder and farm to reduce poverty and prevent undernutrition. Studies to find a cryopreservation protocol for Kacang goat semen are expected to multiplication of genetically superior animals selected by the paternal lineage. This study evaluated the effect of thawing temperature and supplementation of the green tea extract nanoparticle in skim milk-egg yolk (SM-EY) extender on post-thaw sperm quality of Kacang goat semen. Six ejaculates of Kacang goat were diluted in SM-EY supplemented or not (control group) with 0.001 mg/mL NPs GTE. The diluted semen was packaged with 0.25 mL straws (insemination dose: 60x10⁶ sptz/mL) and cryopreserved. Then, six samples of the control group and NPs GTE groups were thawed at 37°C or 39°C sterile water for 30 s and submitted to sperm quality evaluations. The sperm viability, motility, and intact of the plasma membrane (IPM) were higher (p<0.05) in NPs GTE group than control group. In contrast, the NPs GTE group presented lower (p<0.05) malondialdehyde levels and sperm DNA fragmentation (SDF) compared with the control group. The catalase levels were not significantly different (p > 0.05) between the control and NPs GTE groups. Thawing at 39°C resulted in higher (p<0.05) sperm viability, motility, and IPM than thawing at 37°C. However, thawing at 39°C group presented lower (p<0.05) malondialdehyde levels compared with thawing at 37°C. SDF and catalase levels were similar (p>0.05) between thawing at 37°C and thawing at 37°C. In conclusion, supplementation of 0.001 mg/mL of NPs GTE in SM-EY extender and thawing temperature of 39°C resulted in a better quality of frozen-thawed Kacang goat semen.

Synchronous Testicular Sperm Extraction in the Setting of Bladder Exstrophy

Bladder exstrophy (BE) is a devastating congenital abnormality of the urinary tract in which infants are born with the urinary bladder extruded through their abdominal wall, a urethra that is open dorsally, and significant secondary abnormalities of the genitalia. We present a male patient with BE who suffered from infertility and after a long course of failed attempts with assisted reproductive technology ultimately benefitted from a synchronous testicular sperm extraction. We review the literature surrounding assisted reproductive techniques in the setting of bladder exstrophy and comment on innovative technologies that may benefit this population.

Advanced Paternal Age and Future Generations

Paternal age at conception has been increasing. In this review, we first present the results from the major mammalian animal models used to establish that increasing paternal age does affect progeny outcome. These models provide several major advantages including the possibility to assess multi- transgenerational effects of paternal age on progeny in a relatively short time window. We then present the clinical observations relating advanced paternal age to fertility and effects on offspring with respect to perinatal health, cancer risk, genetic diseases, and neurodevelopmental effects. An overview of the potential mechanism operating in altering germ cells in advanced age is presented. This is followed by an analysis of the current state of management of reproductive risks associated with advanced paternal age. The numerous challenges associated with developing effective, practical strategies to mitigate the impact of advanced paternal age are outlined along with an approach on how to move forward with this important clinical quandary.

Outcomes of Frozen Oocyte Donor In Vitro Fertilization (IVF) Cycles Using Fresh Versus Frozen Sperm

The ability to use frozen sperm for insemination during in vitro fertilization (IVF) is crucial for patients and for reproductive endocrinologists. However, concerns exist regarding the effects of cryopreservation on sperm quality and IVF outcomes. This study compares outcomes of frozen donor oocyte IVF cycles with intracytoplasmic sperm injection (ICSI) of good quality fresh versus frozen ejaculated sperm. Patients who underwent their first frozen donor oocyte IVF cycle between 2013 and 2019 at Mayo Clinic were identified. The primary outcome was live birth rate (LBR). Secondary outcomes included fertilization rate (FR), blastocyst development rate (BR), and clinical pregnancy rate (CPR). Twenty-six patients used fresh sperm and 19 patients utilized frozen sperm; there were no significant demographic differences between the groups. There were no significant differences noted in CPR, FR, and BR. Although the LBR was not statistically different when frozen versus fresh sperm was utilized (52.6% vs. 61.5%, p = 0.55), there was a distinct trend towards improved outcomes with fresh sperm that may be clinically significant. This data suggests that frozen sperm may be an alternative to a fresh sample, however fresh sperm may ultimately be a better option. This finding should be further explored with studies utilizing a larger sample size.

Normal seminal plasma could preserve human spermatozoa against cryopreservation damages in Oligozoospermic patients

BACKGROUND

Cryopreservation of human spermatozoa has been identified as an efficient procedure to preserve fertility in men before any cancer therapy or surgical infertility treatment. Despite the benefits of the procedure, the deleterious effects of cryopreservation have been proven on sperm structure and function. This study aimed to evaluate seminal plasma effects on human sperm characteristics after cryopreservation, and compare the addition of normozoospermic and oligozoospermic seminal plasma in the prepared oligozoospermic samples. Semen samples were collected from fifty-five oligozoospermic men and the twenty fertile individuals who referred to the infertility center. At first, a semen analysis was carried out on each neat ejaculate, and then some were cryopreserved. The remainder of the semen was divided into two, one for seminal plasma removal and the other for sperm preparation. Then, the prepared spermatozoa were cryopreserved in three groups: one with, and another without the addition of oligozoospermic seminal plasma, and still another with the addition of normal seminal plasma. After thawing, sperm DNA integrity, viability, motility, and morphology were determined.

RESULTS

The percentages of all parameters were significantly lower after cryopreservation in all groups compared to the fresh sample. However, this reduction was lower in the oligozoospermic samples cryopreserved with normal seminal plasma.

CONCLUSION

The results indicated that seminal plasma in oligozoospermic patients could not support sperm against cryo-injuries, an indication likely due to insufficient antioxidants and other protective components in oligozoospermic patients. However, normal seminal plasma could slightly preserve sperm characteristics after cryopreservation in oligozoospermic patients.

Social sperm freezing

Increased paternal age has been associated with lower fertility and higher genetic risk for the offspring. One way to prevent these consequences is to freeze sperm at a young age. Social sperm freezing could be developed in a way similar to social oocyte freezing. The main difference between freezing oocytes and sperm is that social sperm freezing is much less focussed on fertility preservation and much more on avoiding increased genetic risk. Contrary to what some people seem to believe, sperm freezing is more complicated than it looks at first sight. This article considers three practical aspects: freezing, storage and testing. It is concluded that the remedy (cryopreservation) may itself cause damage to the quality of the spermatozoon and to its genetic integrity, thus undoing the possible benefits in terms of fertility and health of offspring.

Time-lapse imaging of human embryos fertilized with testicular sperm reveals an impact on the first embryonic cell cycle

Testicular sperm is increasingly used during in vitro fertilization treatment. Testicular sperm has the ability to fertilize the oocyte after intracytoplasmic sperm injection (ICSI), but they have not undergone maturation during epididymal transport. Testicular sperm differs from ejaculated sperm in terms of chromatin maturity, incidence of DNA damage, and RNA content. It is not fully understood what the biological impact is of using testicular sperm, on fertilization, preimplantation embryo development, and postimplantation development. Our goal was to investigate differences in human preimplantation embryo development after ICSI using testicular sperm (TESE-ICSI) and ejaculated sperm. We used time-lapse embryo culture to study these possible differences. Embryos (n = 639) originating from 208 couples undergoing TESE-ICSI treatment were studied and compared to embryos (n = 866) originating from 243 couples undergoing ICSI treatment with ejaculated sperm. Using statistical analysis with linear mixed models, we observed that pronuclei appeared 0.55 h earlier in TESE-ICSI embryos, after which the pronuclear stage lasted 0.55 h longer. Also, significantly more TESE-ICSI embryos showed direct unequal cleavage from the 1-cell stage to the 3-cell stage. TESE-ICSI embryos proceeded faster through the cleavage divisions to the 5- and the 6-cell stage, but this effect disappeared when we adjusted our model for maternal factors. In conclusion, sperm origin affects embryo development during the first embryonic cell cycle, but not developmental kinetics to the 8-cell stage. Our results provide insight into the biological differences between testicular and ejaculated sperm and their impact during human fertilization.

Green tea extract increases the quality and reduced DNA mutation of post-thawed Kacang buck sperm

The study aimed to determine the addition of green tea extract (GTE) in extender on the quality and DNA mutation of post-thawed Kacang buck sperm. The sperm DNA mutation was observed on nicotinamide adenine dinucleotide hydride (NADH) dehydrogenase 1 (ND1) of mitochondrial Deoxyribonucleic Acid (mtDNA). A pool of 12 Kacang buck ejaculates was diluted in skim milk-egg yolk extender contained 0, 0.05, 0.10, and 0.15 mg of GTE/100 mL for T0, T1, T2, and T3 group, respectively. Each of the aliquot groups was packaged in 0.25 mL French mini straw contained 60 million alive sperm and froze according to the protocol. The ND1 mtDNA amplification of samples was carried out Polymerase Chain Reaction machine, followed by DNA sequencing using the Sanger method. Meanwhile, the phylogenetic tree was constructed using the neighbor-joining (NJ) method with MEGA 7.0 software. The results showed that the T2 group maintained the highest quality for Kacang buck post-thawed semen. There was the highest percentages of sperms viability, motility, intact plasma membrane (IPM), the lowest of malondialdehyde (MDA) concentration, sperm DNA fragmentation (SDF), the total and types of ND1 mtDNA mutation frequency. The phylogenetic tree analysis revealed that the clade of the T2 group was most closely related to the sequence reference. However, there was no correlation between the semen quality parameters (sperm viability, motility, IPM, MDA concentration, and SDF) with ND1 mtDNA mutation of post-thawed Kacang buck semen. It could be concluded that GTE was useful as an antioxidant for Kacang buck semen extender for frozen sperm.

Best laboratory practices and therapeutic interventions to reduce sperm DNA damage

Conventional semen analysis is considered the cornerstone investigation for infertile men. Nonetheless, this routine test does not provide information on important sperm functions like sperm DNA fragmentation (SDF). Abnormalities of human spermatozoal nucleus and chromatin have a detrimental impact on both natural and assisted reproductive outcomes. In vivo, SDF results from abnormalities in chromatin compaction, abortive apoptosis and oxidative stress, while in vitro, a number of factors may be implicated. Various SDF testing methods are available, and the most commonly utilised assays include terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL), sperm chromatin dispersion (SCD) test, sperm chromatin structure assay (SCSA) and Comet assay. SDF testing has shown beneficial effects on treatment decision-making; however, its routine use in the initial evaluation of infertile men is still not recommended. One of the treatment options to reduce sperm DNA damage is the use of antioxidants. Despite the documented improvement in semen parameters and sperm DNA integrity following antioxidant therapy, no definitive recommendation is reached due to lack of large, well-designed, randomised, placebo-controlled trials assessing their exact role in male factor infertility. The objectives of this review article are to illustrate the aetiologies of SDF, to describe the effects of SDF on male factor fertility, to explore the common techniques utilised in SDF testing, to review the clinical indications for SDF testing and to review the effect of antioxidant therapy as a method to alleviate SDF.

Sperm protein markers for Holstein bull fertility at National Artificial Insemination Centers in Indonesia

BACKGROUND AND AIM

Holstein cows and heifers are widely bred in Indonesia by artificial insemination (AI) to increase population and milk production. Sperm fertility is modulated by genetic factors, but the analysis of sperm quality is still based on macro- and microscopic characteristics. This study aimed to analyze both sperm quality and proteins of Holstein bulls at different fertility levels.

MATERIALS AND METHODS

The frozen semen samples were collected from the Indonesia National AI Center. They were classified based on the reproductive efficiency data and were grouped into high fertile (HF) and low fertile (LF). Sperm qualities were evaluated by microscopic evaluation. The Holstein sperm proteins were extracted using phenylmethanesulfonyl fluoride as a protease inhibitor and the benzidine detergent extraction method. Discontinuous sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was conducted to analyze the molecular weights (MWs) of the sperm proteins. The data obtained were analyzed by a t-test using the one-factor bull fertility level, and Spearman's correlation analysis was used to identify the correlation between the sperm microscopic evaluation parameters and protein bands.

RESULTS

The sperm motility post-freeze thawing was not significantly different between the HF and LF (p>0.05). The HF level had a higher percentage of viability, intact plasma membrane integrity, and intact acrosomes than the LF (p<0.05). Five protein bands were found in the SDS-PAGE of sperm proteins of Holstein bulls with different concentrations. Sperm proteins with MWs of 17.51 kDa, 14.87 kDa, 33.71 kDa, and 41.97 kDa were abundant in the Holstein bulls with an HF level, while 55 kDa proteins were abundant in the LF level of Holstein bulls. The sperm of Holstein bulls in the HF level contained proteins of about 33.71 kDa that were not detected in the LF.

CONCLUSION

The sperm protein with a molecular weight of 33.71 kDa was predicted to be a specific protein biomarker that influences bull fertility. Sperm fertilization abilities were also determined by the sperm proteins, the morphology of sperm acrosomes, and the quality of plasma membranes. This method can be used to select bulls with high fertility to increase the population of Holstein bulls.

DNA fragmentation index (DFI) as a measure of sperm quality and fertility in mice

Although thousands of genetically modified mouse strains have been cryopreserved by sperm freezing, the likelihood of cryorecovery success cannot be accurately predicted using conventional sperm parameters. The objective of the present study was to assess the extent to which measurement of a sperm DNA fragmentation index (DFI) can predict sperm quality and fertility after cryopreservation. Using a modified TUNEL assay, we measured and correlated the DFI of frozen-thawed sperm from 83 unique mutant mouse strains with sperm count, motility and morphology. We observed a linear inverse correlation between sperm DFI and sperm morphology and motility. Further, sperm DFI was significantly higher from males with low sperm counts compared to males with normal sperm counts (P < 0.0001). Additionally, we found that viable embryos derived using sperm from males with high DFI (62.7 ± 7.2% for IVF and 73.3 ± 8.1% for ICSI) failed to litter after embryo transfer compared to embryos from males with low DFI (20.4 ± 7.9% for IVF and 28.1 ± 10.7 for ICSI). This study reveals that measurement of DFI provides a simple, informative and reliable measure of sperm quality and can accurately predict male mouse fertility.