The Protective Effects of Alpha Lipoic Acid on Human Sperm Function During Freezing-Thawing

BACKGROUND

Sperm cryopreservation is presently used for conservation of male gametes in assisted reproduction technologies (ART). Despite the benefits of sperm banking, freeze-thawing process is injurious to sperm integrity due to induced oxidative stress by cold stress. Oxidative stress reduces sperm motility, viability and DNA integrity.

OBJECTIVE

To investigate the effect of alpha lipoic acid (ALA) on human sperm function during the freeze-thawing process.

MATERIALS AND METHODS

Thirty semen samples were collected and different concentrations (0, 0.05, 0.1, 0.2, 0.4, 0.8, and 8mM) of ALA were added to a sperm freeze medium and its effects on sperm motility, DNA damage, and lipid peroxidation of frozen-thawed spermatozoa were assessed.

RESULTS

The addition of 0.2 mM ALA to the sperm freeze medium resulted in significant improvement in percentage of sperm motility, less DNA damage and decreased lipid peroxidation during freeze-thawing process (p<0.05).

CONCLUSION

ALA improves the cryo-protective capacity of sperm freeze medium used for human semen by protecting the sperm from ROS attack induced by the freezing-thawing process. We suggest that sperm freeze medium supplemented with 0.2 mM ALA would be beneficial for the cryopreservation of male gametes in ART.

Could high DNA stainability (HDS) be a valuable indicator of sperm nuclear integrity?

Background

The Sperm Chromatin Structure Assay (SCSA®), in addition to identifying the DNA Fragmentation Index (DFI) also identifies High DNA satiability (HDS), supposed to reflect the nuclear compaction of spermatozoa. However, data on what exactly this parameter reveals, its relevance and usefulness are contradictory. In order to shed light on this situation, spermatozoa of a cohort (N = 397) of infertile men were subjected to the SCSA®, TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling) and CMA3 (Chromomycin A3) tests. In a smaller subcohort (N = 100), aniline blue (AB) and toluidine blue (TB) staining were performed in addition. The objective of this study was thus to answer the question of whether HDS is a relevant and reliable parameter to be taken into account?

Results

HDS does not appear to be a reliable indicator of nuclear immaturity because it shows a weak correlation with the CMA3, AB and TB stains. The low correlation of HDS with sperm DNA fragmentation (TUNEL and SCSA®) and DNA condensation (CMA3, AB and TB) tests suggests that these two parameters could be decoupled. Unlike DFI and TUNEL, HDS has not been shown to correlate with classic clinical situations of male infertility (asthenozoospermia, teratozoospermia or astheno-teratozoospermia).

Conclusion

HDS correlates poorly with most tests that focus specifically on the level of maturity of the sperm nucleus. To our knowledge, this study is the first to compare SCSA®, TUNEL, AB, TB and CMA3 assays on identical samples. It shows the potency, consistency and limitations of each test and the care that must be taken in their interpretation.

Association between total globozoospermia and sperm chromatin defects

Globozoospermia is a severe sperm morphological anomaly leading to primary infertility and low fertilisation following intracytoplasmic sperm injection (ICSI). This phenotype is observed in less than 0.1% of infertile men and is determined by small, round-headed spermatozoa with absence of an acrosomal cap, acrosome protease and also cytoskeletal proteins. Failure of oocyte activation is considered as the main cause of fertilisation failure in these individuals post-ICSI. Therefore, artificial oocyte activation (AOA) along with ICSI is commonly implemented. However, based on previous report, fertilisation rate remains low despite implementation of ICSI-AOA. Therefore, other mechanisms like sperm chromatin packaging and DNA fragmentation may account for low fertilisation and development post-ICSI-AOA. Therefore, this study aims to assess and compare the degree of sperm protamine deficiency and DNA fragmentation in large population of infertile men with total globozoospermia (30 globozoospermic men presenting with 100% round-headed spermatozoa) with 22 fertile individuals using chromomycin A3 and TUNEL assay respectively. Results clearly show that mean of sperm concentration and percentage of sperm motility were significantly lower, while percentage of sperm abnormal morphology, protamine-deficient and DNA-fragmented spermatozoa were significantly higher in infertile men with globozoospermia compared to fertile men. Therefore, increased sperm DNA damage in globozoospermia is likely related to defective DNA compaction and antioxidant therapy before ICSI-AOA could be recommended as an appropriate option before ICSI-AOA.

Effects of Tempol and Quercetin on Human Sperm Function after Cryopreservation

　　BACKGROUND: Quercetin is a flavonoid with high reactive oxygen species (ROS) scavenging and ion chelating activity. It also enhances the activity of antioxidant enzymes and reduces enzymatic activity such as NADPH oxidase and NADH-dependent oxido-reductase. Tempol, as a superoxide dismutase mimetic agent, converts superoxide to less toxic hydrogen peroxide (H₂O₂), but cannot reduce highly toxic hydroxyl radicals in Fenton or Haber-Weiss reactions mediated with free iron or cupper.

OBJECTIVE

The study was to compare the effect of Quercetin and Tempol in an optimized commercial cryo-protective media on ROS induced cryoinjury for the first time.

MATERIALS AND METHODS

Following administration of these compounds during freezing process, sperm motility, viability, ROS production and DNA integrity were assessed before and after freezing/thawing process.

RESULTS

Data showed that 10 µM Quercetin and 5 µM Tempol significantly improved sperm motility and viability, but they together had no additive effect. Supplementation with Quercetin alone or combination of Quercetin with Tempol decrease the ROS concentration, but the reduction was not significant for Tempol alone compared to control group. Quercetin and Tempol significantly decrease DNA fragmentation.

CONCLUSION

The supplementation of Quercetin or Tempol, but not their combination improves the quality of cryopreserved human semen.

Zeta potential vs apoptotic marker: which is more suitable for ICSI sperm selection?

PURPOSE

Selection of appropriate sperm is considered as a decision making point in the ICSI procedure. Canonically, sperm selection is based on morphology and motility. Recent advances in this field, have shown that, this procedure can be assisted by further selection based on membrane surface charge (Zeta potential) and surface apoptotic marker (phosphatidylserine externalization) using magnetic activated cell sorter (MACS). Based on the literature, both these procedures improve quality of selected sperm population. Therefore, this study aims to compare the efficiency of these two procedures.

METHODS

Semen samples were collected from 36 fertile and infertile (teratozoospermic and /or asthenozoospermic) individuals. Sperm DNA fragmentation, protamine deficiency and morphology were assessed by TUNEL, CMA3 and papanicolaou staining in unprocessed, MACS and Zeta processed samples.

RESULTS

Although both MACS and Zeta were able to separate a higher percentage of sperm with normal morphology, and lower DNA fragmentation and protamine deficiency compared to unprocessed, MACS procedure could significantly isolate, a greater percentage of sperm with normal acrosome and protamine content compared to Zeta procedure.

CONCLUSION

Both MACS and Zeta procedures improve the quality of the selected spermatozoa for ICSI. However, MACS procedure is more efficient in individuals with severe male factor infertility to select sperm with normal acrosome and protamine content but concern regarding transfer of MACS beads into the oocyte remains to be resolved.

Sperm ubiquitination and DNA fragmentation in men with occupational exposure and varicocele

Assessment of sperm ubiquitination and DNA fragmentation as sperm functional markers are proposed to complement routine semen analysis. This study focuses on the evaluation of these markers in infertile men with varicocele or exposed to occupational background. The results were compared with normozoospermic men. Semen parameters in both groups were lower than those in the control group. Ubiquitination median, as a marker for functionality of the ubiquitin-proteasome system, was also lower in both groups. The ubiquitination median showed a significant positive correlation with motility in both groups, while it showed only a negative correlation with sperm morphology in the varicocele group. DNA fragmentation showed a significant correlation with semen parameters, in total varicocele and also total exposure groups. In conclusion, significant difference of sperm ubiquitination between normal and study groups further validates that sperm ubiquitination as a potential molecular marker for sperm evaluation in addition to routine semen analysis in clinical laboratories.

Relationship between fertilization rate and early apoptosis in sperm population of infertile individuals

Integrity of the sperm membrane, of which phosphatidyl serine (PS) plays a central role, is essential for fertilization. The externalisation of PS (EPS) occurs during capacitation and the acrosome reaction. EPS, from the inner to the outer membrane, is considered as a sign of early apoptosis. Therefore, EPS may have a dual function in sperm. This study has evaluated the relationship between EPS and fertilization, embryo quality and pregnancy outcomes in couples who were candidates for ICSI. Semen samples were collected from 43 ICSI candidates and assessed according to World Health Organization guidelines for semen parameters. EPS was assessed by Annexin V and propidium iodide (PI) staining. Protamine deficiency was assessed by chromomycin A3 (CMA3) staining. A significant positive correlation was observed between the percentages of fertilization and annexin-positive PI-negative (An(+)PI(-)) sperm. There was a significant negative correlation between the percentages of protamine-deficient sperm with the percentage of fertilization. In addition, the percentage of An(+)PI(-) sperm in individuals with fertilization rates higher and lower than 50% significantly differed. The percentage of annexin-positive PI-positive (An(+)PI(+)) sperm in semen of the partners of pregnant women significantly differed from the partners of nonpregnant women. In conclusion, if An(+)PI(-) is a sign of capacitation and An(+)PI(+) is a sign of apoptosis, the results suggest that semen samples with a higher ability to undergo capacitation have a higher chance to result in successful fertilization post-ICSI. The presence of a high percentage of apoptotic sperm in the insemination sample before capacitation may reduce the chances of pregnancy.

Is there an association between HOST grades and sperm quality?

BACKGROUND

Intracytoplasmic sperm injection (ICSI) is the primary treatment for male infertility. However for this procedure, with the exception of visual morphological selection, there is no standardization for sperm selection. Recently, the hypo-osmotic swelling test (HOST) has been proposed to potentially select sperm with intact membranes. The aim of this study is to evaluate the ability of this technique to select functional sperm in terms of apoptosis and morphology, as well as nuclear integrity.

METHODS

A total of 20 semen samples were randomly collected from men who attended the Andrology Unit of the Isfahan Fertility and Infertility Center. Semen samples were washed and exposed to hypotonic conditions, before being fixed and simultaneously assessed for membrane integrity as well as abnormal morphology, DNA fragmentation and protamine deficiency by using Papanicolaou, TUNEL and CMA3 staining techniques, respectively. The remaining semen samples were washed with calcium buffer and stained by Annexin V, then exposed to hypotonic conditions before being assessed for early apoptosis along with membrane integrity.

RESULTS

HOST grade 'd', followed by grade 'c', showed the highest percentages of healthy sperm, whereas sperm of HOST grade 'g' in which anomalies in terms of apoptosis, abnormal head morphology or nuclear immaturity or membrane damage, were most frequently observed in the samples assessed.

CONCLUSIONS

Integration of HOST into the sperm selection procedure may provide a valuable tool for selection of functional sperm required for ICSI. According to this study, insemination of HOST grade 'g' sperm should be avoided during ICSI.

High total acrosin activity in varicocele individuals

Varicocele is a common cause of male infertility and reports indicate that varicocelectomy has a beneficial effect on male fertility. The aims of this study were to evaluate and compare the total acrosin activity along with DNA integrity in semen samples obtained from 70 varicocele individuals with male factors infertility presenting grades II and III varicocele before and after the surgery and 30 fertile individuals without any clinical presentation of varicocele. Total acrosin activity, protamine deficiency, DNA fragmentation, and semen parameters including sperm concentration, motility and sperm morphology were assessed by spectrophotometery, CMA3 staining, terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay and WHO criteria, respectively. Total acrosin activity (P = 0.03), percentage CMA3 positivity (P = 0.00) and TUNEL-positive spermatozoa (P = 0.04) were higher in the varicocele individuals before the surgery compared with the fertile individuals; yet, all the aforementioned criteria decreased significantly after surgery (P < 0.05). The results of this study reveal that DNA fragmentation and protamine deficiency, as negative parameters in fertility, improve post-surgery; however, total acrosin activity as a positive parameter in fertility is higher in the varicocele individuals compared with fertile and decreases to a value close to the fertile control post-surgery. High levels of total acrosin activity in varicocele individuals need more research in future.

Zaditen (Ketotifen), as mast cell blocker, improves sperm quality, chromatin integrity and pregnancy rate after varicocelectomy

Surgery is considered the most common choice for the treatment of male infertility with clinical varicocele. Increased numbers of mast cells (MCs) have been associated with different types of infertility, including varicocele. Despite there being different reports on improved fertility following administration of MC blockers, there is no report on the effect of a MC blocker on varicocele or after varicocelectomy. Therefore, the aim of this study was to evaluate the effect of Zaditen on semen quality, protamine content, DNA damage and fertility post-surgery. The study included 103 infertile men who were referred to Isfahan Fertility and Infertility Center for varicocelectomy. Varicocele individuals were randomly divided into control (52) and treatment groups (51). Semen parameters, WBC/mL, protamine content (chromomycin A3 staining) and DNA integrity (sperm chromatin dispersion test) were assessed before and 3 months after surgery. Comparison of the aforesaid parameters between the two groups revealed significant improvement in the treatment group compared with the control group, with the exception of DNA integrity. In addition, the cumulative pregnancy significantly improved by 9 months post-surgery in the treatment group (41.17%) compared with the control group (21.15%). The results of this study, for the first time, reveal that MC blockers such as Zaditen improve semen parameters, chromatin integrity and pregnancy rates when administered as adjunct therapy post-varicocelectomy.

Quantitative expression of phospholipase C zeta, as an index to assess fertilization potential of a semen sample

BACKGROUND

Failed fertilization post-ICSI has been mainly attributed to the sperm's inability to induce oocyte activation. Phospholipase C zeta (PLCζ) is considered to be one of the factors for the induction of oocyte activation. The aim of this study was to quantitatively assess the expression of PLCζ in globozoospermic men or those with previously low or failed fertilization in comparison with fertile men or those with high fertilization potential. In addition, the relationship between expression of PLCζ and that of other sperm markers was evaluated.

METHODS

Real-time PCR was carried out to evaluate relative expression of PLCζ mRNA. Chromatin maturity and acrosin activity were assessed by CMA3 staining and a colorimetric method.

RESULTS

The expression of PLCζ was significantly lower in globozoospermic men (P< 0.01, n= 8) or individuals with previously low or failed fertilization (P< 0.01, n= 36) in comparison to fertile men (n= 24). In addition, a significant difference was observed between globozoospermic (P< 0.01) and individuals with previously low or failed fertilization (P= 0.003) in comparison to high fertilization individuals (n= 17). Expression of PLCζ was not correlated with either chromatin maturity or acrosin activity. However, a significant correlation was observed between the percentage of fertilization and relative expression of PLCζ (r= 0.4, P< 0.01).

CONCLUSION

In this study, for the first time, we have shown that assessment of relative expression of PLCζ may provide a useful marker for the ability of sperm to induce oocyte activation after ICSI.

Evaluation of sperm selection procedure based on hyaluronic acid binding ability on ICSI outcome

PURPOSE

To compare the efficiency of routine sperm selection method with HA-selection procedure for fertilization rate, embryo development, implantation and pregnancy rates as well as evaluating the relationship between HA-binding ability with sperm protamine deficiency and DNA fragmentation.

METHODS

Semen samples were obtained from the 50 couples undergoing ICSI. The percentage of fertilization rate, cleavage and quality of embryos compared between two procedures (routine sperm selection and HA-binding selection). The semen samples were assessed for DNA fragmentation and protamine deficiency by sperm chromatin dispersion (SCD) test and Chromomycin A3 (CMA3) staining, respectively.

RESULTS

A significant inverse correlation was observed between percentage of HA binding with protamine deficiency, DNA fragmentation and abnormal sperm morphology (P < 0.05). Furthermore, in current study, oocytes inseminated by HA sperm selection procedure had significantly higher fertilization rate (P < 0.05). While the pregnancy and implantation rates were insignificantly increased.

CONCLUSION

The results suggest that normal sperm have higher chance to bind HA and therefore, HA sperm selection procedure may select sperm with normal protamine content and low DNA fragmentation, but to confirm the effect of HA sperm selection on the ICSI outcome requires further studies.