In vitro effects of pentoxifylline and coenzyme Q10 on the sperm of oligoasthenoteratozoospermia patients

The effect of in-vitro sperm incubation with Pentoxifylline (PTX) and Coenzyme Q10 (CoQ10) in Oligoasthenoteratozoospermia (OAT) patients was evaluated. Semen samples were obtained from men with Normozoospermia and men with OAT. Motile sperm from the two groups were subdivided into four subgroups: (i) without incubation with PTX + CoQ10; (ii) incubation with PTX; (iii) Incubation with CoQ10; and (iv) incubation with a combination of PTX + CoQ10. Then, sperm parameters, chromatin, DNA and membrane integrity, protamine deficiency, apoptosis, mitochondrial activity, sperm chromatin dispersion test (SCD), hypo-osmotic swelling test (HOS), chromomycin A3 (CMA3), Terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL), and diaminobenzidine (DAB) assays were evaluated, respectively. Sperm incubated with CoQ10 and a combination of CoQ10 and PTX resulted in a significant increase in the sperm parameters. Also, a significant decrease was noted with a combination of PTX and CoQ10 in normal men. There was a significant difference between CoQ10 treated and CoQ10 + PTX treated groups in comparison with the OAT group in the percentage of the DNA fragmentation, sperm apoptosis, AB+, HOS test + and sperm mitochondrial activity. Incubated sperm with CoQ10, PTX, and in combination with each other can improve sperm parameters in OAT patients.

Protective Effects of Trehalose and Pentoxifylline on Goat Sperm Exposed to Chilling-Freezing Process

Freezing of sperm is known as an important part of assisted reproduction. However, many studies have illustrated that cryopreservation negatively affects the quality and fertility rate of sperm. This study aimed to evaluate the effects of trehalose and pentoxifylline (PTX) in diluents on cooled and frozen-thawed Markhoz goat sperm. Preassessed samples were pooled and diluted with a basic diluent using trehalose and PTX. The cooled sperm showed significant improvement. The motion characteristics of cryopreserved sperm were evaluated based on computer-assisted system analysis. In this study, we investigated the viability, membrane integrity, malondialdehyde concentration, total abnormality, acrosome integrity, and seminal hyaluronidase enzyme. Also, the hypo-osmotic swelling test, mitochondrial activity, apoptotic features, caspase activity, chromatin dispersion test, active mitochondria, and reactive oxygen species (ROS) activity were assessed as complementary parameters. The data illustrate that the total motility, progressive motility, average path velocity (VAP), straight-line velocity (VSL), curvilinear velocity (VCL), and the ratio of sperm chromatin dispersion, viable sperm were improved significantly (p < 0.05) using 3 mM PTX alone or 3 mM PTX plus 50 mM trehalose, while other characteristics indicate significant enhancement by 3 and 6 mM PTX and 50 and 70 mM trehalose alone or in combination, except amplitude of lateral head displacement (ALH), beat/cross frequency (BCF), and intracellular ROS-(O^-), which demonstrate no significant difference among treatments. In conclusion, this study indicates that addition of 3 and 6 mM PTX alone or with 50 and 70 mM trehalose seems to reduce the damage caused by cooling and cryopreservation processes.

Role of exogenous antioxidants on the performance and function of pig sperm after preservation in liquid and frozen states: A systematic review

In situations where an excessive generation of reactive oxygen species overwhelms antioxidant capacity, a harmful effect on sperm function is exerted. Antioxidants are molecules capable of minimizing this detrimental effect, which is important in pig sperm due to the high content of polyunsaturated fatty acids in their plasma membrane. The present systematic review aims at evaluating whether supplementing semen extenders (for liquid storage at 17 °C) or freezing and/or thawing media (for cryopreservation) with antioxidants influences sperm quality and functionality parameters, and in vitro/in vivo fertility outcomes. We defined inclusion and exclusion criteria in a PICOS table according to PRISMA guidelines, and conducted a literature search through MEDLINE-PubMed in November 2020. After systematic selection, 75 studies were included: 47 focused on cryopreservation and 28 on liquid storage at 17 °C. More than 70% of the studies included in this review showed that adding semen extenders for liquid storage and/or freezing/thawing media for cryopreservation with antioxidants enhances sperm quality and functionality parameters. In addition, this supplementation improves in vivo/in vitro fertility outcomes, supporting the hypothesis that the beneficial effect observed upon sperm quality has a positive impact on reproduction outcomes.

Cryoprotective Effect of Pentoxifylline on Spermatogonial Stem Cell During Transplantation into Azoospermic Torsion Mouse Model

Preserving the spermatogonial stem cells (SSCs) in long periods of time during the treatment of male infertility using stem cell banking systems and transplantation is an important issue. Therefore, this study was conducted to develop an optimal cryopreservation protocol for SSCs using 10 mM pentoxifylline (PTX) as an antioxidant in basal freezing medium. Testicular torsion-a mouse model for long-term infertility-was used to transplant fresh SSCs (n = 6), fresh SSCs treated with PTX (n = 6), cryopreserved SSCs with basal freezing medium (n = 6), and cryopreserved SSCs treated with PTX (n = 6). Eight weeks after germ cell transplantation, samples were assessed for proliferation, through evaluation of Ddx4 and Id4 markers, and differentiation via evaluation of C-Kit and Sycp3, Tnp1, Tnp2, and Prm1 markers. According to morphological and flow cytometry results, SSCs are able to form colonies and express Gfra1, Id4, α6-integrin, and β1-integrin markers. We found positive influence from PTX on proliferative and differentiative markers in SSCs transplanted to azoospermic mice. In the recipient testis, donor SSCs formed spermatogenic colonies and sperm. Respecting these data, adding pentoxifylline is a practical way to precisely cryopreserve germ cells enriched for SSCs in cryopreservation, and this procedure could become an efficient method to restore fertility in a clinical setup. However, more studies are needed to ensure its safety in the long term.

Structure-based redesigning of pentoxifylline analogs against selective phosphodiesterases to modulate sperm functional competence for assisted reproductive technologies

Phosphodiesterase (PDE) inhibitors, such as pentoxifylline (PTX), are used as pharmacological agents to enhance sperm motility in assisted reproductive technology (ART), mainly to aid the selection of viable sperm in asthenozoospermic ejaculates and testicular spermatozoa, prior to intracytoplasmic sperm injection (ICSI). However, PTX is reported to induce premature acrosome reaction (AR) and, exert toxic effects on oocyte function and early embryo development. Additionally, in vitro binding studies as well as computational binding free energy (ΔG_bind) suggest that PTX exhibits weak binding to sperm PDEs, indicating room for improvement. Aiming to reduce the adverse effects and to enhance the sperm motility, we designed and studied PTX analogues. Using structure-guided in silico approach and by considering the physico-chemical properties of the binding pocket of the PDEs, designed analogues of PTX. In silico assessments indicated that PTX analogues bind more tightly to PDEs and form stable complexes. Particularly, ex vivo evaluation of sperm treated with one of the PTX analogues (PTXm-1), showed comparable beneficial effect at much lower concentration-slower AR, higher DNA integrity and extended longevity of  spermatozoa and  superior embryo quality. PTXm-1 is proposed to be a better pharmacological agent for ART than PTX for sperm function enhancement.

Specific phosphodiesterase type-10 inhibitor, papaverine, added after the cooling period improves canine sperm quality

The use of chilled semen has gained increasing interest in canine reproductive services. The addition of phosphodiesterase (PDE) inhibitors that increase the intracellular cyclic adenosine monophosphate levels may improve sperm motility. The purpose of this study was to examine the quality of sperm under the effect of the specific PDE-10 inhibitor (papaverine) added after storage for 1, 2, and 3 days at 5 °C. The ejaculates were obtained from 5 healthy Beagle dogs by digital manipulation. After collection, ejaculates were pooled, extended and cooled at 5 °C during 3 days. Sperm parameters were tested 30 min after the addition of different papaverine (PA) concentrations: 0, 5, 10 and 20 µM. Sperm motility (CASA), viability (PI/FITC-PNA) and capacitation status (chlortetracycline assay) were evaluated. The results showed that the addition of PA has no effect on sperm samples at day 0. However, concentrations of 5 and 10 µM increased (p < .05) sperm motility kinetics and viability significantly compared to the control at day 1, day 2 and day 3 of cooling. The addition of 20 μM PA decreased (p < .05) sperm quality parameters significantly and increased the percentage of capacitated/acrosome-reacted spermatozoa. In conclusion, the addition of 5 and 10 μM PA concentrations after cooled storage improved canine sperm quality.

Evaluation of pentoxifylline and Basal Medium Eagle supplemented to diluent on cryopreserved goat spermatozoa

This study investigated the effect of pentoxifylline (PTX) and Basal Medium Eagle (BME) on frozen-thawed goat spermatozoa. Immediately after initial examination of ejaculated semen, samples were pooled and reexamined for quality. Then, samples were divided into eight equal aliquots and diluted with a basic tris-extender containing PTX (3, 6, 9 mM) and BME (5 mM) to reach a final concentration of 25 × 10⁹ and frozen. After 24 hr, the samples were individually thawed at 37°C for 30 s and evaluated for different characteristics. Obtained post-thaw results from Computer-Assisted Sperm Analysis indicate using of 3 and 6 mM PTX led significantly to an improvement in total motility, progressive motility and velocity characteristics of spermatozoa, except the beat/cross frequency (BCF) which indicated statistically no differences (p > .05) among control and treatments. Diluents prepared with BME (5 mM) and PTX alone (3 and 6 mM) improved significantly the membrane integrity-functionality, acrosome integrity and also hyaluronidase activity. Regarding recovery rate, the results showed significantly (p < .05) higher values for diluents containing 3 and 6 mM PTX compared to other groups. Malondialdehyde concentration exhibited also a significant difference (p < .05) in diluents supplemented with 5 mM BME, 3, 6 and 9 mM PTX, and mixture of 3 mM PTX and 5 mM BME which illustrate a similarity for active mitochondria, apoptotic-like and dead spermatozoa. Finally, the ratio of sperm chromatin dispersion stained spermatozoa presented significant differences (p < .05) among treatments in which the diluents added PTX alone demonstrated significantly lower values than control and extenders containing the mixtures of BME and PTX. In conclusion, the observation in this study indicates using of 3 and 6 mM PTX and BME alone may improve significantly (p < .05) the quality of cryopreserved goat spermatozoa.

Effect of Caffeine and Pentoxifylline Added Before or After Cooling on Sperm Characteristics of Stallion Sperm

Different additives have been tested in cooled stallion sperm, in order to maintain sperm quality and to ameliorate the decrease in sperm fertility potential. In several species, caffeine and pentoxifylline promote sperm motility by increasing energy production. We evaluate the effects of caffeine and pentoxifylline when added to stallion sperm before or after cooling. Three ejaculates from five stallions each were processed and resuspended in skim milk extender. Caffeine (5 mM), pentoxifylline (3.5 mM), or both additives combined were included to sperm before or after cooling (4°C for 24 hours). Cooled sperm were incubated at 37°C and evaluated at 0, 30, 60, and 120 minutes for motility, morphology, viability (flow cytometry), and membrane functionality (hypo-osmotic swelling test). Results were analyzed by two-factor mixed model for repeated measures and Tukey comparisons. As main effects, the caffeine and pentoxifylline affected significantly motility and kinematic parameters, without interaction between treatment and incubation after cooling. No differences were observed whether the additives were added prior or after cooling. Pentoxifylline added after cooling reduced significantly motility during incubation, but with higher values at 30 minutes. We detected a decrease in morphologically normal sperm (P < .0001), caused by an increase of tail defects (P < .003) in the presence of both additives. Viability and membrane functionality were also significantly impaired by additives. Pentoxifylline when added after cooling improved sperm motility and kinematic parameters for a short period of time. However, sperm characteristic related to fertility potential was compromised after a prolonged exposure to caffeine or pentoxifylline.

Pentoxifylline effects on capacitation and fertility of stallion epididymal sperm

The aims of this study were to determinate whether pentoxifylline (PTX) increases the motion parameters of fresh and frozen-thawed equine epididymal spermatozoa, to evaluate the tyrosine phosphorylation of frozen-thawed epididymal sperm in the presence of PTX and to determine whether the PTX-treatment of stallion epididymal sperm prior to freezing improves the fertility response of mares to a reduced number of spermatozoa per insemination dose. Fifty epididymis were flushed with a skim milk based extender with or without PTX. The pre-treatment with PTX enhanced the sperm motility after being harvested (P<0.05); however the freeze-thaw process did not alter the sperm kinematics between control and treated samples (P>0.05). Plasma membrane integrity did not differ between control and PTX group after recovery and after thawing (P>0.05), as observed in tyrosine phosphorylation, which the PTX treatment did not alter the percentage of tail-associated immunofluorescence of cryopreserved epididymal sperm (P>0.05). For the fertility trial, different insemination groups were tested: 800×10⁶ epididymal sperm (C800); 100×10⁶ epididymal sperm (C100); 100×10⁶ epididymal sperm recovered in an extender containing PTX (PTX100). The conception rates for C800; C100 and PTX100 were 68.7% (11/16); 31.5% (5/16) and 50% (8/16), respectively. The conception rate did not differ among groups (P>0.05), however, a low number of animals was used in this study. A trend toward significance (P=0.07) was observed between C800 and C100 groups. In conclusion, PTX has no deleterious effect on sperm motility, viability and capacitation of cryopreserved stallion epididymal sperm. The conventional artificial insemination with 100×10⁶ sperm recovered with PTX ensures acceptable conception rates and maximize the limited number of doses of cryopreserved stallion epididymal sperm.

Evaluation of cholesterol- treated dromedary camel sperm function by heterologous IVF and AI

Cholesterol (cholesterol-loaded cyclodextrins: CLC) treatment of dromedary camel sperm prior to freezing enhances cryosurvival. The present study first validated the efficacy of a heterologous zona-free goat oocyte assay (n=115 oocytes) to evaluate camel sperm function in vitro (Experiment 1: n=6 bulls), then examined the effects of CLC treatment (1.5mg/mL CLC; CLC+) versus no treatment (0 CLC) of fresh (Experiment 2: n=4 bulls) and frozen-thawed (Experiment 3: n=5 bulls) camel sperm to penetrate, de-condense and form pro-nuclei in in vitro-matured goat oocytes. Finally, the ability of fresh 0 CLC and CLC+ sperm to fertilize in vivo was studied by artificially inseminating super-ovulated females (n=7-9 per treatment) and examining embryo production (Experiment 4: n=4-5 bulls/treatment). Camel spermatozoa penetrated (60%) and formed pro-nuclei (33%) in goat oocytes demonstrating the utility of this heterologous system for assessing sperm function in vitro. For fresh spermatozoa, 0 CLC-treated sperm performed better than their CLC+ counterparts for all parameters measured (P<0.05). In contrast, cryopreservation resulted in a sharp decline in sperm-oocyte interaction in 0 CLC aliquots but remained unaltered in CLC+ aliquots demonstrating a protective effect of cholesterol treatment. There was no difference between treatments in the in vitro fertilizing ability of frozen-thawed sperm or in the numbers of embryos retrieved following AI with fresh 0 CLC or CLC+ sperm. We conclude that although CLC treatment of dromedary camel sperm improves sperm motility it fails to confer an advantage to them in terms of improved in vitro sperm-oocyte interaction or in vivo fertilization under the conditions tested.

The battle of the sexes starts in the oviduct: modulation of oviductal transcriptome by X and Y-bearing spermatozoa

BACKGROUND

Sex allocation of offspring in mammals is usually considered as a matter of chance, being dependent on whether an X- or a Y-chromosome-bearing spermatozoon reaches the oocyte first. Here we investigated the alternative possibility, namely that the oviducts can recognise X- and Y- spermatozoa, and may thus be able to bias the offspring sex ratio.

RESULTS

By introducing X- or Y-sperm populations into the two separate oviducts of single female pigs using bilateral laparoscopic insemination we found that the spermatozoa did indeed elicit sex-specific transcriptomic responses. Microarray analysis revealed that 501 were consistently altered (P-value < 0.05) in the oviduct in the presence of Y-chromosome-bearing spermatozoa compared to the presence of X-chromosome-bearing spermatozoa. From these 501 transcripts, 271 transcripts (54.1%) were down-regulated and 230 transcripts (45.9%) were up-regulated when the Y- chromosome-bearing spermatozoa was present in the oviduct. Our data showed that local immune responses specific to each sperm type were elicited within the oviduct. In addition, either type of spermatozoa elicits sex-specific signal transduction signalling by oviductal cells.

CONCLUSIONS

Our data suggest that the oviduct functions as a biological sensor that screens the spermatozoon, and then responds by modifying the oviductal environment. We hypothesize that there might exist a gender biasing mechanism controlled by the female.

Supplementation of biotin to sperm preparation medium increases the motility and longevity in cryopreserved human spermatozoa

PURPOSE

To study the effect of supplementing biotin to sperm preparation medium on the motility of frozen-thawed spermatozoa.

METHODS

Semen samples of men attending the University infertility clinic (n = 105) were cryopreserved using glycerol-egg yolk-citrate buffered cryoprotective medium in liquid nitrogen. After a period of two weeks, the semen samples were thawed and the motile spermatozoa were extracted by swim-up technique using Earle's balanced salt solution (EBSS) medium supplemented with either biotin (10 nM) or pentoxifylline (1 mM). The post-wash motility was observed up to 4 h after incubation.

RESULTS

Both biotin and pentoxifylline supplementation resulted in significant increase in total motility (p < 0.05), progressive motility (p < 0.001) and rapid progressive motility (p < 0.05 v/s biotin and p < 0.01 v/s pentoxifylline) compared to the control at 1 h post-incubation period. Significantly higher percentage of total (p < 0.01, p < 0.05 in biotin and pentoxifylline respectively), progressive (p < 0.001) and rapid progressive motilities (p < 0.01) were observed in these two groups even at 2 h compared to the control. In the control group at 4 h after incubation, ~11% decline in total motility and ~8% decline in progressive motility was observed. However, in both biotin and pentoxifylline group the motility was significantly higher than control (p < 0.001). No significant difference in the motility was observed between biotin and pentoxifylline groups at any of the time intervals studied.

CONCLUSIONS

Biotin can enhance the sperm motility and prolong the survival of frozen-thawed semen samples which may have potential benefit in assisted reproductive technology field.