Effect of Honey, Coenzyme Q10, and ß-Carotene/α-Tocopherol as Novel Additives in Rabbit-Sperm Cryopreservation Extender.

The effectiveness of rabbit-sperm cryopreservation is still below average compared to other domestic species. After the sperm cryopreservation process, post-thawing parameters like motility and membrane integrity are significantly compromised. The use of new extender constituents is an approach that can be used to improve the effectiveness of cryopreservation. Accordingly, we used honey (1.25, 2.5, 5, and 10%), coenzyme Q10 (100 and 200 µM), and ß-carotene/α-tocopherol (500 µM/620 µM and 250 µM/310 µM) as candidate components for rabbit-sperm extenders during cryopreservation. Ejaculates from commercial adult rabbit bucks (n = 5) were cryopreserved using conventional freezing. Several post-thawing sperm parameters were assessed, including total motility, membrane integrity, viability, nuclear membrane integrity, acrosome reaction, and mitochondrial membrane potential and activation. Additionally, we performed hormonal analyses of the seminal plasma. Moreover, we analyzed the post-thawing levels of a molecular marker of sperm quality, proAKAP4, which was used in rabbits for the first time. Our findings showed that the 2.5% honey supplementation increased the post-thawing sperm motility (13.75 ± 3.75%) compared to the greater concentrations employed. However, the post-thawing motility was negatively affected by the coenzyme Q10 (0%, in both groups) but was not affected by the ß-carotene/α-tocopherol supplementation (22 ± 18.15%, and 11.67 ± 10.17%). In conclusion, the cryopreservation protocols of this study did not help to maintain the sperm parameters after thawing. Further studies are required to identify novel protocols to mitigate the damage caused to rabbit sperm during cryopreservation.

Mating modifies the expression of crucial oxidative-reductive transcripts in the pig oviductal sperm reservoir: is the female ensuring sperm survival?

Background: Mating induces large changes in the female genital tract, warranting female homeostasis and immune preparation for pregnancy, including the preservation of crucial oxidative status among its pathways. Being highly susceptible to oxidative stress, sperm survival and preserved function depend on the seminal plasma, a protection that is removed during sperm handling but also after mating when spermatozoa enter the oviduct. Therefore, it is pertinent to consider that the female sperm reservoir takes up this protection, providing a suitable environment for sperm viability. These aspects have not been explored despite the increasing strategies in modulating the female status through diet control and nutritional supplementation. Aims: To test the hypothesis that mating modifies the expression of crucial oxidative-reductive transcripts across the entire pig female genital tract (cervix to infundibulum) and, particularly in the sperm reservoir at the utero-tubal junction, before ovulation, a period dominated by estrogen stimulation of ovarian as well as of seminal origin. Methods: The differential expression of estrogen (ER) and progesterone (PR) receptors and of 59 oxidative-reductive transcripts were studied using a species-specific microarray platform, in specific segments of the peri-ovulatory sow reproductive tract in response to mating. Results: Mating induced changes along the entire tract, with a conspicuous downregulation of both ER and PR and an upregulation of superoxide dismutase 1 (SOD1), glutaredoxin (GLRX3), and peroxiredoxin 1 and 3 (PRDX1, PRDX3), among other NADH Dehydrogenase Ubiquinone Flavoproteins, in the distal uterus segment. These changes perhaps helped prevent oxidative stress in the area adjacent to the sperm reservoir at the utero-tubal junction. Concomitantly, there were a downregulation of catalase (CAT) and NADH dehydrogenase (ubiquinone) oxidoreductases 1 beta subcomplex, subunit 1 (NDUFB1) in the utero-tubal junction alongside an overall downregulation of CAT, SOD1, and PRDX3 in the ampullar and infundibulum segments. Conclusions: Natural mating is an inducer of changes in the expression of female genes commanding antioxidant enzymes relevant for sperm survival during sperm transport, under predominant estrogen influence through the bloodstream and semen. The findings could contribute to the design of new therapeutics for the female to improve oxidative-reductive balance.

Apoptosis and glucocorticoid-related genes mRNA expression is modulated by coenzyme Q10 supplementation during in vitro maturation and vitrification of bovine oocytes and cumulus cells.

Oocyte in vitro maturation (IVM) and vitrification procedures lead to detrimental effects on the overall oocyte quality. The addition of antioxidants during IVM, such as the coenzyme Q10 (Q10), has been demonstrated to positively impact on the cumulus-oocyte complexes due to its role in protection from oxidative damage and modulating gene transcription. Furthermore, glucocorticoids (GC) regulate gene transcription, energy metabolism and apoptosis during the early steps of reproduction. In this sense, most GC actions are mediated by the glucocorticoid receptor (NR3C1), a transcription factor. However, the specific roles of GC in ovarian physiology and oocyte maturation are still unknown. In this regard, a better knowledge on the expression of GC-related and apoptosis-related genes during IVM and cryopreservation procedures could potentially benefit the refinement of assisted reproductive techniques in the bovine species. The present study aims to explore the expression of NR3C1 mRNA in fresh and vitrified bovine oocytes and cumulus cells in response to Q10 (50 µM), and the effect of cortisol addition (0.25 µM, 0.5 µM) on the expression of NR3C1. We also studied the mRNA expression of NR3C1-related genes belonging to the GC regulation pathway, such as hydroxysteroid dehydrogenases (HSD11B1; HSD11B2), immunophilins (FKBP4; FKBP5), signal transducers and activators of transcription (STAT3; STAT5A), the mineralocorticoid receptor (NR3C2), and to the apoptosis pathway, such as the anti- (BCL2) and pro-apoptotic (BAX) mRNA transcripts in oocytes and cumulus cells 1) after IVM, and 2) after vitrification, both in presence or absence of Q10 supplementation during IVM. Our results show that there is an increase in the NR3C1 receptor expression after vitrification of oocytes, but not after exogenous cortisol supplementation during IVM. In addition, Q10 reduces the mRNA expression of HSD11B1 and FKBP5 in oocytes at levels of immature oocytes (HSD11B1 mRNA expression also in cumulus cells), and the BAX:BCL2 ratio mRNA expression. After vitrification in the presence of Q10, HSD11B2 mRNA expression increases in cumulus cells, while HSD11B1 and BAX:BCL2 mRNA expression decreases significantly both in oocytes and cumulus cells. In conclusion, our results show for the first time the effect of IVM, vitrification and Q10 supplementation on the mRNA relative expression of GC-related and apoptosis genes, and the effect of vitrification in the protein expression of NR3C1.

Effect of crocin and naringenin supplementation in cryopreservation medium on post-thaw rooster sperm quality and expression of apoptosis associated genes.

The aim of our study was to examine the effects of crocin (0.5 (C0.5), 1 (C1) and 1.5 (C1.5) mM) and naringenin (50 (N50), 100 (N100) and 150 (N150) µM) in cryopreservation extender for freezing rooster semen. Sperm motility, viability, abnormalities, membrane functionality, active mitochondria, apoptosis status, lipid peroxidation (LP), GPX, SOD, TAC, the mRNA expression of pro-apoptotic (CASPASE 3) and anti-apoptotic (Bcl-2) genes, fertile eggs, hatched eggs and hatching rate were investigated following freeze-thawing. C1 and N100 resulted in higher (P < 0.05) total motility and progressive motility in comparison to the control group. The C1 and N100 groups improved viability, membrane functionality and reduced lipid peroxidation. We found higher values for active mitochondria with C1 and N100 compared to control group. The C1 and N100 groups showed lower percentages of early apoptosis when compared with control group. Also, C1 and N100 had higher TAC, compared to the control group. The mRNA expressions of BCL-2 in the C1 and N100 groups were significantly higher than that of other treatments. The expression of CASPASES 3 was significantly reduced in C1 and N100 group (P < 0.05) when compared to control group. Significantly higher percentages of fertile eggs, hatched eggs and hatching rate were observed in C1 and N100 compared to the control group. In conclusion, crocin at 1 mM and naringenin at 100 µM seem to improve the post-thawing rooster semen quality, fertility and could protect the sperm by reducing the pro-apoptotic (CASPASE 3) and increasing anti-apoptotic (Bcl-2) genes.

In vitro assessment of egg yolk-, soya bean lecithin- and liposome-based extenders for cryopreservation of dairy bull semen.

The study was conducted to compare the effect of four commercially available extenders (Triladyl®- egg yolk-based; Andromed® and Bioxcell®-plant based and Optixcell®-liposome-based) on post-thaw sperm quality and functionality variables evaluated using computer-assisted sperm analysis and flow cytometry. A total of 30 ejaculates from five bulls were analysed. With use of Triladyl®, sperm had a greater post-thaw total motility than with use of Bioxell® and Optixcell® but there was no difference as compared with use of Andromed® with the greatest (P < 0.05) percentage of progressively motile cells. With use of Optixcell®, there was a greater (P < 0.05) percentage of sperm with an intact membrane than with use of Triladyl® and Bioxcell®, but values were similar with use of Andromed®. Acrosome damage in semen preserved with use of Optixcell® was less than with use of Bioxcell® and Andromed®. With use of Optixcell®, there was a greater percentage of viable spermatozoa with a lesser lipid disruption (P < 0.05) when compared with the other extenders. Production of peroxides was greater for sperm cryopreserved with use of Triladyl® and Optixcell® while less superoxide was produced in the samples cryopreserved with the egg yolk-based extender. Optixcell® appears to be a promising alternative to replace traditional egg yolk extenders. With use of Optixcell®, however, there were greater peroxide concentrations after thawing. With use of Andromed®, there were similar results as with use of Optixcell®, therefore, it could be an effective substitute for egg-yolk based media due to the greater proportion of highly and progressively motile spermatozoa at thawing.

Effect of Achillea millefolium-loaded nanophytosome in the post-thawing sperm quality and oxidative status of rooster semen.

The aim of this study was to compare the effectiveness of antioxidants including Achillea millefolium extract (AmE) (n0t1.5: 1.5, n0t3: 3 and n0t4.5: 4.5 mg/L) and AmE loaded in nano phytosome (n1t1.5: 1.5, n1t3: 3 and n1t4.5: 4.5 mg/L) in the freezing of Ross 308 rooster semen. Sperm motility (CASA), membrane integrity (HOS test), viability, total abnormality and enzymatic parameters (SOD, CAT and GPx) were assessed after thawing. AmE-loaded nano phytosome at a concentration of 3 mg/l resulted in significantly (P < 0.05) higher total motility (MOT) (73.78 ±â€¯2.92) and at concentrations of 1.5 mg/L and 3 mg/L in progressive motility (PROG) (14.12 ±â€¯0.38, 16.78 ±â€¯0.38) in comparison with the control group (MOT: 58.48 ±â€¯2.92; PROG: 9.08 ±â€¯0.38). Sperm viability (Vi) was higher (P < 0.05) in n1t3 (74.62 ±â€¯1.55) and membrane integrity (Mi) in n0t3 and n1t3 groups (65.91 ±â€¯1.91, 63.73 ±â€¯1.91, respectively) compared to the control groups (Vi: 66.85 ±â€¯1.55; Mi: 53.18 ±â€¯1.91). Moreover, the lowest percentage of MDA was measured in n1t3 group (1.31 ±â€¯0.31). There was no significant difference for SOD and CAT values with the use of various extenders. In conclusion, we suggest that AmE loaded in nano phytosome at 3 mg/l dose can be added to basic extender for improving rooster sperm motility, viability and oxidative stress values during the freezing procedure.

Ethylene glycol, but not DMSO, could replace glycerol inclusion in soybean lecithin-based extenders in ram sperm cryopreservation.

The aim of this study was to evaluate the effects of glycerol, ethylene glycol or DMSO in a soybean lecithin extender for freezing ram semen. In this study, 20 ejaculates were collected from four Ghezel rams and diluted with soybean lecithin extender with glycerol (7%), ethylene glycol (3%, 5% and 7%) or DMSO (3%, 5% and 7%). Sperm motility (CASA), membrane integrity (HOS test), viability, total abnormality, mitochondrial activity (Rhodamine 123) and apoptotic features (Annexin V/Propidium iodide) were assessed after thawing. There was no significant difference between glycerol and ethylene glycol at different concentrations (3% and 5%) regarding sperm total and progressive motility, viability, and membrane integrity. The least percentages of mitochondrial functionality were observed in samples frozen with all different DMSO concentrations tested (P<0.05). Moreover, the percentage of post-thawed dead sperm was the greatest for all the DMSO concentrations compared with other groups (P<0.05). Thus, DMSO had an adverse effect on the post thaw ram sperm parameters. In contrast, ethylene glycol could be a desirable substitute of glycerol in the freezing extender, in view of similar results obtained in post-thaw quality of ram semen cryopreserved in a soybean lecithin extender. We propose that glycerol in a soybean lecithin based extender could be replaced by ethylene glycol at 3% or 5% concentrations.

Post-thawing quality and incubation resilience of cryopreserved ram spermatozoa are affected by antioxidant supplementation and choice of extender.

The performance of cryopreserved semen in ovine artificial insemination still needs improvement. Some antioxidants have been tested, with variable success. We cryopreserved semen from Churra rams using TES-Tris-fructose with 4% glycerol and 10% egg yolk (EY) or 3.5% soybean lecithin (SL), with 1 mM of reduced glutathione (GSH), Trolox, crocin, or cysteamine. Samples were analyzed after thawing and incubation (6 hours, 38 °C) for motility (computer-assisted sperm analysis [CASA]), viability, acrosomal integrity, apoptosis, mitochondrial activity, chromatin status, and lipoperoxidation (malondialdehyde production). Interactions (antioxidant/extender/incubation) were significant for most variables. Extenders yielded similar results, although SL depressed mitochondrial activity and linearity (P < 0.001), it improved motility (P < 0.05), DNA fragmentation (P < 0.05), and acrosomal damage (P < 0.001). The control, GSH, and Trolox showed greater viability with SL (P < 0.01). Cysteamine depressed motility (0 hours: 51.6 ± 2.0% vs. 32.3 ± 4.3%; 6 hours: no motility vs. 32.5 ± 1.9%; P < 0.001), but improved viability when using EY (P = 0.004). Crocin increased acrosomal damage (P = 0.022) but improved linearity-related parameters after thawing (P = 0.014). Trolox considerably reduced malondialdehyde production in both extenders (8.6 ± 0.4 nmol per 10(8) cells vs. 14.2 ± 0.3 in EY and 20 ± 0.6 in SL; P < 0.001). Interestingly, thiol antioxidants (cysteamine and GSH) increased DNA fragmentation (percentage of DNA fragmentation index), whereas crocin reduced it (P < 0.05). Interactions between extender and antioxidant must be taken into account for improving sperm cryopreservation. Soybean lecithin seems to be a suitable replacement for EY, but its effect on mitochondria must be investigated. Trolox and crocin might be useful for ram semen freezing.

Refrigerated storage of ram sperm in presence of Trolox and GSH antioxidants: effect of temperature, extender and storage time.

Antioxidants have a potential to improve the quality and fertility of refrigerated-stored ram semen. Reduced glutathione (GSH) and Trolox (0.2, 1 and 5mM) were evaluated in ram semen preserved at 15 and 5°C up to 48 and 96h, respectively. Extenders were also evaluated (15°C: Tris-citrate-fructose, TCF, without lipids, and TES-Tris-fructose 10% egg yolk, TTF-EY; 5°C: TTF-EY and 3.5% soybean lecithin, TTF-SL; INRA96 at both temperatures). Storage at 5°C resulted in poorer quality than 15°C up to 48h, while allowing acceptable quality at 96h. Antioxidants had few effects on sperm quality, with use of Trolox resulting in reduced motility and viability in TCF. Storage at 15°C in the TCF extender resulted in decreased motility, viability and mitochondrial activity compared with use of TTF-EY. Sperm quality when storage was at 5°C was similar, but storage in TTF-SL resulted in decreased motility and mitochondrial activity. Acrosomal status was only slightly affected by extender and antioxidant. Mitochondrial activity was improved by antioxidants in TTF-SL, and GSH at 5mM when semen was stored at 5°C in TTF-EY. A preliminary artificial insemination trial indicated that supplementation with GSH has the potential for improving lambing (P<0.1). In conclusion, use of antioxidants resulted in lesser effects than extender composition or storage time on quality of ram semen. Use of Trolox negatively impacted sperm quality and GSH had some positive impacts. The use of soybean lecithin requires further research to assess its impact on mitochondria.

Reduced glutathione and Trolox (vitamin E) as extender supplements in cryopreservation of red deer epididymal spermatozoa.

The use of assisted reproductive techniques in cervids is increasing as the commercial use of these species increase. We have tested the suitability of the antioxidants Trolox and reduced glutathione (GSH) for freezing red deer epididymal spermatozoa, aiming at improving post-thawing quality. Samples from 19 stags were frozen in a TES-Tris-fructose extender (20% egg yolk, 8% glycerol), with 1 or 5 mM of antioxidant. Motility (CASA), lipoperoxidation (malondialdehyde -MDA- production), membrane status, mitochondrial activity, acrosomal status (flow cytometry) and chromatin status (SCSA: %DFI and %HDS; flow cytometry) were assessed after thawing and after 6 h at 39°C. There were few differences between treatments after thawing, with Trolox reducing MDA production in a dose-response manner. After the incubation, sperm quality decreased and %DFI increased moderately, with no change for MDA. GSH improved motility, kinematic parameters and mitochondrial status, with a slight increase in %HDS. GSH 5 mM also increased moderately MDA production and %DFI, possibly due to enhanced metabolic activity and reducing power. Trolox maintained MDA low, but was detrimental to sperm quality. Trolox might not be appropriate for the cryopreservation of red deer epididymal spermatozoa, at least at the millimolar range. GSH results are promising, especially regarding motility improvement after the post-thawing incubation, and should be selected for future fertility trials.