Effects of dexamethasone treatment (to mimic stress) and Vitamin E oral supplementation on the spermiogram and on seminal plasma spontaneous lipid peroxidation and antioxidant enzyme activities in dogs

Protective role of vitamin E against acrylamide-induced testicular toxicity from pregnancy to adulthood: insights into oxidative stress and aromatase regulation

Acrylamide (ACR) is a toxic chemical frequently encountered in daily life, posing health risks. This study aimed to elucidate the molecular-level mechanism of ACR's toxic effects on testicles and investigate whether Vitamin E can mitigate these effects. A total of 40 adult pregnant rats were utilized, divided into four groups: Control, ACR, Vitamin E, and ACR + Vitamin E. ACR and Vitamin E were administered to the mother rats during pregnancy and lactation, and to the male offspring until the 8th week post-birth. Serum hormone levels, oxidant-antioxidant parameters, histopathological examination of testicular tissue, and mRNA and protein levels of the testicular and liver aromatase gene were analyzed. Spermiogram analysis was conducted on the collected sperm samples from the male offspring. The results revealed that ACR exposure adversely affected hormone levels, oxidant-antioxidant parameters, histological findings, as well as aromatase gene and protein expressions. However, Vitamin E administration effectively prevented the toxic effects of ACR. These findings demonstrate that ACR application significantly impairs the reproductive performance of male offspring rats by increasing liver aromatase activity.

Effect of different concentrations of Trolox® in association with docosahexaenoic acid on equine semen freezing

The aim of this study was to evaluate the association of different concentrations of Trolox^® and the addition of a fixed concentration of DHA in the freezing of semen of Mangalarga Marchador stallions. To that end, 16 ejaculates were frozen in the following extenders: E1) BotuCrio^® (BC; Control); E2) BC + 50 ngml^-1 DHA + 30 µM Trolox^® (BCDHA30T); E3) BC + 50 ngml^-1 DHA + 40 µM Trolox^® (BCDHA40T); E4) BC + 50 ngml^-1 DHA + 50 µM Trolox^® (BCDHA50T). All the tested extenders were similar in preserving different kinematic parameters, cell functional integrity, compacted DNA, and high and intermediate mitochondrial activity (P>0.05). However, sperm cryopreserved in BCDHA40T showed higher velocities than sperm frozen in the control extender (P<0.05). The 30 µM concentration of Trolox^® was worse for sperm motility and the 50 µM concentration of Trolox^® did not adequately preserve the structural integrity of the membranes in an extender containing DHA when compared to the BotuCrio^® (P<0.05) extender. The use of Trolox^® in freezing extenders containing DHA did not maximize the effect of BotuCrio^®, except for in the case of sperm velocity parameters when at a concentration of 40 µM.

Responses of sperm mitochondria functionality in animals to thermal stress: The mitigating effects of dietary natural antioxidants

The reproductive consequences of global warming representing heat stress (HS) have been widely received more attention in the last decades. HS induced significant influence on the male reproductive cell, especially sperm functionally. Reduction in the sperm function induced by HS leads to failure of fertility potential. The main effects of HS on sperm are reducing sperm motility, increased abnormalities and changes in the fluidity of the membrane as well as cell morphology. Moreover, the destruction of mitochondrial function could be the result of adverse influences of HS. The protein contents and enzymes of mitochondria were lowered after the exposure of sperm to HS. Some natural antioxidants were used for improving sperm mitochondrial function under HS conditions. In this review, it was highlighted the potential influences of HS on sperm function through reduction in ATP Synthesis yield, mitochondrial activity, mitochondrial protein contents and mitochondrial enzymes, which involves the interference of mitochondrial remodelling in sperm of animals.

Effect of drugs on fertility in male dogs: A review

The aim of this literature review is to present and discuss the available data on the effects of drugs on male dog fertility. Apart from hormones and antihormonal agents, there is still only little information available regarding the effect of other drugs on sexual function and fertility in male dogs. A negative impact on fertility in male dogs has been reported for vincristine, cyclophosphamide, tetracycline and ketoconazole. However, preclinical safety studies of drugs for human use indicated that spermatogenesis in dogs may be sensitive to a wide variety of drugs. Thus, in cases of reduced fertility or infertility in male dogs, medical treatment should always be considered. In most cases, the effects of drugs on sexual function and spermatogenesis are reversible after the discontinuation of the drug. Further studies on the effects of drugs on male dog fertility are needed.

Protective Effects of N-Acetylcysteine on Lipopolysaccharide-Induced Respiratory Inflammation and Oxidative Stress

As the leading cause of bovine respiratory disease (BRD), bacterial pneumonia can result in tremendous losses in the herd farming industry worldwide. N-acetylcysteine (NAC), an acetylated precursor of the amino acid L-cysteine, has been reported to have anti-inflammatory and antioxidant properties. To explore the protective effect and underlying mechanisms of NAC in ALI, we investigated its role in lipopolysaccharide (LPS)-induced bovine embryo tracheal cells (EBTr) and mouse lung injury models. We found that NAC pretreatment attenuated LPS-induced inflammation in EBTr and mouse models. Moreover, LPS suppressed the expression of oxidative-related factors in EBTr and promoted gene expression and the secretion of inflammatory cytokines. Conversely, the pretreatment of NAC alleviated the secretion of inflammatory cytokines and decreased their mRNA levels, maintaining stable levels of antioxidative gene expression. In vivo, NAC helped LPS-induced inflammatory responses and lung injury in ALI mice. The relative protein concentration, total cells, and percentage of neutrophils in BALF; the level of secretion of IL-6, IL-8, TNF-α, and IL-1β; MPO activity; lung injury score; and the expression level of inflammatory-related genes were decreased significantly in the NAC group compared with the LPS group. NAC also ameliorated LPS-induced mRNA level changes in antioxidative genes. In conclusion, our findings suggest that NAC affects the inflammatory and oxidative response, alleviating LPS-induced EBTr inflammation and mouse lung injury, which offers a natural therapeutic strategy for BRD.

Effect of prolonged whole-body hyperthermia on adult male rat testes and the protective role of vitamin C and E: A histological and biochemical study

Hyperthermia (HT) is a significant risk factor for male infertility. Most researchers investigated the effect of localized and short-term HT on male fertility. This study aimed to assess the harmful impacts of prolonged and generalized HT on testicular histology and ultrastructure in rats. The possible protective effects of vitamin E (Vit E), Vit C, and their combination were also investigated. Thirty male adult Wister rats were used (5 groups). 1- control, 2- HT, 3- Vit C, 4- Vit E, and 5- Vit C + Vit E. Rats in groups 2-5 were subjected to HT (41°C), 1 hr daily for 2 weeks. HT-induced a significant decrease in body weight gain, food and water intake, and serum testosterone. HT showed a damaging effect on the testicular and coda epididymis tissue. HT significantly (p ≤ .05) produced oxidative stress (decreased serum catalase (145.49 ± 8.98), glutathione peroxidase (20.27 ± 4.46), superoxide dismutase (2.68 ± 0.54), and reduced glutathione (5.18 ± 0.33), and increased malondialdehyde (9.46 ± 1.55). Vit E alone and combined with Vit C, significantly protected the gonads against the deleterious effects of HT. The results recommended that prolonged HT of the whole body is harmful to male fertility. Prophylactic therapy with Vit E could help decrease the HT-induced male gonadal harm.

The effect of melatonin on testis histological changes and spermatogenesis indexes in mice following treatment with dexamethasone

Dexamethasone is a common medicine that is capable of causing malformation in the male reproductive system. The aim of this study was to investigate the effect of melatonin on testis histological changes and Spermatogenesis indexes in adult mice following treatment with dexamethasone. Adult male NMRI mice were divided randomly into four groups: control, dexamethasone (i.p injections, 7 mg/kg/day), dexamethasone + melatonin and melatonin (i.p injections, 20 mg/kg/day). After 7 days of treatment, the right testes were studied stereologically and the left testes were used to measure the daily sperm production (DSP). The serum levels of malondialdehyde (MDA), testosterone and total antioxidant capacity (TAC) were also measured. The left caudal epididymis was used to analyze sperm parameters. Data were analyzed using one way ANOVA and means were considered significantly different at p < 0.05. A significant decrease in the testis volume, seminiferous tubules volume, the number of spermatocytes, round and long spermatids, Spermatogenesis indexes, sperm parameters such as motility, count, viability, tail length and DSP, serum testosterone level, TAC and the body weight was found in the dexamethasone group compared to the control. Meanwhile a significant swelling of the interstitial tissue and a significant increase in the MDA level was found in the dexamethasone group compared to the control. The above parameters reached the control level in the dexamethasone + melatonin group. Melatonin can compensate for the adverse effects of dexamethasone on sperm parameters and the histology of the seminiferous tubules in mice.

Clinical and spermatological findings in male dogs with acquired infertility: A retrospective analysis

A variety of causative factors of infertility in male dogs has been reported. In this study, the results of clinical examination and semen evaluation of 61 infertile stud dogs are described. Infertility was defined as conception failure of at least three matings with different bitches. The dogs, belonged to various breeds, were 4-8 years old and had a history of prior normal fertility. The dogs were subjected to clinical examination including ultrasonography of the prostate and testes. The semen was evaluated using CASA and microscopically morphology and live-dead spermatozoa. In all dogs, the semen parameters were outside the reference range, and mostly oligoastheno-teratozoospermia was found. There were also three cases of azoospermia. Thirty dogs showed no clinical abnormalities of the genital organ and no signs of systemic diseases, and testicular degeneration was assumed as the possible cause of infertility. In 20 dogs, BPH was diagnosed. In three dogs, infertility was associated with hypothyroidism. Three dogs had a history of babesiosis, and one dog prolonged ketoconazole treatment. One case each of chronic prostatitis, prostatic adenocarcinoma, epididymitis and retrograde ejaculation was diagnosed. The cause of acquired infertility could not be identified in almost half of the dogs. In other, infertility was often associated with prostate diseases.

Low-dose heavy metal mixture (lead, cadmium and mercury)-induced testicular injury and protective effect of zinc and Costus afer in wistar albino rats

The study evaluated the protective effect of Costus afer on low-dose heavy metal mixture (LDHMM)-mediated effects in the testis of albino rats. The weight-matched animals were divided into six groups: normal control, metal mixture of (PbCl₂  + CdCl₂ + HgCl₂ ), combination of metal mixture + Costus afer at 750 mg/kg, combination of metal mixture + Costus afer at 1,500 mg/kg, combination of metal mixture + Costus afer at 2,250 mg/kg and combination of metal mixture + (ZnCl₂ ). LDHMM reduced (p < .05) the antioxidant biomarkers (superoxide dismutase, SOD; catalase, CAT; and glutathione, GSH) and increased (p < .05) the lipid peroxidation marker (malondialdehyde, MDA) and lead, cadmium and mercury concentrations in the testis. Treatment with LDHMM increased (p < .05) abnormal sperm morphology and plasma prolactin (PRL) level and decreased epididymal sperm count, viability, follicle-stimulating hormone (FSH), luteinising hormone (LH) and testosterone. LDHMM exposure caused deleterious changes in the testis. Treatment of rats with Costus afer (750, 1,500 and 2,250 mg/kg) dose-dependently reduced (p < .05) the LDHMM-mediated toxicity. Treatment with Costus afer also reversed the testicular weight and LDHMM decrease in antioxidant biomarkers. Costus afer may be a defensive modulator of LDHMM-mediated testicular lesions.

Canine spermatozoa-What do we know about their morphology and physiology? An overview

Spermatozoa are unique cells because of their morphological and physiological characteristics. They are produced during the process called spermatogenesis. Spermatogenesis consists of three phases: spermatocytogenesis, spermiogenesis and spermiation, during which spermatozoa undergo several changes. Spermatogenesis takes place within the seminiferous tubules containing two types of cells-the germ cells and the Sertoli cells-that alongside the Leydig cells, which play an important role when it comes to normal fertility. Everything is regulated by the hypothalamic-pituitary-gonadal axis and specific hormones due to multi-hormonal feedback systems. Spermatozoa possess morphological and physiological features, which are sometimes completely different from what is observed in various somatic cells. What is more, canine spermatozoa have specific characteristics making them special compared to the spermatozoa of other mammalian species. The metabolic energy production, which is crucial for the appropriate functioning of spermatozoa, can be fuelled by different metabolic pathways utilizing different chemical substrates. Inseparable from the oxidative phosphorylation process is the production of reactive oxygen species, which are both essential and toxic to spermatozoa. Furthermore, epididymis is a very important structure, responsible for the transport and maturation of spermatozoa, which are then stored in the last segment of epididymis-the epididymal cauda. Moreover, the retrieval of spermatozoa from the epididymides is crucial for the development of assisted reproduction techniques and sperm cryopreservation methods. The information gained from the research on domestic dogs might be transferred to their wild relatives, especially those species categorized as endangered.

The changes in semen quality, arginase activity and nitric oxide level in dexamethasone-treated rams

This study was made to investigate the effects of intramuscular administrations of dexamethasone on seminal plasma nitric oxide levels and arginase activity, and some spermatological parameters in rams. Ten Akkaraman rams weighing 50-60 kg and 2 years old were used as material in this study. The study was performed during the breeding season (September-November) for rams. The semen was collected by artificial vagina at 1st, 4th, 24th, 48th, 72nd and 96th hours for control group before dexamethasone administration. For treatment group, 0.25 mg/kg dexamethasone was administered and semen was collected at the time points described for control group. Spermatological characteristics of semen samples (semen volume, pH, sperm motility, density and abnormal sperm rate), seminal plasma arginase enzyme activities and nitric oxide levels were determined. It was determined that the administration of dexamethasone was detected to decrease seminal plasma arginase activity (p < .05 and .01) and nitric oxide level (p < .05), semen volume (p < .05 and .01), mass activity (p < .05 and .01), sperm density (p < .05) and sperm motility (p < .05 and .01), and to increase abnormal sperm rate (p < .05 and .01). In conclusion, dexamethasone is not recommended to be used during the breeding season as it damages the sperm quality of the rams.

Individual male dependent improvement in post-thaw dromedary camel sperm quality after addition of catalase

Cryopreservation is stressful to sperm cells inducing an increase in the production of reactive oxygen species and subsequently reducing post-thaw sperm quality. With the present study, there was evaluation of the protective effects of two antioxidants, epigallocatechin (1 mM) and catalase (500 IU/ml), added at thawing, as well as inter-individual variation on quality of cryopreserved dromedary camel spermatozoa. Semen was collected from six males and sperm, selected using single layer centrifugation, were cryopreserved. Post-thaw sperm quality was evaluated by assessing motility variables, viability and acrosome integrity then sperm were co-incubated with or without antioxidant (control) and further assessed at 1.5 and 3 h of the incubation period. Oxidative damage was measured colorimetrically for malondialdehyde production at 3 h of the incubation period. With the use of epigallocatechin there were not promising results, however, with use of catalase there were greater total and progressive motility, and values for some kinematic variables (P<0.05) at both incubation time points, although there were some differences among males. There was no overall effect of antioxidant based on production of malonaldehyde. The capacity of thawed sperm to fertilize, with and without addition of catalase at thawing, was studied using artificial insemination (n = 10 per treatment) with no differences between treatments (10% for both). It is concluded that catalase supplementations to semen extender prolong sperm survival, however, there is no improvement of in vivo fertilization as a result of this supplementation. There was an obvious male effect, necessitating further studies to understand the mechanisms of action of catalase.

Improvement of Sperm Motility Within One Month Under Selenium and Vitamin E Supplementation in Four Infertile Dogs with Low Selenium Status

Introduction

Significant improvement of sperm motility within one month effected by oral supplementation of selenium and vitamin E was described in four infertile male dogs which failed to conceive in their last three matings with different bitches.

Material and Methods

The dogs (a Golden Retriever, an English Cocker Spaniel, and two Tibetan Mastiffs) were supplemented daily with selenium (Se) (0.6 mg/kg organic Se yeast) and vitamin E (vit. E) (5 mg/kg) per os for 60 days. Semen was collected on days 0, 30, 60, and 90. The sperm concentration and motility parameters were evaluated by the CASA system, sperm morphology was explored by Diff-Quick staining, and live and dead spermatozoa were differentiated by eosin/nigrosin staining. The concentrations of Se and vit. E were measured in peripheral blood serum on semen collection days.

Results

Before administration, the concentrations of Se in blood plasma were low (86.0–165.0 μg/L). After 30 days of treatment there was an observable improvement in total and progressive sperm motility and kinematic parameters (VAP, VSK, VCL, ALH, BCF, and RAPID). The percentages of live and normal morphology sperm cells were also higher. There was also an observable increase in Se and vitamin E concentrations in blood serum. Bitches were successfully mated and delivered four to six puppies.

Conclusion

Supplementation with Se and vit. E improved rapid sperm motility and restored fertility in infertile dogs with low Se status.

Vitamin C ameliorates the adverse effects of dexamethasone on sperm motility, testosterone level, and spermatogenesis indexes in mice

BACKGROUND:

Dexamethasone (DEX) is a common medicine that is capable of causing malformation in the male reproductive system. The aim of this study was to investigate the effect of vitamin C (Vit-C) on spermatogenesis indexes and daily sperm production (DSP) in adult mice treated with DEX.

METHODS:

Male Naval Medical Research Institute (NMRI) mice were divided into four groups: Control, DEX (7 mg/kg/day), Vit-C (100 mg/kg/day), and DEX +Vit-C and treated for 7 days with intraperitoneal injection.

RESULTS:

A significant increase in the mean levels of serum and tissue malondialdehyde (MDA) and apoptosis of Leydig cells was found in the DEX group compared to the control group. Sperm motility, DSP, tubular differentiation index, meiotic index, spermatogenesis index, the mean number of spermatocytes, round and long spermatids, and Leydig cells, and also serum testosterone level decreased in the DEX group compared to the control group. The results of this study indicate that Vit-C can significantly prevent the adverse effects of DEX on the mean number of spermatocyte, spermatid, and Leydig cells, tubular differentiation, meiotic and spermatogenesis index, DSP, sperm motility, and the mean levels of serum MDA.

CONCLUSION:

In conclusion, our results showed that coadministration of Vit-C and DEX prevents the adverse effects of DEX on the spermatogenesis indexes and DSP.

Cat epididymal semen cryopreserved with and without vitamin E: effect on sperm parameters and lipid peroxidation

The aims of this study were to investigate: 1) if the addition of α-tocopherol (vitamin E) in three concentrations (0.3, 0.6 and 0.9 mM) is able to preserve spermatozoa integrity after thawing and 2) the effect of α-tocopherol supplementation on lipid peroxidation. Fifty four domestic cats were used in this study constituting 18 pools (3 cats per pool). Each pool was submitted at four experimental groups: group 0 (control) – epididymal sperm were frozen with a commercial Botucrio^® extender; group 0.3, group 0.6 and group 0.9 – the extender was supplemented with 0.3, 0.6 and 0.9 mM of α-tocopherol, respectively. Each semen sample was evaluated for motility, progressive forward motility, morphology, sperm viability (plasma membrane integrity-PMI), hypo-osmotic swelling test (HOST), before and after thawing. The evaluation of lipid peroxidation reaction by Thiobarbituric Acid Reactive Substances (TBARS) test was performed on thawed semen only. Results demonstrated that there was no significant difference between control and the three α-tocopherol groups with regards to motility and progressive motility after thawing (P > 0.05). As expected, in fresh samples viability was significantly higher than in all the cryopreserved groups in which there was no positive influence of any of the α-tocopherol concentration used. Lipid peroxidation was higher in the supplemented groups 0.6 and 0.9 mM of α-tocopherol than in control and in 0.3 mM group. In conclusion, the addition of α-tocopherol to the commercial extender had no positive influence on reduction of lipid peroxidation. This topic deserves further investigations to better understand the effect of cryopreservation procedures on epididymal spermatozoa and to establish adequate strategies to counteract sperm cryodamages.

Total antioxidant capacity and protein peroxidation intensity in seminal plasma of infertile and fertile dogs

The aim of this study was to evaluate the total antioxidant capacity and protein peroxidation intensity in seminal plasma of infertile and fertile dogs. The study was conducted on 10 infertile and 10 fertile dogs of various breeds. Infertility was defined as conception failure at least three matings with different bitches. Semen was collected by manual manipulation. The sperm concentration and motility parameters were evaluated using CASA Hamilton Thorne, Vers. IVOS 12.3. The morphology of spermatozoa and the percentage of live and dead sperm cells were assessed microscopically, total antioxidant capacity and the content of SH-groups in seminal plasma were determined spectrophotometrically, the contents of protein peroxidation markers in seminal plasma, bityrosine and formylokinurenine, were determined using spectrofluorimetric methods. Sperm concentration and total sperm count were significantly (p < 0.05) lower in infertile dogs than in fertile dogs (99.92 ± 3 0.05 × 10⁶ /ml vs. 282.07 ± 48.27 × 10⁶ /ml; 214.19 ± 114.74 × 10⁶ vs. 747.57 ± 210.94 × 10⁶ , respectively). The percentage of spermatozoa with normal morphology and the most determined motility parameters differed significantly (p < 0.05) between both groups. The mean values of total antioxidant capacity in the seminal plasma were significantly (p < 0.05) lower (19.95 ± 20.94 vs. 25.66 ± 23.18 µmol/g protein), whereas the mean contents of bityrosine and formylokinurenine in seminal plasma were significantly (p < 0.05) higher in infertile dogs than in fertile dogs (3.71 ± 4.83 µg/mg protein vs. 1.55 ± 2.00 µg/mg protein and 0.37 ± 0.45 µg/mg protein vs. 0.14 ± 0.08 µg/mg protein, respectively). In conclusion, the obtained results suggest that the poor semen quality and infertility in dogs could be associated with lowered total antioxidant capacity and increased protein peroxidation in seminal plasma as a consequence of oxidative stress.

The Electrical Stimulation of the Bed Nucleus of the Stria Terminalis Causes Oxidative Stress in Skeletal Muscle of Rats

Recent studies indicate that activation of hypothalamus-pituitary-adrenocortical axis (HPA) plays the crucial role in stress response, while several lines of evidence mark the bed nucleus of the stria terminalis (BST) as a major mediator of the HPA axis responses to stress. The purpose of this study was to investigate the influence of the corticosterone flux induced by the electrical stimulation of BST on markers of free radical damage of lipids and proteins and antioxidant enzyme activity in skeletal muscle of rats. The male Wistar rats were used and assigned to one of three groups: sham-operated (SHM; n = 6), two-week (ST2; n = 6), and four-week stimulated (ST4; n = 5) groups. Blood, soleus, and extensor digitorum longus muscles were collected. The chronic, 4-week electrical stimulation of the BST evokes increased plasma corticosterone concentration, which resulted in oxidative stress in skeletal muscles. We found higher level of lipid peroxidation markers, lower level of protein oxidation marker, and elevated antioxidant enzyme activity in both muscles. Our findings have also potential implication showing that reaction to the long-term “psychological stress” may lead to free radical damage of muscle.

Selenium and vitamin E supplementation enhances the antioxidant status of spermatozoa and improves semen quality in male dogs with lowered fertility

Studies showed a beneficial effect of supplementation with selenium (Se) and vitamin E on semen quality. The aim of the study was to investigate the effect of Se and vitamin E supplementation on the antioxidant status of spermatozoa and semen quality in dogs with lowered fertility. Ten dogs were supplemented daily with Se (6 μg/kg organic Se yeast) and vitamin E (5 mg/kg) per os for 60 days. Control group consisted of 10 males without the supplementation. Semen was collected on day 0, 30, 60 and 90. Sperm quality parameters were evaluated using CASA and a microscope. Concentrations of Se and vitamin E in blood as well as glutathione peroxidase (GSH-Px) activity and total antioxidant capacity (TAC) in the spermatozoa were determined. After 60 days of supplementation the concentration of spermatozoa, the majority of motility indicators and the percentage of normal morphology and live spermatozoa increased significantly (p < .05). An increase (p < .05) in concentration of Se and vitamin E in blood and GSH-Px-activity and TAC in the spermatozoa was detected. The study results indicate that Se and vitamin E supplementation for 60 days enhances the antioxidant status of spermatozoa and improves the quality of the semen in dogs with lowered fertility.

Effect of Vitamin E and Polyunsaturated Fatty Acids on Cryopreserved Sperm Quality in Bos taurus Bulls Under Testicular Heat Stress

Taurine bulls are highly susceptible to heat stress, leading to increased oxidative stress (OS) and impaired sperm viability. Polyunsaturated fatty acids (PUFAs) supplementation can be an alternative to improve semen quality, which also results in more sperm susceptibility to lipid peroxidation. Moreover, this deleterious effect can be exacerbated in animals affected by heat stress. Vitamin E is a key antioxidant that counteracts lipid peroxidation of sperm membrane caused by OS. Thus, combining PUFAs with vitamin E may improve sperm quality. In this context, this study aimed to evaluate the effect of interaction between PUFAs and vitamin E on sperm quality in Bos taurus bulls under testicular heat stress. Sixteen taurine bulls under testicular heat stress were randomly assigned in four groups: Control, Vitamin E, PUFA, and PUFA + Vitamin E. All groups lasted for 60 days. Samples were cryopreserved/thawed and analyzed for motility variables (CASA), membrane and acrosome integrity, mitochondrial activity, susceptibility to oxidative stress, DNA integrity, and sperm-binding capacity. Results showed that vitamin E had a beneficial effect on some sperm characteristics, whereas PUFA supplementation had an adverse effect when the two treatments were evaluated separately. Finally, the association between PUFAs and vitamin E did not improve sperm quality.

Immunosuppressants and Male Reproduction

Prolonged use of immunosuppressant medications is occasionally seen in infertile men with chronic inflammatory conditions; autoimmune disorders; or an organ or hematopoietic stem cell transplant. Chronic inflammation impacts negatively on male reproductive endpoints, so immunosuppressant therapy can produce improvements. Corticosteroids have been used to treat antisperm antibodies and even as an empirical treatment for male infertility in general. Trials of these methods have provided mixed results on semen quality and fertility, with improvement, no change and negative effects reported by different investigators. In a substantial number of observational studies, patients on long-term therapy with prednisone for chronic inflammatory disease, testosterone levels were lower compared to untreated controls, though randomized controlled trials have not been conducted. Similarly decreases in testosterone have been reported in men receiving corticosteroids to minimize transplant rejection; however, most were treated with multiple immunosuppressive medications that may have contributed to this effect. A large number of trials of healthy men treated with corticosteroids have shown some disruption in reproductive hormone levels, but other studies reported no effect. Studies in monkeys, rats (at human equivalent dose), cattle, sheep, and horses have shown endocrine disruption, including low testosterone with dexamethasone treatment. Of the cytostatic immunosuppressives, which have high potential for cellular damage, cyclophosphamide has received the most attention, sometimes lowering sperm counts significantly. Methotrexate may decrease sperm numbers in humans and has significant negative impacts in rodents. Other chemotherapeutic drugs used as immunosuppressants are likely to impact negatively on male fertility endpoints, but few data have been collected. The TNF-α Inhibitors have also received little experimental attention. There is some evidence that the immunophilin modulators: cyclosporine, sirolimus, and everolimus cause endocrine disruption and semen quality impairment. As we review in this chapter, results in experimental species are concerning, and well-designed studies are lacking for the effects of these medications on reproductive endpoints in men.

Características seminais e de membrana espermática em touros suplementados com tocoferol

RESUMO O trabalho teve como objetivo avaliar a integridade da membrana plasmática e qualidade seminal de touros suplementados com tocoferol. Foram utilizados 16 touros com idade média de 24 meses e peso médio de 462,2kg, em dois tratamentos: grupo controle (GC) e grupo suplementado com tocoferol (GE- 400 UI de tocoferol/ animal/dia) adicionados ao suplemento concentrado. Os grupos foram mantidos em pastejo com suplementação de 4,5kg/ animal/ dia de concentrado. A suplementação com tocoferol foi fornecida por 60 dias. Foram realizadas 4 coletas de sêmen, sendo: nos dias 0, 30, 60 e 15 dias após o término da suplementação. O sêmen foi coletado por eletroejaculação, aferiu-se as características físicas e morfológicas. Para avaliar a integridade de membrana utilizou-se o teste hiposmótico, coloração eosina/ nigrosina, coloração Pope e trypan blue. Os dados foram analisados através da ANOVA e do teste SNK com um nível de significância de 5%. Foi encontrado efeito da suplementação para vigor (p=0,0183) (GC=2,71±0,095 e GE=2,23±0,16). Não foram encontradas diferenças (p>0,05) para as demais variáveis: volume, motilidade, concentração, morfologia, integridade acrossomal, viabilidade espermática e integridade de membrana. Com os resultados obtidos, nas condições experimentais do presente trabalho, conclui-se que a suplementação oral com tocoferol de 400UI/dia não apresenta melhoria sobre a qualidade seminal nem a integridade da membrana espermática de touros.

Vitamin C and vitamin E supplementation alleviates oxidative stress induced by dexamethasone and improves fertility of breeder roosters

This study was conducted to determine the effect of supplemental dietary vitamin C (VC) and vitamin E (VE) on improving semen quality and antioxidative status in breeder roosters challenged with dexamethasone (DEX). 120 45-week-old Lveyang black-boned breeder roosters were divided into 5 experimental treatments, including negative group, positive group, and three trial groups, which were fed basal diet supplemented with 300mg/kg VC, 200mg/kg VE, or 300mg/kg VC and 200mg/kg VE (VC+VE). At 49 weeks of age, the positive control and trial groups were subcutaneously injected 3 times every other day with DEX 4 mg/kg body weight, the negative control group was sham injected with saline. At 50 weeks of age, average daily feed intake of birds challenged with DEX significantly increased (P<0.05), however, serum testosterone significantly decreased (P<0.05). Dietary supplementation of VC+VE enhanced serum testosterone and sperm motility remarkably (P<0.05). There were no differences in sperm viability between the DEX-treated groups. During the post-stress recovery period (52 weeks of age), dietary supplementation of VE and VC+VE significantly increased the body weight of birds under oxidative stress (P<0.01). VC, VE, and VC+VE groups had greater sperm viability than control group (P<0.01). Additionally, there was a decrease in the semen plasma malondialdehyde content (P<0.05) of the VC and VC+VE groups, and in the testicular malondialdehyde content (P<0.01) of the VE and VC+VE groups. In summary, VC, VE, especially their combination alleviate the oxidative stress induced by DEX and are favorable for the fertility of breeder roosters.

Effects of α-tocopherol and freezing rates on the quality and heterologous in vitro fertilization capacity of stallion sperm after cryopreservation

The effects of supplementation of α-tocopherol and different freezing rates (FRs) on the ability of stallion sperm to fertilize bovine oocytes with intact zona pellucida were investigated, in an attempt to develop a model to assess cryopreserved sperm function. Semen was obtained from four purebred Lusitano stallions (n = 4). Each ejaculate was subjected to cryopreservation with a commercial extender (Ghent, Minitub Iberia, Spain), without any supplementation (control) or supplemented with 2-mM α-tocopherol. The semen was exposed to two different FRs between 5 °C and -15 °C: slow (5 °C/min) and moderate (10 °C/min). After thawing, the viability (SYBR®-14 and propidium iodide [PI]), mitochondrial membrane potential (JC-1, 5,5',6,6'-tetrachloro-1,1',3,3'tetraethylbenzimidazolyl carbocyanine iodine) and membrane lipid peroxidation (C11-BODIPY(581/591)) of each sample were determined by flow cytometry. Moreover, the heterologous IVF rate was measured to evaluate the fertilization capacity of postthaw semen in the four different treatments. For both extenders, the viability was higher for spermatozoa cooled slowly (39.40 ± 2.17 vs. 17.59 ± 2.25-control; 31.96 ± 2.19 vs. 11.46 ± 1.34-Tocopherol; P < 0.05). The α-tocopherol extender improved (P < 0.05) postthaw lipid peroxidation (10.28 ± 0.70 vs. 15.40 ± 0.95-slow FR; 10.14 ± 0.40 vs. 13.48 ± 0.34-moderate FR); however, it did not improve viability and mitochondrial membrane potential. Regarding the IVF rate, in the moderate FR, α-tocopherol supplementation reported a higher percentage of IVF (20.50 ± 2.11; P < 0.05), comparing with the control (14.00 ± 1.84). Regarding the slow FR, no significance differences were observed for percentage of IVF between the two extenders and the FRs. However, it seems that the α-tocopherol supplementation improved the IVF rate. In conclusion, this research reported that bovine oocytes intact zona pellucida can be used to evaluate the quality of postthaw stallion semen and α-tocopherol supplementation in the stallion freezing extender might exert a protective effect against oxidative damage during heterologous IVF.

A meta-analysis of glucocorticoids as modulators of oxidative stress in vertebrates

Prolonged high secretion of glucocorticoids normally reflects a state of chronic stress, which has been associated with an increase in disease susceptibility and reduction in Darwinian fitness. Here, we hypothesize that an increase in oxidative stress accounts for the detrimental effects of prolonged high secretion of glucocorticoids. We performed a meta-analysis on studies where physiological stress was induced by administration of glucocorticoids to evaluate the magnitude of their effects on oxidative stress. Glucocorticoids have a significant effect on oxidative stress (Pearson r = 0.552), although this effect depends on the duration of treatment, and is larger in long-term experiments. Importantly, there was a significant effect on tissue, with brain and heart being the most and the least susceptible to GC-induced oxidative stress, respectively. Furthermore, effect size was larger (1) in studies using both sexes compared to males only, (2) when corticosterone rather than dexamethasone was administered and (3) in juveniles than in adults. These effects were not confounded by species, biochemical biomarker, or whether wild or laboratory animals were studied. In conclusion, our meta-analysis suggests that GC-induced oxidative stress could be a further mechanism underlying increases in disease susceptibility and decreases in Darwinian fitness observed under chronic stress.

Effect of antioxidant supplementation in semen extenders on semen quality and reactive oxygen species of chilled canine spermatozoa

The objective of this study was to evaluate quality of chilled dog semen processed with extenders containing various antioxidants. Single ejaculates from five dogs were always pooled and evaluated for concentration, sperm motility, progressive motility (RSF-movement), viability, acrosomal integrity and by the hypo-osmotic swelling (HOS)-test. Also, superoxide (O(2)(-)) production, hydroxyl radicals (OH) and total reactive oxygen species (tROS) were determined. Pooled semen was divided in seven aliquots (for control and test conditions), which were diluted to a final concentration of 67x10(6)spermatozoa/ml with TRIS-glucose-egg yolk extender with or without the following supplements: control (without antioxidants), vitamin C (0.5mM), N-acetyl-l-cysteine (NAC; 0.5mM), taurine (0.2mM), catalase (100u/ml), vitamin E (0.1mM) and 5-(4-dimethylamino-phenyl)-2-phenyl-penta-2,4-dienoic acid (B16; 0.1mM). The semen aliquots were chilled and preserved at 4 degrees C. Portions of chilled semen were removed at 24 and 72h, and semen quality was evaluated after rewarming. At 24h the mean (+/-S.E.M.) sperm motility was higher (p<0.001) when vitamin E, taurine and B16 were added in the extender, whereas more spermatozoa with RSF-movement were observed (p<0.001) in the vitamin E, catalase, B16 and taurine groups. Sperm viability was higher (p=0.040) in B16 and vitamin E groups and the percentage of swollen spermatozoa was higher (p=0.002) only in the B16 group. Acrosomal integrity and OH were not significantly influenced by any of the antioxidants tested. Superoxide production was significantly lower when vitamin C, B16 and vitamin E were added in semen extenders compared with the control (p=0.017). All antioxidant groups, except vitamin C and NAC, contained less tROS compared to the control group, but only the B16 group value differed significantly (p=0.05). At 72h sperm motility was higher (p<0.001) when vitamin E, catalase, B16, taurine and NAC were added in the extender. More spermatozoa with RSF-movement were observed (p<0.001) in the vitamin E, catalase, B16, taurine and NAC treatment groups. Sperm viability was higher (p=0.001) when vitamin E, B16, taurine and vitamin C were added in semen extenders. HOS-test percentages were higher (p=0.016) in the B16, vitamin E, catalase and NAC groups. Acrosomal integrity was not influenced in any case. Production of O(2)(-) was significantly higher using catalase compared to all the other groups (p=0.006), while OH was not significantly influenced by any of the antioxidants tested. The addition of vitamin E, catalase and B16 in semen extenders resulted in significantly lower tROS values compared with the controls (p<0.0005). The results suggest that vitamin E and B16 had the most pronounced effect in preserving semen quality of chilled dog spermatozoa.

Effect of antioxidant supplementation on semen quality and reactive oxygen species of frozen-thawed canine spermatozoa

The objective of this study was to evaluate post-thaw quality of frozen dog semen processed with diluents containing different antioxidants. Ejaculates were collected, pooled and evaluated for concentration, motility, rapid steady forward movement (RSF movement), viability, acrosomal integrity and by the hypo-osmotic swelling test. Also, superoxide production, hydroxyl radicals and total reactive oxygen species (tROS) were determined. The pool was divided in seven aliquots, for control and test conditions, which were processed for cryopreservation. The sperm pellets were diluted to a final concentration of 200x10(6)sperm/ml with TRIS-glucose-egg yolk extender containing one of the following supplements: vitamin C (1.5mM), NAC (N-acetyl-l-cysteine; 1.5mM), taurine (0.6mM), catalase (300U/ml), vitamin E (0.3mM) and B16 [5-(4-dimethylamino-phenyl)-2-phenyl-penta-2,4-dienoic acid; 0.3mM]. Post-thaw semen evaluation showed that mean (+/-S.E.M.) motility was increased (p<0.001) after addition of catalase (49.75+/-3.63 versus 39.00+/-2.90 in controls), whereas more spermatozoa with RSF movement were observed (p<0.001) after the catalase, NAC and vitamin E treatments (31.75+/-3.46, 28.00+/-3.27, 26.75+/-3.15, respectively, versus 17.00+/-2.26 in controls). Viability was increased (p<0.001) after addition of catalase, taurine, NAC and tocopherol (66.00+/-3.03, 61.90+/-2.48, 60.60+/-1.93 and 60.50+/-4.12, respectively, versus 51.70+/-2.81 in controls). The percentage of swollen spermatozoa was increased after addition of catalase and taurine (61.75+/-1.61 and 61.25+/-1.49, respectively, versus 55.65+/-1.64 in controls). Acrosomal integrity was not influenced in any case. B16 addition had adverse effects on all parameters evaluated. None of the reactive oxygen species were significantly reduced post-thaw in antioxidant treated semen. The results suggest that catalase had the most pronounced effect in improving post-thaw quality of canine spermatozoa.