Supplemental effect of varying L-cysteine concentrations on the quality of cryopreserved boar semen

Cryopreservation is associated with the production of reactive oxygen species, which leads to lipid peroxidation of the sperm membrane and consequently a reduction in sperm motility and decreased fertility potential. The aim of this study was to determine the optimal concentration of L-cysteine needed for cryopreservation of boar semen. Twelve boars provided semen of proven motility and morphology for this study. The semen was divided into four portions in which the lactose-egg yolk （LEY） extender used to resuspend the centrifuged sperm pellet was supplemented with various concentrations of L-cysteine to reach 0 mmol L^-1 （group Ⅰ, control）, 5 mmol L^-1 （group Ⅱ）, 10 mmol L^-1 （group Ⅲ） and 15 mmol L^-1 （group Ⅳ）. Semen suspensions were loaded in straws （0.5 mL） and placed in a controlled-rate freezer. After cryopreservation, frozen semen samples were thawed and investigated for progressive motility, viability using SYBR-14/EthD-1 staining and acrosome integrity using FITC-PNA/EthD-1 staining. There was a significantly higher （P 〈 0.01） percentage of progressive motility, viability and acrosomal integrity in two L-cysteine-supplemented groups （group Ⅱ and group Ⅲ） compared with the control. There was a biphasic effect of L-cysteine, with the highest percentage of progressive motility, viability and acrosomal integrity in group Ⅲ. In conclusion, 5 or 10 mmol L^-1 was the optimum concentration of L-cysteine to be added to the LEY extender for improving the quality of frozen-thawed boar semen.     

富含DHA的鸡蛋黄和L-半胱氨酸盐酸盐添加物对冷冻猪精液质量的影响

本文旨在研究富含DHA的鸡蛋黄和L-半胱氨酸添加物对冷冻猪精液质量的影响。从5只皮特兰猪种获得15个射精样本，根据冷冻添加物的组成将其分为4组：正常鸡蛋黄组（组1），富含DHA的鸡蛋黄组（组2），添加了5mmol／L半胱氨酸添加物的正常鸡蛋黄（组3），添加了5mmol／L的半胱氨酸添加物的富含DHA的鸡蛋黄（组4）。精液冷冻保存过后在50℃下解冻12秒。之后检测精子直线前进运动，精子生存力，顶体完整性，解冻精液中精子质膜的功能完整性。只添加IL-半胱氨酸（组3）可以提高精子直线前进运动（P〈0．05），与富含DHA的鸡蛋黄一起添加（组4）既能增加直线前进运动（P〈0．05）又能改善顶体完整性（P〈0．01）。富含DHA的鸡蛋黄单独添加对解冻后精液的质量没有任何作用（P〉0．05）。总之，抗氧化的三．半胱氨酸单独或者与富含DHA的鸡蛋黄一起作用可以明显改善解冻后精液质量，尤其是直线前进运动力和顶体完整性。     

Fennel (Foeniculum vulgare) provides antioxidant protection for boar semen cryopreservation

Boar semen is extremely vulnerable to cold shock and it is also sensitive to peroxidation due to the high content of unsaturated fatty acids in the plasma membrane. Antioxidants exert a protective effect on the plasma membrane of frozen boar sperm. Fennel has been shown to contain antioxidant substances. Therefore, this study was performed to evaluate the effect of different concentrations of fennel added to the freezing extender on boar semen quality and lipid peroxidation after thawing. Semen collected from four boars was cryopreserved in lactose-egg-yolk extender or in the same extender with varying concentration of fennel essences: low (LF); medium (MF); high (HF). Analysis of data clearly indicated that higher concentrations of fennel produced significant improvement in total motility. Moreover, when fennel was included in the extender, a dose-dependent tendency to increase sperm viability was observed. In contrast, the addition of fennel had no effect on acrosome integrity or hypoosmotic swelling test (HOST) compared with the control. Malondialdehyde (MDA) formation decreased significantly in fennel groups, yielding similar results for MF and HF. Fennel seems a new antioxidant for use in sperm cryopreservation, but its particular effects on sperm physiology must be further studied, especially the causes of motility stimulation and its effect on lipoxidation.     

Spectrophotometric application of resazurin reduction assay to evaluate boar semen quality

The resazurin reduction assay depends on the ability of metabolically active cells to reduce the resazurin redox dye to resorufin. In the present study we applied and made a diagnostic evaluation of a spectrophotometric application of the resazurin reduction assay to assess the colour change of resazurin reduction in butanol extracted colour to evaluate boar semen quality. Forty-one samples of boar semen from various breeds were included in the study. The absorption peaks for resazurin and resorufin were found to be 610 and 575 nm, respectively. Absorbance at 610 nm, where the minimum overlap of the two peaks was observed, was used in further analysis. Spearman rank correlation analysis was used to determine the correlation between the resazurin reduction assay and various semen parameters. The highest correlations were observed with the concentration of motile spermatozoa (r = -0.841; p < 0.001), sperm concentration (r = -0.833; p < 0.001), sperm index (-0.826; p < 0.001) and concentration of viable spermatozoa (r = -0.763; p < 0.001). Sensitivity and specificity, at 94.1 and 91.7%, respectively, indicate that the present test is highly accurate in discriminating between the samples according to the sperm index. When motile sperm concentration was used to distinguish between good and poor samples, high sensitivity (93.6%) was also found, whereas the test was only moderately, 80%, specific. The stability of butanol extracts in terms of A610 at different times of measurement confirmed that the resazurin reduction could be spectrophotometrically measured within 7 days from the time of assay performance, making the assay much more useful. Based on these results, the assay could be used as an additional tool for evaluating the quality of boar semen.     

Organic selenium supplementation increases PHGPx but does not improve viability in chilled boar semen

This study evaluated the effects of dietary organic selenium (Se) on viability of chilled boar semen. Twelve boars were divided into three groups: control (CON), 0.3 mg kg^?1 sodium selenite; inorganic (INO), 0.5 mg kg^?1 sodium selenite and organic (ORG), 0.5 mg kg^?1 Se yeast. The experiment was conducted within 10 weeks, and analysis was performed fortnightly, in storage semen by 72 h. No effect was observed on motility; however, straightness and linearity percentages were higher (P < 0.05) in the animals receiving CON diet compared with INO group. Percentages of cells with both plasma and acrosomal intact membranes, lipidic membrane peroxidation and mitochondrial membrane potential were similar on all treatments. Animals receiving CON diet presented higher (P < 0.05) values of ATP when compared with INO group. The PHGPx was higher (P < 0.05) in animals that received ORG in comparison with INO group. In conclusion, organic selenium supplementation increases PHGPx but does not improve chilled semen viability in 72 h.     

Supplementing oregano essential oil to boar diet with strengthened fish oil: Effects on semen antioxidant status and semen quality parameters

Previous research has shown benefits of dietary fish oil supplementation on semen quality of boars. However, little is known about how antioxidant protects lipid peroxidation on spermatozoa from n‐3 polyunsaturated fatty acid (PUFA) addition. This study evaluated the effect of oregano essential oil (OEO) supplementation on semen antioxidant status and semen quality in boars fed a diet enriched with fish oil. Thirty‐four mature boars of proven fertility, received daily 2.5 kg basal diet top‐dressed with 45 g soybean oil and 15 g fish oil to meet the n‐3 PUFA requirement of spermatozoa, randomly allocated to one of four groups supplemented with 100 mg α‐tocopheryl acetate kg^?1 (control), or 250 or 500 or 750 mg OEO kg^?1 for 16 weeks. Semen was collected at weeks 0, 8, 12 and 16 for measurements of sperm production, motion characteristics, sperm α‐tocopherol content, antioxidant enzyme activities, reactive oxygen species (ROS), DNA damage (8‐hydroxydeoxyguanosine, 8‐OHdG), lipoperoxidation (malondialdehyde, MDA) and seminal total antioxidant capacity (TAC). Sperm production and motion characteristics were similar (p > .05) among groups throughout the experimental week 16, but increased (p < .01) with experimental week. Although higher α‐tocopherol content and superoxide dismutase (SOD) activities were in OEO group spermatozoa, feeding diet with 500 mg/kg OEO resulted in elevation in seminal TAC, decrease in sperm ROS, MDA and 8‐OHdG than control group (p < .05). Overall, these results support the view that oregano essential oil has a positive effect on antioxidant capacity in boar when used fish oil.     

Effect of storage in short--and long-term commercial semen extenders on the motility, plasma membrane and chromatin integrity of boar spermatozoa

For artificial insemination (AI) in pigs, preservation of liquid boar semen at 16-20 degrees C is still common practice as sperm cryopreservation remains suboptimal in this species. To meet the different needs of the swine industry, several extenders have been developed to preserve semen in liquid form for short--and long-term storage. In the present study, three different commercial extenders devised for short-term (BTS+) or long-term preservation (MR-A and X-Cell), were used to test whether storage of semen from four mature, fertile boars at 17 degrees C for 96 h would affect sperm characteristics relevant for fertility, such as motility, membrane integrity and chromatin stability. Computer-assisted sperm analysis, and stainings with the acylated membrane dye SYBR-14/propidium iodide, and acridine orange in connection with flow cytometry were used to evaluate these variables. Percentages of total motile spermatozoa decreased slightly, but significantly, after 72-96 h. While membrane integrity values varied during the period of study, no significant changes in either membrane integrity or chromatin stability were, however, registered. This suggests a customary 96-day storage at 17 degrees C in these extenders was too short an interval to cause losses of integrity in nuclear DNA in the boar population studied.     

Chlorogenic acid improves the quality of boar semen subjected to cooled storage at 15°C

The aim of this study was to investigate the effect of chlorogenic acid (ChA) in boar semen stored at 15°C. Twelve ejaculates were processed into insemination doses at different concentrations of ChA (0.0, 1.5, 3.0, 4.0 and 6.0 mg/ml) or vitamin E (200 μl/ml) as positive control. Semen was analysed after 0, 24 and 72 hr of storage. ChA improved (p < .05) sperm motility, acrosome integrity and mitochondrial activity in all periods of storage. Furthermore, after 24 hr of storage, ChA above 1.5 mg/ml supported the sperm viability until 120 min after reheating (p < .05). Both ChA and vitamin E were similarly efficient in increasing the antioxidant capacity of semen, reducing the malondialdehyde levels before and after 72 hr of storage (p < .05). However, with 72 hr of storage, ChA at 3.0 mg/ml improved the mitochondrial activity over vitamin E (p < .05). In conclusion, results suggest that the concentration of 3.2 mg/ml of ChA is the best for semen stored for up to 24 hr. However, for semen stored for a longer period, 6.0 mg/ml or more should be used.     

Effects of season on boar semen parameters and antioxidant enzymes in the south subtropical region in Brazil

Although boar semen productivity is affected by seasonality, its effects are not equal among different regions which raise concerns regarding the profitability of boar stud farms. Therefore, the goals of this study were (i) to evaluate the seasonal effect on semen production in a commercial boar stud farm located in a subtropical climate region and (ii) to verify whether the activities of superoxide dismutase and glutathione peroxidase in spermatozoa and seminal plasma were associated with seminal traits of fresh and cooled semen. Nine boars were collected twice per season, and routine seminal parameter analyses were performed together with superoxide dismutase and glutathione peroxidase activities in seminal plasma and spermatozoa. Despite a reduction in sperm concentration in spring and summer, most seminal parameters were constant year‐round. Temperature–humidity index was higher in the summer compared to spring, autumn and winter (p < .05). Superoxide dismutase activity in spermatozoa was increased in summer compared to autumn and winter (p < .05). The activities of both enzymes in seminal plasma and spermatozoa glutathione peroxidase remained unaltered throughout the seasons. In conclusion, seasonality showed little influence in overall boar seminal parameters despite microclimatic differences among seasons, and spermatozoa collected during summer increased superoxide dismutase activity.     

Effect of captopril on semen quality

Various studies (direct and indirect) have presented the effect of captopril, a universally used antihypertensive medication, on semen quality; yet, this effect is still collectively unreviewed. This review systematically discusses and summarises the effect of captopril on semen quality. We searched all published articles in the MEDLINE electronic database since June 1985 until January 2016 using the keywords “captopril” and “sperm,” and certain supporting articles were reviewed and considered, if relevant. In conclusion, up to the present time, captopril does not appear to induce a striking change in semen quality, and hence on male infertility, while it may affect the rate of spermatozoa–egg fusion as it inhibits the activity of angiotensin‐converting enzyme that is released during capacitation and the acrosome reaction. Further research, mainly clinical, is still desired to prove these effects.     

男性肿瘤患者精液冷冻保存后常规参数分析

目的:了解男性肿瘤患者精液质量现状,探索保存男性肿瘤患者生育能力的方法。方法:对来源于2005~2013年浙江省人类精子库43例肿瘤自精保存患者的精液质量进行回顾性分析,检测项目包括精液体积、精子浓度、精子活力、精子冷冻复苏率等指标。比较肿瘤患者与供精志愿者(248例)之间精液质量的差异;并将肿瘤患者分为睾丸肿瘤组(22例)和非睾丸肿瘤组(21例),比较两组之间精液质量的差异。结果:43例肿瘤患者精液的平均精子浓度(60.90×106/ml)、前向运动精子百分率(41.07%)及精子冷冻复苏率(49.98%)均显著低于供精志愿者(分别为74.27×106/ml、51.79%和57.33%),P均<0.05;睾丸肿瘤组的冻后平均前向运动精子百分率(15.68%)与冷冻复苏率(42.81%)均显著低于非睾丸肿瘤组(分别为28.36%和57.53%),P均<0.05。结论:肿瘤患者精液质量普遍下降,进行自精保存的时机非常重要,应该加强自精保存的宣传力度。另外,睾丸肿瘤患者精液冷冻保存效果较差,精子库应对其冷冻复苏率低下的原因进行深入研究,优化冷冻保存技术,为患者提供更好的生育力保护。     

Ultrastructure evaluation of goat spermatozoa after freezing in a skim milk‐based extender with Trolox supplementation

The aim of this work was to evaluate the in vitro effect of adding Trolox in freezing extender for goat semen. Ejaculates from five bucks were evaluated, and when approved, the samples were pooled, diluted according to experimental groups [Trolox 0 (control), 30, 60 and 120 nmol ml^?1] and frozen in an automated system. Thawed samples (37 °C/30 s) were evaluated for plasma membrane (PMi) and acrosome integrity (Aci), mitochondrial membrane potential (MMP) and sperm kinematics by CASA system. Spermatozoa ultrastructure was evaluated in fresh and post‐thawed semen. No significant difference (P > 0.05) was observed among control and Trolox groups in the analyses of PMi, Aci, MMP and CASA in goat spermatozoa after thawing. Samples of 60 and 120 nmol ml^?1 Trolox groups had a higher percentage of cells that had intact plasma membranes in spermatozoa head than in the other groups, although they did not differ (P > 0.05) before being frozen. A higher percentage (P < 0.05) of spermatozoa with intact mitochondria was observed in fresh semen, control and Trolox 60 nmol ml^?1 groups than in the other groups. Addition of Trolox to skim milk extender at 60 nmol ml^?1 ultrastructurally preserves the plasma membrane and mitochondrial sheath integrity in goat spermatozoa after cryopreservation.     

The effect of cancer on semen quality after cryopreservation of sperm

The results of cryopreservation of sperm from cancer patients were retrospectively reviewed in an effort to better understand the relationship between semen quality and the presence of different kinds of cancer. The semen analysis results for 146 patients referred to our infertility center for sperm banking over a 2-year period were examined. These patients were divided into three groups according to their diagnosis: group I, prevasectomy controls; group II, patients with lymphoma and Hodgkin's disease; and group III, patients with testicular cancer, e.g., seminoma, embryonal cell carcinoma, or teratocarcinoma. The seminal parameters assessed included sperm count and prefreeze and postthaw motility and velocity. For these parameters, significant decrease from control values (P less than 0.05 to P less than 0.01) was seen in groups II and III. The specimens from group I patients retained good motility and velocity after thawing. Our results indicate that semen quality is adversely affected by the presence of cancer in the body.     

Effects of oncological treatments on semen quality in patients with testicular neoplasia or lymphoproliferative disorders

Pretherapy sperm cryopreservation in young men is currently included in good clinical practice guidelines for cancer patients. The aim of this paper is to outline the effects of different oncological treatments on semen quality in patients with testicular neoplasia or lymphoproliferative disorders, based on an 8-year experience of the Cryopreservation Centre of a large public hospital. Two hundred and sixty-one patients with testicular neoplasia and 219 patients with lymphoproliferative disorders who underwent chemotherapy and/or radiotherapy and pretherapy semen cryopreservation were evaluated. Sperm and hormonal parameters (follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, inhibin B levels) were assessed prior to and 6, 12, 18, 24 and 36 months after the end of cancer treatment. At the time of sperm collection, baseline FSH level and sperm concentration were impaired to a greater extent in patients with malignant testicular neoplasias than in patients with lymphoproliferative disorders. Toxic effects on spermatogenesis were still evident at 6 and 12 months after the end of cancer therapies, while an improvement of seminal parameters was observed after 18 months. In conclusion, an overall increase in sperm concentration was recorded about 18 months after the end of cancer treatments in the majority of patients, even if it was not possible to predict the evolution of each single case ‘a priori''. For this reason, pretherapy semen cryopreservation should be considered in all young cancer patients.     

Improvement in quality of cryopreserved human spermatozoa by swim-up before freezing

Selecting a population of spermatozoa by the swim-up technique yields, after freezing and thawing, a population of cells that contains proportionally more spermatozoa which are morphologically normal, fewer spermatozoa with damaged tail membranes, and a greater percentage of progressively motile spermatozoa with greater velocities and amplitudes of head displacement than those obtained after freezing and thawing the same semen samples in the normal way. This pattern was found for the semen from 10 patients and five volunteers. However, the cells selected by swim-up were as susceptible to the stresses caused by freezing and thawing as unselected spermatozoa in the original semen sample, and the improvement came from the better quality of the initial sample.     

Effect of statin on semen quality characteristics

Statins are lipid-lowering medications widely used to reduce the risk of cardiovascular diseases. Biochemically, they act by decreasing synthesis of cholesterol via inhibiting 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase. Since 1992, various research studies have investigated the effect of statins on semen quality characteristics; however, to date, there is no collective summary to such effect. Here, we have systematically discussed and abridged all research studies published in Scopus, PubMed and Web of Science databases that are directly linking statin to semen fertility characteristics using the keywords “statin” versus “sperm” and “semen”. In summary, considering the animal studies, statins, in general, were found to ameliorate semen quality characteristics in reproductive detrimental conditions, while, in human males or in in vivo systems with normal reproductive conditions, in general, statins showed negative to blunt effects against semen quality characteristics, mainly sperm motility. However, further research studies, in particular human studies, in this specific research setting is still needed to approve these effects.     

Effect of paracetamol on semen quality

Several published studies, both direct and indirect, have connected paracetamol, also named acetaminophen, a commonly used over‐the‐counter analgesic and antipyretic medication, with semen quality and male infertility, although as yet this connection is unclear. This review addresses the effect of paracetamol on semen quality and hence on male factor infertility. We searched the MEDLINE database from January 1980 through January 2017 for English‐language articles using the key words “paracetamol” and “acetaminophen” versus “sperm.” References from articles were used only if relevant. In summary, paracetamol, when used at high doses, appears to change semen quality, particularly sperm morphology, and hence its fertilising ability. Such effect of paracetamol on semen quality may occur by suppressing testosterone synthesis, inducing oxidative stress, provoking apoptosis of spermatocytes, reducing nitric oxide production and inhibiting prostaglandin synthesis. Further research, particularly clinical research, will be very important to confirm these effects.     

Effect of air-conditioner exposure on semen quality

Aim: To investigate the effect of air-conditioner exposure on semen quality. Methods: The data came from the healthy male volunteers, aged 22 to 30 years, who went to centers for maternity and children health for premarital physical examination in Shanghai,Henan, Zbejiang and Hebei from December 1998 to February 2000.     

Antioxidant effect of lemon balm (Melissa officinalis) and mate tea (Ilex paraguensys) on quality,lipid peroxidation and DNA oxidation of cryopreserved boar epididymal spermatozoa

In this study, we investigated the protective ability of the addition of two antioxidant herb extracts, mate tea and lemon balm, on boar epididymal frozen–thawed spermatozoa quality. Testes from mature boars were collected at local slaughterhouse, and sperm samples from epididymis were recovered by flushing. Spermatozoa were cryopreserved in lactose–egg yolk buffer supplemented with various concentrations of lemon balm and mate tea (0, 2.5, 5 and 10 g l^?1) using the straw‐freezing procedure. Motion parameters, acrosome and plasma membrane integrity, lipoperoxidation levels and DNA oxidative damage (8‐hydroxy‐2′‐deoxyguanosine base lesion) were evaluated. There were no differences among experimental groups with regard to motility characteristics, viability, acrosome and plasma membrane integrity; however, the highest concentration of lemon balm produced significant (P < 0.05) improvement in curvilinear trajectory, straightness and amplitude of lateral head displacement after thawing. The supplementation of freezing extender with mate tea and lemon balm reduced sperm lipid membrane peroxidation, and only mate tea protected DNA against oxidative damage during cryopreservation at 120 min post‐thawing (P < 0.05). Mate tea experimental extender at concentration of 10 g l^?1 showed the lowest percentage of sperm oxidised DNA and malondialdehyde generation; thus, mate tea is a potential candidate such as antioxidant compound on boar sperm cryopreservation medium.     

Effect of ibuprofen on semen quality

Ibuprofen is a widely used analgesic/antipyretic medication belongs to the nonsteroidal anti‐inflammatory class. Even though the influence of ibuprofen on semen quality has been investigated in various occasions, the comprehensive understanding and discussion of its impact on semen quality is still yet to be determined. In this work, we systematically review and reveal the effect of ibuprofen on semen quality, and thus on fertilising capability. To achieve this goal, we searched the main research databases (Scopus and PubMed) from 1 June 1986 through 13 October 2018 for English‐language articles and abstracts using the keywords “ibuprofen” versus “semen” and “sperm”. In addition, related published articles or abstracts were also discussed if relevant. Altogether, the main stream of research, from both in vitro and in vivo studies, presents an adverse effect of ibuprofen on different sperm parameters such as motility, viability, count and DNA integrity; however, such effect is not yet confirmed in humans. Mechanisms by which ibuprofen affects semen quality may be by reducing testosterone and prostaglandin synthesis, chelating zinc ions and inhibiting nitric oxide synthesis. However, further research studies, mainly clinical, are still of great importance to confirm the effects of ibuprofen on semen quality.