In vitro exposure of porcine sperm to functionalized superparamagnetic nanoparticles

Nanotechnology and its applications have advanced significantly in recent decades, contributing to various fields, including reproduction. This study introduces a novel method to label porcine oocytes with nanoparticles (NPs) bound to oviductin (OVGP1, Ov) for use in Assisted Reproductive Technologies (ARTs). Despite promising developments, concerns about NP toxicity in gametes necessitate thorough investigation. This research aims to assess the impact of functionalized NPs (NPOv) on sperm functionality. Boar sperm were co-incubated with NPOv for 0, 0.5 and 1 h in two media: BTS (semen dilution and conservation) and TALP (sperm capacitation and in vitro fertilization-IVF). Sperm quality parameters (viability, motility and kinematics) showed no significant differences in TALP medium (p > .05). In BTS, although some kinetic parameters were altered, motility, progressive motility and viability remained unaffected (p > .05). Additionally, NPs presence on the zona pellucida (ZP) of oocytes did not affect sperm attachment (p > .05). In conclusion, in vitro exposure of boar sperm to OVGP1-functionalized NPs in IVF medium or attached to the ZP surface of matured oocytes does not impair sperm functionality, including their binding ability to the ZP.

Exploring the full potential of sperm function with nanotechnology tools

Sperm quality is essential to guarantee the success of assisted reproduction. However, selecting high-quality sperm and maintaining it during (cryo)preservation for high efficiency remains challenging in livestock reproduction. A comprehensive understanding of sperm biology allows for better assessment of sperm quality, which could replace conventional sperm analyses used today to predict fertility with low accuracy. Omics approaches have revealed numerous biomarkers associated with various sperm phenotypic traits such as quality, survival during storage, freezability, and fertility. At the same time, nanotechnology is emerging as a new biotechnology with high potential for use in preparing sperm intended to improve reproduction in livestock. The unique physicochemical properties of nanoparticles make them exciting tools for targeting (e.g., sperm damage and sexing) and non-targeting bioapplications. Recent advances in sperm biology have led to the discovery of numerous biomarkers, making it possible to target specific subpopulations of spermatozoa within the ejaculate. In this review, we explore potential biomarkers associated with sperm phenotypes and highlight the benefits of combining these biomarkers with nanoparticles to further improve sperm preparation and technology.

Comparison of Nanoparticles and Single-Layer Centrifugation for Separation of Dead from Live Stallion Spermatozoa

The goal of this study was to compare the efficacy of coated iron-core nanoparticles and single-layer centrifugation for separation of dead from live stallion spermatozoa. Our hypothesis was that nanoparticles would bind to dead sperm and allow for separation from live sperm using a magnet, resulting in a population of spermatozoa with a high percentage of total and progressive motility. Treatment Group 1 was an untreated control. Treatment Group 2 (nanoparticles, NP) utilized sperm incubated with nanoparticles followed by application of a magnet to remove dead sperm adhered to the coated nanoparticles. Treatment Group 3 (single-layer centrifugation, SLC) layered sperm above EquiPure™ followed by centrifugation. Semen samples were subsequently evaluated for sperm motility parameters, plasma membrane integrity, acrosome status, and morphology. The SLC technique yielded higher (p < 0.05) progressive motility (76 ± 9.2%) than the NP separation technique (59 ± 12.2%) or the untreated control (47.3 ± 5.1%). However, the total number of sperm recovered was higher (p < 0.05) in the NP technique (526.2 ± 96.6 × 106) than the SLC procedure (211.7 ± 70 × 106), yielding a higher total number of progressively motile sperm (317.6 ± 109 × 106) recovered using the NP technique than the SLC technique (157.8 ± 43.6 × 106). The percentage of live, acrosome intact sperm recovered was higher for SLC than NP. In summary, the SLC technique yielded a higher percentage of sperm motility, intact plasma membranes, and acrosome integrity, but yielded lower total sperm than with the nanoparticle separation technique.

Biomarker-based human and animal sperm phenotyping: the good, the bad and the ugly†

Conventional, brightfield-microscopic semen analysis provides important baseline information about sperm quality of an individual; however, it falls short of identifying subtle subcellular and molecular defects in cohorts of "bad," defective human and animal spermatozoa with seemingly normal phenotypes. To bridge this gap, it is desirable to increase the precision of andrological evaluation in humans and livestock animals by pursuing advanced biomarker-based imaging methods. This review, spiced up with occasional classic movie references but seriously scholastic at the same time, focuses mainly on the biomarkers of altered male germ cell proteostasis resulting in post-testicular carryovers of proteins associated with ubiquitin-proteasome system. Also addressed are sperm redox homeostasis, epididymal sperm maturation, sperm-seminal plasma interactions, and sperm surface glycosylation. Zinc ion homeostasis-associated biomarkers and sperm-borne components, including the elements of neurodegenerative pathways such as Huntington and Alzheimer disease, are discussed. Such spectrum of biomarkers, imaged by highly specific vital fluorescent molecular probes, lectins, and antibodies, reveals both obvious and subtle defects of sperm chromatin, deoxyribonucleic acid, and accessory structures of the sperm head and tail. Introduction of next-generation image-based flow cytometry into research and clinical andrology will soon enable the incorporation of machine and deep learning algorithms with the end point of developing simple, label-free methods for clinical diagnostics and high-throughput phenotyping of spermatozoa in humans and economically important livestock animals.

State-of-the-art and future perspectives in infertility diagnosis: Conventional versus nanotechnology-based assays

According to the latest World Health Organization statistics, around 50 to 80 million people worldwide suffer from infertility, amongst which male factors are responsible for around 20 to 30 % of all infertility cases while 50 % were attributed to the female ones. As it is becoming a recurrent health problem worldwide, clinicians require more accurate methods for the improvement of both diagnosis and treatment schemes. By emphasizing the potential use of innovative methods for the rapid identification of the infertility causes, this review presents the news from this dynamic domain and highlights the benefits brought by emerging research fields. A systematic description of the standard techniques used in clinical protocols for diagnosing infertility in both genders is firstly provided, followed by the presentation of more accurate and comprehensive nanotechnology-related analysis methods such as nanoscopic-resolution imaging, biosensing approaches and assays that employ nanomaterials in their design. Consequently, the implementation of nanotechnology related tools in clinical practice, as recently demonstrated in the selection of spermatozoa, the detection of key proteins in the fertilization process or the testing of DNA integrity or the evaluation of oocyte quality, might confer excellent advantages both for improving the assessment of infertility, and for the success of the fertilization process.

Equine Spermatozoa Selection by Magnetic Activation for Use in Assisted Reproduction

This study aimed to select high-quality spermatozoa by sperm separation by magnetic activation of the fresh equine semen, compared to density gradient centrifugation and evaluating cell quality after selection. The semen of 10 stallions was collected by the artificial vagina technique. The samples analyzed were: (1) fresh semen; (2) density gradient centrifugation (DGC); (3) separation by magnetic activation (MASS) (nonapoptotic portion NAP); (4) separation by MASS (apoptotic portion-APT). Was analyzed: motility (light microscopy), concentration (Neubauer chamber), semen morphology (humid chamber in phase contrast), and supravital test (eosin/nigrosine). In DGC, 20 × 10⁶ spermatozoa were used in the gradient of Percoll at 90% and 45% (400 μL each), centrifugation at 900 G/5 min, the pellet was diluted in HEPES. In MASS, 10 × 10⁶ spermatozoa were diluted in 1.5 mL of HEPES, centrifugation at 300 G/10 min, pellet was resuspended in 150 μL of HEPES with 20 μL of nanoparticles bound to annexin V, incubation for 15 minutes and filtered in the magnetic separation column. The nonapoptotic fraction was collected directly and the apoptotic fraction after removal the column from the magnet and adding 300 μL of HEPES. The total abnormalities were 43.2% ± 2.78%, with the DGC and MASS being effective in reducing sperm abnormality by 15.6% ± 2.10% and 24.30% ± 1.63%, respectively, like the observed for the number of cells with intact membranes (50% lower in the APT portion). This nanotechnological method is efficient in producing high-quality semen samples for assisted reproduction procedures.

Application of conventional metallic nanoparticles on male reproductive system - challenges and countermeasures

The application of nanotechnology in the present era has substantial impact on different industrial and medical fields. However, the advancement in nanotechnology for potential therapeutic and consumer benefits has been an anxious cause regarding the probable hazardous consequences of these molecules in biological systems and the environment. The toxic effects can perturb the physiologic system broadly and reproductive function and fertility specifically. Despite engineered nanomaterials (ENMs) having a wide range of applications, toxicological investigations of the probable ramifications of ENMs on the reproductive systems of mammals and fertility remains in its nascence. Complication in the male reproductive system is quite a pertinent issue in today's world which comprises of benign prostatic enlargement, prostate cancer, and unhealthy sperm production. The therapeutic drugs should not only be active in minimum dose but also site-specific in action, criteria being met by nanomedicines. Nanomedicine therapy is promising but encompasses the chances of adverse effects of being cytotoxic and generating oxidative stress. These hurdles can be overcome by creating coated nanoparticles with organic substances, modification of shape and size, and synthesizing biocompatible green nanoparticles. This review attempts to look into the applications of most widely used metals like zinc, titanium, silver, and gold nanoparticles in the therapy of the male reproductive system, their prospective harmful effects, and the way out to create a safe therapeutic system by specific modifications of these metal and metal oxide nanoparticles.

Nano-depletion of morbid spermatozoa up-regulate Ca2+ channel, depolarization of membrane potential and fertility in buffalo

Despite recent advances in technique of spermatozoa cryopreservation, there are still ejaculates present that fail to meet strict quality standard; mainly due to detrimental effect of imbalance of free radicals. The omnipresence of dead/defective spermatozoa in ejaculates of eutherian species is a major source of excessive free radicals. Though sperm-selection techniques, as well as addition of antioxidants addressed the problem to a certain extent, the major source of free radicals in the semen remained, causing much damage. This study attempts to remove dead/damaged spermatozoa using negative fertility-marker. The effect is unraveled by Hypo-osmotic (HOS), and fluorescein-conjugated Pisum sativum agglutinin (FITC-PSA) assay, further confirmed by Ca²⁺-regulating mechanisms and depolarization of sperm membrane potential, reduction in concentration of free radicals and finally by in vitro fertility assay. The study involved functionalization of iron oxide nanoparticles (IONPs) with silane followed by bio-conjugation with anti-ubiquitin antibodies. The nano-purification of semen using anti-ubiquitin conjugated iron oxide nanoparticles (IONPs) (antibody concentrations 0.5, 1.0 and 2.0 μg/ml) was attempted. The efficiency of nano-purification was 18.1%-43.8% in the study. The results revealed greater (P ≤ 0.05) spermatozoa population with intact plasma membrane, acrosome integrity, high mitochondrial membrane potential and pattern-F (least intracellular Ca²⁺), evidence of low lipid peroxidation and higher total antioxidant capacity in nano-purified groups. More number of spermatozoa were bound to zona pellucida of matured oocytes from nano-depleted than non-depleted group. The findings demonstrate antibody concentration of 1.0 μg/ml bio-conjugated with IONPs as most efficient in enriching the ejaculate with functional spermatozoa with the highest percentage of zona binding.

An overview of the role of metallic and nonmetallic nanoparticles and their salts during sperm cryopreservation and in vitro embryo manipulation

The cryopreservation of spermatozoa and the in vitro embryo production are valuable tools used in a variety of species, including humans, livestock, fish, and aquatic invertebrates. Sperm cryopreservation has been used to maintain or increase the genetic diversity of threatened species. Reactive oxygen species (ROS) are molecules derived from oxygen, being formed as byproducts of cellular metabolism. During cryopreservation of sperm and other in vitro manipulations of oocytes and embryos, ROS production is dramatically increased. In cells, low, medium, and high levels of ROS lead to different outcomes, apoptosis, auto-phagocytosis, and necrosis, respectively. ROS produced by cells can be neutralized by intracellular antioxidant systems, including enzymes as well as non-enzymatic antioxidants. Free radicals and oxidative stress can be major factors influencing in vitro manipulations. In this review, we discuss the role that metallic and nonmetallic nanoparticles and their salts play in the modulation of oxidative stress during in vitro embryo production and cryopreservation of sperm.

Relationship between sperm ubiquitination and equine semen freezability

This study aimed to assess the semen ubiquitin levels of stallions with good (GF) and poor semen freezability (PF) and to evaluate the relationship between sperm ubiquitination and sperm morphological defects. Five ejaculates from eight adult stallions (n=40) were collected and cryopreserved. Then, the ubiquitin level in equine sperm cells was assessed by immunohistochemistry with epifluorescence microscopy, and sperm morphology was assessed by differential interference contrast microscopy. Sperm cells were classified according to the intensity (classification 1: from I to IV; I = very low ubiquitin intensity and IV = very high ubiquitin intensity) and location of ubiquitin staining (classification 2). Statistical analyses were performed using SAS software (version 9.4), and P≤0.05 was considered significant. We observed that PF stallions showed higher percentages (P<0.05) of sperm cells with high ubiquitination (11.82% of ubiquitin intensity grade I, 39.13% of ubiquitin intensity grade II, 27.25% of ubiquitin intensity grade III, and 20.67% of grade IV), while GF stallions showed higher percentages (P<0.05) of sperm cells with lower staining intensity (28.52% grade I, 59.83% grade II, 7.92% grade III, and 7.02% grade IV). Furthermore, for PF stallions, 23 significant correlations were detected (P<0.05) between sperm abnormalities and ubiquitin intensity in different sperm regions. Increased ubiquitination of the sperm head, midpiece, and tail was positively correlated with their respective morphological defects. We concluded that high sperm ubiquitin levels are observed in ejaculates from stallions with poor semen quality (poor freezability), and ubiquitin marking in specific cellular locations can identify sperm morphological defects.

Pre-treatment of ram semen extender with magnetic nanoparticles on freeze-thawed spermatozoa

Background

Extensive use of different nanoparticles caused significant concerns about their biological safety.

Objective

This study aimed to evaluate the effects of cryopreservation on ram semen after adding magnetic nanoparticles (MNPs) to separate X and Y chromosome‐bearing spermatozoa.

Methods

The experimental ram sperms in this research included treated spermatozoa (50 μg/ml MNPs) and non‐treated spermatozoa. DNA damage of spermatozoa was examined using an acridine orange (AO) assay. Sperm viability, membrane functionality, abnormality and malondialdehyde (MDA) level were also measured.

Results

Results indicated that the pre‐treatment of ram semen extender with MNPs did not significantly affect the semen parameters such as viability, membrane functionality, abnormality, as well as lipid peroxidation (LPO) levels and DNA integrity in comparison with the control group (p < 0.05).

Conclusions

These observations suggest that pre‐treatment of ram semen extender with MNPs after semen sexing did not have adverse effects on different semen parameters after cryopreservation.

In the current study, we evaluated the effects of cryopreservation on ram semen after adding magnetic nanoparticles (MNPs), then after thawing some semen parameters were evaluated.

An Exploration of Current and Perspective Semen Analysis and Sperm Selection for Livestock Artificial Insemination

Artificial insemination of livestock has been a staple technology for producers worldwide for over sixty years. This reproductive technology has allowed for the rapid improvement of livestock genetics, most notably in dairy cattle and pigs. This field has experienced continuous improvements over the last six decades. Though much work has been carried out to improve the efficiency of AI, there are still many areas which continue to experience improvement, including semen analysis procedures, sperm selection techniques, sperm sexing technologies, and semen storage methods. Additionally, the use of AI continues to grow in beef cattle, horses, and small ruminants as the technology continues to become more efficient and yield higher pregnancy rates. In this review, AI trends in the various livestock species as well as cutting edge improvements in the aforementioned areas will be discussed at length. Future work will continue to refine the protocols which are used for AI and continue to increase pregnancy rates within all livestock species.

Simulating nature in sperm selection for assisted reproduction

Sperm selection in the female reproductive tract (FRT) is sophisticated. Only about 1,000 sperm out of millions in an ejaculate reach the fallopian tube and thus have a chance of fertilizing an oocyte. In assisted reproduction techniques, sperm are usually selected using their density or motility, characteristics that do not reflect their fertilization competence and, therefore, might result in failure to fertilize the oocyte. Although sperm processing in in vitro fertilization (IVF) and intrauterine insemination (IUI) bypasses many of the selection processes in the FRT, selection by the cumulus mass and the zona pellucida remain intact. By contrast, the direct injection of a sperm into an oocyte in intracytoplasmic sperm injection (ICSI) bypasses all natural selection barriers and, therefore, increases the risk of transferring paternal defects such as fragmented DNA and genomic abnormalities in sperm to the resulting child. Research into surrogate markers of fertilization potential and into simulating the natural sperm selection processes has progressed. However, methods of sperm isolation - such as hyaluronic acid-based selection and microfluidic isolation based on sperm tactic responses - use only one or two parameters and are not comparable with the multistep sperm selection processes naturally occurring within the FRT. Fertilization-competent sperm require a panel of molecules, including zona pellucida-binding proteins and ion channel proteins, that enable them to progress through the FRT to achieve fertilization. The optimal artificial sperm selection method will, therefore, probably need to use a multiparameter tool that incorporates the molecular signature of sperm with high fertilization potential, and their responses to external cues, within a microfluidic system that can replicate the physiological processes of the FRT in vitro.

Role of nanotechnology in animal production and veterinary medicine

Nanotechnology is the discipline and technology of small and specific things that are < 100 nm in size. Because of their extremely miniscule size, any changes in their chemical and physical structure may show higher reactivity and solubility than larger particles. Nanotechnology plays a vital role in every field of life. It is considered one of the most bleeding edge field of scientific research. It has already several applications in a myriad of disciplines while its application in the field of animal production and veterinary medicine is still experimental in nature. But, in recent years, the role of nanotechnology in the aforementioned fields of scientific inquiry has shown great progress. These days, nanotechnology has been employed to revolutionize drug delivery systems and diagnose atypical diseases. Applications of nanoparticle technology in the field of animal reproduction and development of efficacious vaccines have been at the forefront of scientific endeavors. Additionally, their impacts on meat and milk quality are also being judiciously inquired in recent decades. Veterinary nanotechnology has great potential to improve diagnosis and treatment, and provide new tools to this field. This review focuses on some noteworthy applications of nanoparticles in the field of animal production and their future perspectives.

Comparison of the uterine inflammatory response to frozen-thawed sperm from high and low fertility bulls

Some bulls with apparently normal semen quality yield unacceptably low pregnancy rates. We hypothesised that a differential uterine immunological response to sperm from high and low fertility bulls may contribute to these differences. The experimental model used was heifer follicular phase uterine explants incubated with frozen-thawed sperm from high and low fertility bulls (3-5 replicates per experiment). Inflammatory gene expression of IL1A, IL1B, IL6, TNFA and CXCL8 were assessed by qPCR and IL1-β and IL-8 were quantified in explant supernatants by ELISA. Neutrophil binding affinity to sperm from high and low fertility bulls was also assessed. There was a significant up-regulation of IL1A, IL1B and TNFA from frozen-thawed sperm, irrespective of fertility status, compared to the unstimulated control. This response was confirmed at the protein level, with an increase of IL-1β and IL-8 protein concentrations by 5 and 2.7 fold, respectively (P < 0.05). Although no significant differences in the inflammatory response at the gene or protein level were evident between high and low fertility bulls, more sperm from low compared to high fertility bulls bound to neutrophils (P < 0.05). Using bulls of unknown fertility, cauda epididymal sperm (CES) plus seminal plasma (SP) upregulated IL6 (P < 0.05) but there was no upregulation of any inflammatory gene expression for CES alone. Overall, this ex vivo study demonstrated an upregulation of inflammatory gene expression in the uterus in response to frozen-thawed bull sperm. While there was no difference between sperm from high and low fertility bulls, there was a greater binding affinity of low fertility sperm by neutrophils.

Metal Oxide Nanoparticles: Evidence of Adverse Effects on the Male Reproductive System

Metal oxide nanoparticles (MONPs) are inorganic materials that have become a valuable tool for many industrial sectors, especially in healthcare, due to their versatility, unique intrinsic properties, and relatively inexpensive production cost. As a consequence of their wide applications, human exposure to MONPs has increased dramatically. More recently, their use has become somehow controversial. On one hand, MONPs can interact with cellular macromolecules, which makes them useful platforms for diagnostic and therapeutic interventions. On the other hand, research suggests that these MONPs can cross the blood–testis barrier and accumulate in the testis. Although it has been demonstrated that some MONPs have protective effects on male germ cells, contradictory reports suggest that these nanoparticles compromise male fertility by interfering with spermatogenesis. In fact, in vitro and in vivo studies indicate that exposure to MONPs could induce the overproduction of reactive oxygen species, resulting in oxidative stress, which is the main suggested molecular mechanism that leads to germ cells’ toxicity. The latter results in subsequent damage to proteins, cell membranes, and DNA, which ultimately may lead to the impairment of the male reproductive system. The present manuscript overviews the therapeutic potential of MONPs and their biomedical applications, followed by a critical view of their potential risks in mammalian male fertility, as suggested by recent scientific literature.

Implications of cryopreservation on structural and functional attributes of bovine spermatozoa: An overview

Sperm cryopreservation is an important adjunct to assisted reproduction techniques (ART) for improving the reproductive efficiency of dairy cattle and buffaloes. Improved understanding of mechanisms and challenges of bovine semen cryopreservation is vital for artificial insemination on a commercial basis. Although cryopreservation of bovine spermatozoa is widely practiced and advanced beyond that of other species, there are still major gaps in the knowledge and technology. Upon cryopreservation, disruption of spermatozoal plasma membrane configuration due to alterations in metabolic pathways, enzymes and antioxidants activity add to lower efficiency with loss of sperm longevity and fertilising ability. Therefore, the effective amalgamation of cryo-variables like ambient temperature, cooling and thawing rates, nucleation temperature, type and concentration of the cryoprotectant, seminal plasma composition, free radicals and antioxidant status are required to optimise cryopreservation. Novel strategies like supplementation of cholesterol-loaded cyclodextrins (CLC), nanovesicles, osteopontin, antioxidants, etc., in an extender and recent techniques like nano-purification and modified packaging have to be optimised to ameliorate the cryodamage. This article is intended to describe the basic facts about the sperm cryopreservation process in bovine and the associated biochemical, biophysical, ultra-structural, molecular and functional alterations.

Recovery of sperms bearing X chromosomes with different concentrations of magnetic nanoparticles in ram

Pre-conceptual sex selection is still a highly debatable process whereby X and Y chromosome bearing spermatozoa are isolated before oocyte fertilization. Recently, magnetic nanoparticles (MNP) have been used to determine X and Y chromosomes bearing spermatozoa as a result of searching for a cheap, highly efficient method using non-toxic materials. This study aimed to recover the sperm bearing X chromosomes in ram with different concentrations of MNP and then evaluate the success of this method using polymerase chain reaction (PCR). Ram sperms were divided into four groups, treated with 0 (control), 50, 100 and 200 μg/ml MNP, respectively. MNP was used to restore sperm cells bearing X chromosomes. Upon recovery, the PCR was performed to identify the X and Y sperms, Methyl ThiazoleTetrazolium (MTT), to assess MNP toxicity and sperm viability and acridine orange (AO) to evaluate sperm DNA integrity. The results of PCR revealed that the treatment of spermatozoa- bearing X chromosomes with 50 μg/ml MNP had the highest effects on the recovery of X sperm rather than the other concentrations of MNP. However, the concentrations of MNP did not have any toxic effects on spermatozoa, sperm viability and, DNA integrity, but the high concentration of MNP (200 μg/ml) significantly reduced DNA integrity. According to MTT and AO results, the concentrations of MNP used in this study had no toxic effects on spermatozoa and did not reduce the sperm viability and DNA integrity, except that 200 μg/ml MNP significantly reduced DNA integrity.

The Current Trends in Using Nanoparticles, Liposomes, and Exosomes for Semen Cryopreservation

Cryopreservation is an essential tool to preserve sperm cells for zootechnical management and artificial insemination purposes. Cryopreservation is associated with sperm damage via different levels of plasma membrane injury and oxidative stress. Nanoparticles are often used to defend against free radicals and oxidative stress generated through the entire process of cryopreservation. Recently, artificial or natural nanovesicles including liposomes and exosomes, respectively, have shown regenerative capabilities to repair damaged sperm during the freeze-thaw process. Exosomes possess a potential pleiotropic effect because they contain antioxidants, lipids, and other bioactive molecules regulating and repairing spermatozoa. In this review, we highlight the current strategies of using nanoparticles and nanovesicles (liposomes and exosomes) to combat the cryoinjuries associated with semen cryopreservation.

Purification of cryopreserved camel spermatozoa following protease-based semen liquefaction by lectin-functionalized DNA-defrag magnetic nanoparticles

Although incorporating proteases into sperm medium is considered the most effective procedure to eliminate camel semen viscosity, it drastically affects viability, morpho-functional properties and, hence, fertilization potential of spermatozoa. The present work aimed at evaluating adequacy of employing magnetic nanoparticles-based sperm purification technique for eluting impaired and apoptotic camel spermatozoa from cryopreserved semen doses following protease-based semen liquefaction. Thirty cryopreserved semen doses (50 x 10⁶ sperm/straw) representing the following liquefaction treatments: control (untreated), 0.1 mg/ml papain or 5 U/ml bromelain were used (n = 10 straws per treatment). Immediately after thawing (38°C for 40 s), sperm concentration of each straw within treatment was readjusted to 15 x 10⁶ sperm/mL by dilution in PBS (37°C). Sperm physical and cytological properties were then assessed (non-purified semen). Thereafter, each specimen was subjected to lectin-functionalized DNA-defrag magnetic nanoparticles sperm purification, and the same sperm traits were re-evaluated after undergoing purification (purified semen). Sperm DNA fragmentation level within each group, prior to and after magnetic nano-purification, was also determined by fluorescent imaging. The results showed a dramatic improvement (p < .05) in post-thaw motility (%), viability (%), normal sperm (%), intact acrosome (%) and HOST-reacted (%) spermatozoa in protease-liquefied semen following sperm magnetic nano-purification. Additionally, the highest (p < .05) DNA fragmentation level was recorded in all cryopreserved semen groups prior to purification, whereas the lowest (p < .05) was observed in the protease-treated specimens after magnetic nano-purification. These results indicate that protease-based semen liquefaction prior to cryopreservation in conjunction with magnetic nano-purification post-thawing holds potential for reducing the proportion of damaged and dead spermatozoa, hence improving camel sperm fertilization competence.

Synthesis of iron oxide nanoparticles-antiubiquitin antibodies conjugates for depletion of dead/damaged spermatozoa from buffalo (Bubalus bubalis) semen

The synthesis of iron oxide nanoparticles (IONPs)-antiubiquitin antibodies (Abs) complex for depletion of dead/damaged spermatozoa from buffalo semen was done. The IONPs synthesized were round in shape with size of 12.09 ± 0.91 nm. At the end of the two-step functionalization, that is, silanization and pegylation of bare IONPs and bioconjugation of functionalized IOPNs, particles with the sizes of 19.15 ± 1.46, 20.72 ± 0.95, and 73.01 ± 7.56 nm, respectively, were obtained. Twenty-four semen samples from four bulls with mean individual progressive motility (%) and sperm concentration (million/mL) of 77.1 ± 0.9 and 1,321.2 ± 84.7, respectively, were divided into Group I (control), and treatment groups viz. Groups II, III, and IV; with each group containing 150 ± 25 million dead/damaged spermatozoa. The IONPs-Abs complex was added at the ratio of 1:1 (0.5 μg/mL), 1:2 (1.0 μg/mL), and 1:4 (2.0 μg/mL), respectively, in the Groups II, III, and IV. The mean efficiency (%) of nanopurification was estimated to be greater in nanopurified semen with the increasing doses of the IONPs-Abs complex. A reduction of 29.3 ± 6.4%, 48.4 ± 5.3%, and 55.4 ± 4.4% in dead/damaged spermatozoa following nanopurification in Groups II, III, and IV, respectively, was observed. The study shows that in-house synthesized IONPs-Abs complex can be successfully used to deplete dead/damaged spermatozoa from buffalo semen with improvement in quality.

Magnetic Iron Oxide Nanoparticle (IONP) Synthesis to Applications: Present and Future

Iron oxides are chemical compounds which have different polymorphic forms, including γ-Fe2O3 (maghemite), Fe3O4 (magnetite), and FeO (wustite). Among them, the most studied are γ-Fe2O3 and Fe3O4, as they possess extraordinary properties at the nanoscale (such as super paramagnetism, high specific surface area, biocompatible etc.), because at this size scale, the quantum effects affect matter behavior and optical, electrical and magnetic properties. Therefore, in the nanoscale, these materials become ideal for surface functionalization and modification in various applications such as separation techniques, magnetic sorting (cells and other biomolecules etc.), drug delivery, cancer hyperthermia, sensing etc., and also for increased surface area-to-volume ratio, which allows for excellent dispersibility in the solution form. The current methods used are partially and passively mixed reactants, and, thus, every reaction has a different proportion of all factors which causes further difficulties in reproducibility. Direct active and complete mixing and automated approaches could be solutions to this size- and shape-controlled synthesis, playing a key role in its exploitation for scientific or technological purposes. An ideal synthesis method should be able to allow reliable adjustment of parameters and control over the following: fluctuation in temperature; pH, stirring rate; particle distribution; size control; concentration; and control over nanoparticle shape and composition i.e., crystallinity, purity, and rapid screening. Iron oxide nanoparticle (IONP)-based available clinical applications are RNA/DNA extraction and detection of infectious bacteria and viruses. Such technologies are important at POC (point of care) diagnosis. IONPs can play a key role in these perspectives. Although there are various methods for synthesis of IONPs, one of the most crucial goals is to control size and properties with high reproducibility to accomplish successful applications. Using multiple characterization techniques to identify and confirm the oxide phase of iron can provide better characterization capability. It is very important to understand the in-depth IONP formation mechanism, enabling better control over parameters and overall reaction and, by extension, properties of IONPs. This work provides an in-depth overview of different properties, synthesis methods, and mechanisms of iron oxide nanoparticles (IONPs) formation, and the diverse range of their applications. Different characterization factors and strategies to confirm phase purity in the IONP synthesis field are reviewed. First, properties of IONPs and various synthesis routes with their merits and demerits are described. We also describe different synthesis strategies and formation mechanisms for IONPs such as for: wustite (FeO), hematite (α-Fe2O3), maghemite (ɤ-Fe2O3) and magnetite (Fe3O4). We also describe characterization of these nanoparticles and various applications in detail. In conclusion, we present a detailed overview on the properties, size-controlled synthesis, formation mechanisms and applications of IONPs.

Sperm content of TXNDC8 reflects sperm chromatin structure, pregnancy establishment, and incidence of multiple births after ART

Male germline-specific thioredoxin domain containing 8 (TXNDC8; alias SPTRX3) accumulates indefective human spermatozoa. We assessed the efficiency of two-step semen purification inremoving spermatozoa carrying TXNDC8, and examined the relationship of TXNDC8 with theoutcomes of assisted reproductive therapy (ART), conventional semen parameters, and sperm DNA integrity in sperm chromatin structure assay (SCSA). Semen samples (n = 255) from 91 ART couples were screened in two independent trials, both including a two-step, gradient-and-swim-up separation procedure yielding A-samples (raw semen), B-samples (gradient separated), and C-samples (gradient-and-swim-up). The C-samples were used for intracytoplasmic sperm injection (ICSI) with morphologically selected spermatozoa (IMSSI). Percentage of TXNDC8-positive spermatozoaincreased progressively from A to B/C-samples in both trials. In the first trial (35 couples), the TXNDC8 correlated positively with sperm DNA fragmentation index (%DFI; r = 0.66) measured before separation, and negatively with sperm concentration (r = -0.57) and motility (r = -0.67), also taken before separation. The high DNA stainability index (%HDS) correlated with the percentage of spermatozoa lacking TXNDC8 (r = 0.68). Both SCSA and TXNDC8 parameters showed moderate correlations (r = 0.33-0.66) with blood serum levels of hCG on day 11 (Beta 1) and day13 (Beta 2) after oocyte retrieval. In the second trial (56 couples), fathers of multiplets had a significantly lower percentage of TXNDC8-positive spermatozoa in B-sample (gradient separationonly) compared to men who conceived a singleton pregnancy (p = 0.01) and those who produced no pregnancy (p = 0.02). Those multiplets' fathers also had a significantly higher sperm concentration while their SCSA parameters did not differ from others. It is concluded that theTXNDC8 levels correlate with SCSA and conventional raw semen parameters, and are predictive of pregnancy outcome and multiple births after ART. Two-step purification does not efficiently remove TXNDC8 carrying spermatozoa.

ABBREVIATIONS

ART- assisted reproductive therapy; DFI- DNA fragmentation index; FC- flow cytometry (FC); hCG: human chorionic gonadotropin; HDS: high DNA stainability index; HEPES- (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid); HTF- human tubal fluid; ICSI- intracytoplasmic sperm injection; IgG- immunoglobulin G; IMSSI- ICSI with morphologically selected spermatozoa; IVF- in vitro fertilization; IU-: intrauterine insemination; NGS- normal goat serum; PBS- phosphate buffered saline; PVP- polyvinylpyrrolidone; SAB- spontaneous abortion; SCSA- sperm chromatin structure assay; SPTRX3- spermatid specific thioredoxin 3; SSS- synthetic serum substitute; TRITC- tetramethyl rhodamine isothiocyanate; TX-100- Triton X-100; TXNDC- thioredoxin domain-containing proteins; TXNDC8- thioredoxin domain containing 8; TUNEL- Terminal deoxynucleotidyl transferase dUTP nick end labeling.

Iron Oxide Nanoparticles as an Alternative to Antibiotics Additive on Extended Boar Semen

This study examined the effect of Fe₃O₄ nanoparticles on boar semen. Beltsville thawing solution without antibiotics was used to extend ejaculates from 5 boars (4 ejaculates/boar). Semen samples of control group (C) and group with Fe₃O₄ (Fe; 0.192 mg/mL semen) were incubated under routine boar semen storage temperature (17 °C) for 0.5 h and nanoparticles were removed by a magnetic field. Before and after treatment, aliquots of all groups were cultured using standard microbiological methods. The samples after treatment were stored (17 °C) for 48 h and sperm parameters (computer-assisted sperm analyzer (CASA) variables; morphology; viability; hypo-osmotic swelling test (HOST); DNA integrity) were evaluated at storage times 0, 24, 48 h. Semen data were analyzed by a repeated measures mixed model and microbial data with Student’s t-test for paired samples. Regarding CASA parameters, Fe group did not differ from C at any time point. In group C, total motility after 24 h and progressive motility after 48 h of storage decreased significantly compared to 0 h. In group Fe, linearity (LIN) after 48 h and head abnormalities after 24 h of storage increased significantly compared to 0 h. The microbiological results revealed a significant reduction of the bacterial load in group Fe compared to control at both 24 and 48 h. In conclusion, the use of Fe₃O₄ nanoparticles during semen processing provided a slight anti-microbiological effect with no adverse effects on sperm characteristics.

Nano-purification of raw semen minimises oxidative stress with improvement in post-thaw quality of buffalo spermatozoa

The study consisted of application of anti-ubiquitin antibodies (Abs)-coated iron oxide-nanoparticles (IONPs) for minimisation of oxidative stress to contemporary live spermatozoa from the raw semen. Round-shaped IONPs (12.09 ± 0.91 nm) after two-stage functionalisation (silanisation and pegylation) were conjugated with Abs. Four aliquots from each of the 24 ejaculates (4 buffalo bulls) formed Control (Group I) and treatment (II, III and IV) groups; each containing 150 ± 25 million dead/damaged spermatozoa. IONPs-Abs complex were added at ratio of 1:1 (0.5 µg/ml), 1:2 (1.0 µg/ml) and 1:4 (2.0 µg/ml), respectively, in Groups II, III and IV. The semen quality parameters showed improvement at lag-stage (post-nano-purification before processing for cryopreservation). The mean post-thaw motility (%) in Group IV was found to be greater (p < .05) than Group I. Moreover, the overall DNA integrity (%) at post-thaw stage was improved in the nano-purified semen samples. The value of malondialdehyde was greater (p < .001) in Group I than Groups II, III and IV. The mean total antioxidant capacity and superoxide dismutase (U/mg protein) activity values in Group IV was greater (p < .05) than Group I. The study results show that IONPs conjugated with anti-ubiquitin Abs at 2.0 µg/ml can be an effective dose for depletion of dead/damaged spermatozoa from buffalo ejaculates to minimise oxidative stress.

State-of-the-Art and Prospective of Nanotechnologies for Smart Reproductive Management of Farm Animals

Many biotechnological assisted reproductive techniques (ART) are currently used to control the reproductive processes of farm animals. Nowadays, smart ART that considers technique efficiency, animal welfare, cost efficiency and environmental health are developed. Recently, the nanotechnology revolution has pervaded all scientific fields including the reproduction of farm animals, facilitating certain improvements in this field. Nanotechnology could be used to improve and overcome many technical obstacles that face different ART. For example, semen purification and semen preservation processes have been developed using different nanomaterials and techniques, to obtain semen doses with high sperm quality. Additionally, nanodrugs delivery could be applied to fabricate several sex hormones (steroids or gonadotrophins) used in the manipulation of the reproductive cycle. Nanofabricated hormones have new specific biological properties, increasing their bioavailability. Applying nanodrugs delivery techniques allow a reduction in hormone dose and improves hormone kinetics in animal body, because of protection from natural biological barriers (e.g., enzymatic degradation). Additionally, biodegradable nanomaterials could be used to fabricate hormone-loaded devices that are made from non-degradable materials, such as silicon and polyvinyl chloride-based matrixes, which negatively impact environmental health. This review discusses the role of nanotechnology in developing some ART outcomes applied in the livestock sector, meeting the concept of smart production.

Nano-depletion of acrosome-damaged donkey sperm by using lectin peanut agglutinin (PNA)-magnetic nanoparticles

Lectin is considered as a suitable biomarker for nano-depletion of acrosome-damaged sperm. The aim of this study was to synthetize magnetic nanoparticles (MNPs) coated by peanut (Arachis hypogaea) agglutinin lectin (PNA) and investigate its beneficial effect in improving of sperm characteristics. MNPs were obtained by co-precipitation method, functionalized with chitosan and coated by PNA at a concentration of 0.04 mg/mL. Semen was frozen either with glycerol-based or sucrose-based extenders. Frozen-thawed straws from five donkeys (three ejaculates per donkey) were incubated with lectin-MNPs (2 mg/mL), and then exposed to an external magnet enabling the non-bound sperm to be collected as nanopurified sperm. Sperm were evaluated post-thawing (control) and after nanopurification for motility, plasma membrane integrity, acrosome integrity, morphology, DNA fragmentation and concentration. The statistical analyses were extended to investigate the correlation between the initial quality of the frozen-thawed semen samples and the effect of nanopurification after thawing. The obtained MNPs were biocompatible to the sperm and significantly improved the progressive motility (P < 0.05) for the glycerol nanopurified group (43.08 ± 3.52%) in comparison to control (33.70 ± 2.64%). Acrosome-damaged sperm were reduced (P < 0.05) in both nanopurified groups (19.92 ± 2.69 for G and 21.57 ± 2.77 for S) in comparison to control (36.07 ± 3.82 for G and 35.35 ± 3.88 for S). There were no significant changes in sperm morphology and membrane integrity after nanopurification. The average sperm recovery after nanopurification was 80.1%. Sperm quality index was significantly higher (P < 0.001) in nanopurified groups regardless of the initial quality of the frozen thawed semen samples. However, in the high sperm quality group, nanopurification significantly improved the progressive motility and membrane integrity besides the increasing of acrosome-intact sperm. Sperm nanopurification using lectin-magnetic nanoparticles can be considered as a suitable method to reduce the proportion of acrosome-damaged sperm and to increase the quality of frozen thawed donkey semen.

Nanomaterials and nanocomposite applications in veterinary medicine

Nowadays, nanotechnology has made huge, significant advancements in biotechnology and biomedicine related to human and animal science, including increasing health safety, production, and the elevation of national income. There are various fields of nanomaterial applications in veterinary medicine such as efficient diagnostic and therapeutic tools, drug delivery, animal nutrition, breeding and reproduction, and valuable additives. Additional benefits include the detection of pathogens, protein, biological molecules, antimicrobial agents, feeding additives, nutrient delivery, and reproductive aids. There are many nanomaterials and nanocomposites that can be used in nanomedicine such as metal nanoparticles, liposomes, carbon nanotubes, and quantum dots. In the near future, nanotechnology research will have the ability to produce novel tools for improving animal health and production. Therefore, this chapter was undertaken to spotlight novel methods created by nanotechnology for application in the improvement of animal health and production. In addition, the toxicity of nanomaterials is fully discussed to avoid the suspected health hazards of toxicity for animal health safety.

Transfer of orally administered ZnO:Eu nanoparticles through the blood-testis barrier: the effect on kinetic sperm parameters and apoptosis in mice testes

Zinc-based nanoparticles are promising materials for various applications, including in biomedicine. The aim of our study was to determine the effect of fluorescent europium-doped zinc oxide nanoparticles (ZnO:Eu NPs) on sperm parameters, cell apoptosis and integrity of the blood-testis barrier (BTB) in mice. Nanostructures were orally administered to adult mice (n = 34). Animals were sacrificed after 3 h, 24 h, 7 d and 14 d following oral administration. Sperm was collected and analysed for viability and kinetic parameters. Collected testes were quantitatively analysed for accumulation of ZnO:Eu NPs. Microscopic evaluation based on immunofluorescence and histopathological studies were also conducted. Results showed that ZnO:Eu NPs were able to overcome the BTB with their subsequent accumulation in the testis. No toxic or pro-apoptotic effects of nanoparticles on the male reproductive system were observed. The results suggested that ZnO:Eu NPs were able to accumulate in the testis with no negative impact on sperm parameters, tissue architecture or the integrity of the BTB.

Applications of omics and nanotechnology to improve pig embryo production in vitro

An appropriate environment to optimize porcine preimplantation embryo production in vitro is required as genetically modified pigs have become indispensable for biomedical research and agriculture. To provide suitable culture conditions, omics technologies have been applied to elucidate which metabolic substrates and pathways are involved during early developmental processes. Metabolomic profiling and transcriptional analysis comparing in vivo- and in vitro-derived embryos have demonstrated the important role of amino acids during preimplantation development. Transcriptional profiling studies have been helpful in assessing epigenetic reprogramming agents to allow for the correction of gene expression during the cloning process. Along with this, nanotechnology, which is a highly promising field, has allowed for the use of engineered nanoplatforms in reproductive biology. A growing number of studies have explored the use of nanoengineered materials for sorting, labeling, and targeting purposes; which demonstrates their potential to become one of the solutions for precise delivery of molecules into gametes and embryos. Considering the contributions of omics and the recent progress in nanoscience, in this review, we focused on their emerging applications for current in vitro pig embryo production systems to optimize the generation of genetically modified animals.

Strategies to Minimize Various Stress-Related Freeze-Thaw Damages During Conventional Cryopreservation of Mammalian Spermatozoa

The aim of the article is to report a review on different sperm cryopreservation techniques, various stress-related freeze-thaw damages altering sperm structure and function during conventional cryopreservation, and strategies to minimize these stresses. Sperm cryopreservation has allowed indefinite storage and successful transportation of valuable germplasm from proven sites at distant locations, for genetic upgradation through implementation of reproductive techniques, such as artificial insemination. Different techniques for sperm cryopreservation have been proposed such as conventional freezing techniques, directional freezing, and sperm vitrification. Drawbacks related to conventional freezing methods, such as heterogeneous ice nucleation and repeated freeze-thaw cycles at the ice front that disrupts and kill sperm cells, led to the emergence of the directional freezing technique. Sperm vitrification is advantageous as there is no ice crystal-induced physical damages to sperm. However, sperm vitrification has less applicability as encouraging results are only reported in human, dog, and cat. In spite of several drawbacks, conventional freezing techniques are still most widely used for sperm cryopreservation. Spermatozoa experience stresses in the form of cold shock, osmotic stress, and mainly oxidative stress during conventional cryopreservation ultimately reduces the sperm viability and fertility. Several attempts have been made in the past to minimize all these stresses individually or in combination. Membrane fluidity was increased to prevent the cold shock and cryocapacitation-like changes by the addition of cholesterol to the membrane. Antifreeze proteins were added in semen extender to minimize freeze-thaw damages due to heterogeneous ice nucleation and ice recrystallization. Oxidative stress was reduced either by neutralizing reactive oxygen species (ROS) through enzymatic, nonenzymatic, plant-based antioxidants or reductants; or by minimizing the level of sources like the semen radiation exposure, leucocytes, and dead and defective spermatozoa, which lead to ROS production during the semen cryopreservation process. A novel approach of minimizing oxidative stress was to reduce the oxygen tension in sperm microenvironment that is, extender by partial deoxygenation process, as a number of literatures pointed out direct link of O₂ with ROS production. When compared with other strategies, partial deoxygenation of semen extender with N₂ gassing is found as a cost-effective, comparatively easy and a potential approach to large-scale frozen semen production.

Cellular effects of diquat dibromide exposure: Interference with Wnt signaling and cytoskeletal development

The herbicidal action of diquat dibromide (DD) on plant cells is due primarily to the initiation of reactive oxygen species (ROS) formation, lipoperoxidation, and apoptotic cell death. It has been demonstrated that oxidative stress also occurs in animal cells exposed to high concentrations of DD; however, observations of DD’s effects on animal cells at concentrations below the reported ROS-initiation threshold suggest that some of these effects may not be attributable to ROS-induced cell death. Our results suggest that DD causes disruption of the Wnt pathway, calcium dysregulation, and cytoskeletal damage during development. Using embryos of the pond snail Lymnaea palustris as our model organism, we observed increased mortality, developmental delay and abnormality, altered motility, calcium dysregulation, decreased heart rate, and arrhythmia in embryos exposed to DD. Sperm extracted from adult snails that were exposed to DD exhibit altered motility, increased abundance, and high mortality. Effects were quantified via real-time imaging, heart rate assessment, flow cytometry, and mortality scoring. We propose that there are two models for the mechanism of DD’s action in animal cells: at low concentrations (≤28 µg/L), apoptotic cell death does not occur, but cytoskeletal elements, calcium regulation, and Wnt signaling are compromised, causing irreversible damage in L. palustris embryos; such damage is partially remediated with antioxidants or lithium chloride. At high concentrations of DD (≥44.4 µg/L), calcium dysregulation may be triggered, leading to the establishment of an intracellular positive feedback loop of ROS formation in the mitochondria, calcium release from the endoplasmic reticulum, calcium efflux, and apoptotic cell death. Permanent cellular damage occurring from exposure to sublethal concentrations of this widespread herbicide underscores the importance of research that elucidates the mechanism of DD on nontarget organisms.

Treatment of boar sperm with nanoparticles for improved fertility

Continuous progress in nanoscience has allowed the synthesis of various nanoscale particles, known as nanoparticles or nanomaterials which, by harnessing unique physico-chemical properties, are crucial for multiple bio-applications. Despite the revealed toxicity (nanotoxicity) of nanoparticles in various in vitro and in vivo studies, their careful design for biocompatibility and effective interactions with single-celled and multi-cellular organisms has permitted their use in several fields of research and biomedicine. The various nanoparticles synthesized and applied in the veterinary sciences, including reproductive biology, have shown potential to influence routine practices in animal production systems. These include post-collection manipulation of semen and the protection of high-quality spermatozoa to extend their preservation, and to improve sperm-related biotechnologies such as sperm-mediated gene transfer, sperm sorting, sex-sorting, and cryopreservation. Therefore, the application of nanotechnology-based tools to semen may enhance assisted reproductive technologies for biomedical applications and improve economic productivity for farmers. Here, we review the efficacy of available techniques and emerging tools of nanotechnology that might be useful for further selection of high quality boar spermatozoa and productivity improvement.

Boar semen improvement through sperm capacitation management, with emphasis on zinc ion homeostasis

Critical to fertilization success, sperm capacitation within the female oviductal sperm reservoir endows mammalian spermatozoa with hyperactivated motility and capacity to fertilize. An elaborate cascade of signaling events during capacitation guides the redistribution of sperm plasma membrane seminolipid and cholesterol, Ca-influx and increases tyrosine phosphorylation to promote hyperactivated motility. Such events result in the remodeling of the sperm acrosome, increased fluidity and fusability of the plasma membrane, shedding of surface-adsorbed seminal plasma proteins that glue sperm heads to the oviductal epithelium and ultimately the release of hyperactivated spermatozoa from the oviductal sperm reservoir. Discovered recently, the capacitation-induced sperm zinc ion efflux and resultant zinc signatures are reflective of sperm capacitation status and fertilizing ability, inspiring the retrospection of zinc ion functions in the physiology and fertility of boar sperm and that of other species. This review also highlights the merit of the domestic boar as a biomedical model for spermatology and fertilization research. Relevant to the quest for better fertility management in the livestock industries, the benefits of zinc ion supplementation through nutrition and direct addition to extended semen are discussed in the context of artificial insemination (AI). Ideas are shared on future technologies for zinc management in AI doses and research on the sperm zinc-interacting proteome.

Nanotechnology-based approach for safer enrichment of semen with best spermatozoa

BACKGROUND

Advances in nanotechnology have permitted molecular-based targeting of cells through safe and biocompatible magnetic nanoparticles (MNP). Their use to detect and remove damaged spermatozoa from semen doses could be of great interest. Here, MNP were synthesized and tested for their ability to target apoptotic (annexin V) and acrosome-reacted (lectin) boar spermatozoa, for high-throughout retrieval in a magnetic field (nanoselection). The potential impacts of nanoselection on sperm functions and performance of offspring sired by sperm subjected to nanoselection were determined. Fresh harvested and extended boar semen was mixed with various amounts (0, 87.5, and 175 μg) of MNP-conjugates (Annexin V-MNP or Lectin-MNP) and incubated (10 to 15 min) for 37 °C in Exp. 1. In Exp. 2, extended semen was mixed with optimal concentrations of MNP-conjugates and incubated (0, 30, 90, or 120 min). In Exp. 3, the synergistic effects of both MNP-conjugates (87.5 μg - 30 min) on spermatozoa was evaluated, followed by sperm fertility assessments through pregnancy of inseminated gilts and performance of neonatal offspring. Sperm motion, viability, and morphology characteristics were evaluated in all experiments.

RESULTS

Transmission electron microscopy, atomic force microscopy, and hyperspectral imaging techniques were used to confirm attachment of MNP-conjugates to damaged spermatozoa. The motility of nanoselected spermatozoa was improved (P < 0.05). The viability of boar sperm, as assessed by the abundance of reactive oxygen species and the integrity of the acrosome, plasma membrane, and mitochondrial membrane was not different between nanoselected and control spermatozoa. The fertility of gilts inseminated with control or nanoselected spermatozoa, as well as growth and health of their offspring were not different between (P > 0.05).

CONCLUSIONS

The findings revealed the benefit of magnetic nanoselection for high-throughput targeting of damaged sperm, for removal and rapid and effortless enrichment of semen doses with highly motile, viable, and fertile spermatozoa. Therefore, magnetic nanoselection for removal of abnormal spermatozoa from semen is a promising tool for improving fertility of males, particularly during periods, such as heat stress during the summer months.

Perspectives of nanotechnology in male fertility and sperm function

Recent advances in nanotechnology have tremendously expanded its possible applications in biomedicine. Although, the effects of nanoparticles (NPs) at cellular and tissue levels have not been fully understood, some of these biological effects might be employed in assisted reproduction to improve male fertility particularly by enhancing sperm cell quality either in vivo or in vitro. This review summarises the available literature regarding the potential applications of nanomaterials in farm animal reproduction, with a specific focus on the male gamete and on different strategies to improve breeding performances, transgenesis and targeted delivery of substances to a sperm cell. Antioxidant, antimicrobial properties and special surface binding ligand functionalization and their applications for sperm processing and cryopreservation have been reviewed. In addition, nanotoxicity and detrimental effects of NPs on sperm cells are also discussed due to the increasing concerns regarding the environmental impact of the expanding use of nanotechnologies on reproduction.

Prognostic value of post thaw semen quality parameters, mitochondrial integrity and cholesterol content of sperm membrane vis-à-vis conception rate in Frieswal bulls

The present study aimed to analyze the quantitative relationship of membrane cholesterol content (Chol content), mitochondrial integrity (Δψm), and quality parameters of spermatozoa (SQP) at post-thaw stage with conception rate (CR) and estimated relative conception rate (ERCR) in Frieswal bulls. For the experiment, frozen semen straws (32) were collected from the SF laboratory and CR (Total insemination 3482) was obtained from Field Progeny Testing units. Based on the CR, bulls were grouped into low, medium or high groups (G I, G II and G III, respectively). SQP, viz. viability (Eosin Nigrosin), post thaw motility, biochemical integrity of the membrane (HOS res), acrosome integrity (Giemsa, and fluorochromes fluorescein isothiocyanate Pisum sativum agglutinin and propidium iodide, respectively), chol-content, and Δψm using fluorescent probe JC-1 (5,5’,6,6’-tetrachloro- 1,1’,3,3’-tetraethylbenzimi-dazolylcarbocyanine iodide) were determined. The values thus obtained were subjected to the stepwise regression analysis using the least squares principles for each group, and the CR and ERCR were regressed on the various SQP. Pearson’s correlation coefficients were estimated between the CR and ERCR values and the various SQPs. The coefficient of determination (R2) moderately higher for all the models and ranged from 63.70–93.40% (high and medium group, respectively). High R2 value of the prediction equation for the herd and bulls with medium CR (75.9 and 93.4%, respectively) reveal their suitability to predict the CR and ERCR potential of the cryopreserved semen. Study results point to inclusion of cholesterol content and Δψm estimation in routine semen analysis before long-term storage or usage for insemination purposes.

Live births from artificial insemination of microfluidic-sorted bovine spermatozoa characterized by trajectories correlated with fertility

Selection of functional spermatozoa plays a crucial role in assisted reproduction. Passage of spermatozoa through the female reproductive tract requires progressive motility to locate the oocyte. This preferential ability to reach the fertilization site confers fertility advantage to spermatozoa. Current routine sperm selection techniques are inadequate and fail to provide conclusive evidence on the sperm characteristics that may affect fertilization. We therefore developed a selection strategy for functional and progressively motile bovine spermatozoa with high DNA integrity based on the ability to cross laminar flow streamlines in a diffuser-type microfluidic sperm sorter (DMSS). The fluid dynamics, with respect to microchannel geometry and design, are relevant in the propulsion of spermatozoa and, consequently, ultrahigh-throughput sorting. Sorted spermatozoa were assessed for kinematic parameters, acrosome reaction, mitochondrial membrane potential, and DNA integrity. Kinematic and trajectory patterns were used to identify fertility-related subpopulations: the rapid, straighter, progressive, nonsinuous pattern (PN) and the transitional, sinuous pattern (TS). In contrast to the conventional notion that the fertilizing spermatozoon is always vigorously motile and more linear, our results demonstrate that sinuous patterns are associated with fertility and correspond to truly functional spermatozoa as supported by more live births produced from predominant TS than PN subpopulation in the inseminate. Our findings ascertain the true practical application significance of microfluidic sorting of functional sperm characterized by sinuous trajectories that can serve as a behavioral sperm phenotype marker for fertility potential. More broadly, we foresee the clinical application of this sorting technology to assisted reproduction in humans.

Review: Sperm-oocyte interactions and their implications for bull fertility, with emphasis on the ubiquitin-proteasome system

Fertilization is an intricate cascade of events that irreversibly alter the participating male and female gamete and ultimately lead to the union of paternal and maternal genomes in the zygote. Fertilization starts with sperm capacitation within the oviductal sperm reservoir, followed by gamete recognition, sperm-zona pellucida interactions and sperm-oolemma adhesion and fusion, followed by sperm incorporation, oocyte activation, pronuclear development and embryo cleavage. At fertilization, bull spermatozoon loses its acrosome and plasma membrane components and contributes chromosomes, centriole, perinuclear theca proteins and regulatory RNAs to the zygote. While also incorporated in oocyte cytoplasm, structures of the sperm tail, including mitochondrial sheath, axoneme, fibrous sheath and outer dense fibers are degraded and recycled. The ability of some of these sperm contributed components to give rise to functional zygotic structures and properly induce embryonic development may vary between bulls, bearing on their reproductive performance, and on the fitness, health, fertility and production traits of their offspring. Proper functioning, recycling and remodeling of gamete structures at fertilization is aided by the ubiquitin-proteasome system (UPS), the universal substrate-specific protein recycling pathway present in bovine and other mammalian oocytes and spermatozoa. This review is focused on the aspects of UPS relevant to bovine fertilization and bull fertility.

Identification of genomic variants causing sperm abnormalities and reduced male fertility

Whole genome sequencing has identified millions of bovine genetic variants; however, there is currently little understanding about which variants affect male fertility. It is imperative that we begin to link detrimental genetic variants to sperm phenotypes via the analysis of semen samples and measurement of fertility for bulls with alternate genotypes. Artificial insemination (AI) bulls provide a useful model system because of extensive fertility records, measured as sire conception rates (SCR). Genetic variants with moderate to large effects on fertility can be identified by sequencing the genomes of fertile and subfertile or infertile sires identified with high or low SCR as adult AI bulls or yearling bulls that failed Breeding Soundness Evaluation. Variants enriched in frequency in the sequences of subfertile/infertile bulls, particularly those likely to result in the loss of protein function or predicted to be severely deleterious to genes involved in sperm protein structure and function, semen quality or sperm morphology can be designed onto genotyping assays for validation of their effects on fertility. High throughput conventional and image-based flow cytometry, proteomics and cell imaging can be used to establish the functional effects of variants on sperm phenotypes. Integrating the genetic, fertility and sperm phenotype data will accelerate biomarker discovery and validation, improve routine semen testing in bull studs and identify new targets for cost-efficient AI dose optimization approaches such as semen nanopurification. This will maximize semen output from genetically superior sires and will increase the fertility of cattle. Better understanding of the relationships between male genotype and sperm phenotype may also yield new diagnostic tools and treatments for human male and idiopathic infertility.

Non-Invasive Approaches to Epigenetic-Based Sperm Selection

Since sperm size and form do not necessarily provide information on internal sperm structures, novel sperm markers need to be found in order to conduct assisted reproductive therapies (ART) successfully. Currently, the priority of andrologists is not only to select those sperm able to fertilize the oocyte, but also a high quality of sperm that will guarantee a healthy embryo. Evidence of this shows us the importance of studying sperm intensively on genetic and epigenetic levels, because these could probably be the cause of a percentage of infertility diagnosed as idiopathic. Thus, more attention is being paid to posttranslational modifications as the key for better understanding of the fertilization process and its impact on embryo and offspring. Advances in the discovery of new sperm markers should go hand in hand with finding appropriate techniques for selecting the healthiest sperm, guaranteeing its non-invasiveness. To date, most sperm selection techniques can be harmful to sperm due to centrifugation or staining procedures. Some methods, such as microfluidic techniques, sperm nanopurifications, and Raman spectroscopy, have the potential to make selection gentle to sperm, tracking small abnormalities undetected by methods currently used. The fact that live cells could be analyzed without harmful effects creates the expectation of using them routinely in ART. In this review, we focus on the combination of sperm epigenetic status (modifications) as quality markers, with non-invasive sperm selection methods as novel approaches to improve ART outcomes.

In vitro exposure of bull sperm cells to DMSA-coated maghemite nanoparticles does not affect cell functionality or structure

Magnetic nanoparticles can be used in different areas of biology. It is therefore important to know the effects of such nanomaterials on germline cells as they may traverse the blood-testis barrier. This work aimed to evaluate the response of bull sperm after exposure to a magnetic fluid containing DMSA-coated maghemite nanoparticles (MNP-DMSA) in order to determine nanotoxicity. Bull sperm was incubated with MNP-DMSA at final concentrations of 0.06, 0.03 or 0.015 mg Fe/mL. Sperm kinetics, plasma membrane integrity and acrosome reaction were evaluated over a 4 h incubation period. The sperm cells were also evaluated by transmission electron microscopy. Exposure of bull sperm to MNP-DMSA did not affect sperm kinetics or integrity. Neither ultrastructural damage of sperm cells nor uptake of nanoparticles by the spermatozoa was observed. In conclusion, MNP-DMSA does not affect sperm function or structure under the conditions tested.

Novel agents for sperm purification, sorting, and imaging

The stringent selection of viable spermatozoa ensures the transmission of high-quality genetic material to the egg during fertilization. Sperm heterogeneity within or between ejaculates and between males obliges varied post-collection handling of semen to assure satisfactory fertility rates. The current techniques used to assess sperm generally detect non-viable and non-fertilizing gametes in the ejaculate, but do not permit the investigation of semen for improved fertility outcomes. Advances in technology, however, have spurred the search for new approaches to enrich semen with high-quality spermatozoa and to track intra-uterine sperm migration. This review highlights the current and future methodologies used for sperm labeling, selection, tracking, and imaging, with specific emphasis on the recent influence of nanotechnology.

Current and future prospects for nanotechnology in animal production

Nanoparticles have been used as diagnostic and therapeutic agents in the human medical field for quite some time, though their application in veterinary medicine and animal production is still relatively new. Recently, production demands on the livestock industry have been centered around the use of antibiotics as growth promoters due to growing concern over microbial antibiotic resistance. With many countries reporting increased incidences of antibiotic-resistant bacteria, laws and regulations are being updated to end in-feed antibiotic use in the animal production industry. This sets the need for suitable alternatives to be established for inclusion in feed. Many reports have shown evidence that nanoparticles may be good candidates for animal growth promotion and antimicrobials. The current status and advancements of nanotechnological applications in animal production will be the focus of this review and the emerging roles of nanoparticles for nutrient delivery, biocidal agents, and tools in veterinary medicine and reproduction will be discussed. Additionally, influences on meat, egg, and milk quality will be reviewed.

In vitro addition of docosahexaenoic acid improves the quality of cooled but not frozen-thawed stallion semen

The aim of the present study was to assess the effect of the addition of docosahexaenoic acid (DHA) on the in vitro quality of cooled and frozen-thawed stallion semen. In Experiment 1, semen from 10 stallions was collected (three ejaculates per stallion). Semen was diluted to 100×10⁶ spermatozoa mL^-1 with 0.02mM vitamin E (VE) and 0, 1, 10 or 20ng mL^-1 DHA and frozen. Semen was thawed and total motility (TM), rapid progressive motility (PM), acrosome integrity, membrane fluidity and morphology were assessed. In Experiment 2, semen from three stallions was collected (three ejaculates per stallion) and frozen as in Experiment 1, but VE and DHA were added after thawing. TM and PM were assessed at 30, 60 and 120min and viability, acrosome integrity and membrane fluidity were evaluated at 30min. In Experiment 3, semen from five stallions was collected (one to three ejaculates per stallion), diluted to 20×10⁶ spermatozoa mL^-1 and stored at 4°C. After 1, 24, 48 and 72h, TM, PM, viability, membrane fluidity and lipid peroxidation were assessed. The addition of DHA had no effect on frozen semen (Experiments 1 and 2) but improved TM, PM and membrane fluidity in cooled stallion semen.