Resveratrol is one of the most investigated natural polyphenolic compounds and is contained in more than 70 types of plants and in red wine. The widespread interest in this polyphenol derives from its antioxidant, anti-inflammatory and anti-aging properties. Several studies have established that resveratrol regulates animal reproduction. However, the mechanisms of action and the potential therapeutic effects are still unclear. This review aims to clarify the role of resveratrol in the male and female reproductive functions, with a focus on animals of veterinary interest. In the female, resveratrol has been considered a phytoestrogen due to its capacity to modulate ovarian function and steroidogenesis via sirtuins, SIRT1, in particular. Resveratrol has also been used to enhance aged oocyte quality, and as a gametes cryo-protectant with mainly antioxidant, and anti-apoptotic effects. In the male, resveratrol enhanced testes function and spermatogenesis through activation of AMPK pathway. Furthermore, resveratrol has been supplemented to semen extenders improving the preservation of sperm quality. In conclusion, resveratrol has potentially beneficial effects for ameliorating ovarian and testes function. However, due to unclear data, further studies are necessary to consolidate these findings.

Redox regulation and oxidative stress have become areas of major interest in spermatology. Alteration of redox homeostasis is recognized as a significant cause of male factor infertility and is behind the damage that spermatozoa experience after freezing and thawing or conservation in a liquid state. While for a long time, oxidative stress was just considered an overproduction of ROS, nowadays it is considered as a consequence of redox deregulation. Many essential aspects of spermatozoa functionality are redox regulated, with reversible oxidation of thiols in cysteine residues of key proteins acting as an “on-off” switch controlling spermatic function. However, if deregulation occurs, these residues may experience irreversible oxidation and oxidative stress leading to spermatic malfunction and ultimately death. Stallion spermatozoa are “professional producers” of ROS due to their intense mitochondrial activity, and thus sophisticated systems to control redox homeostasis are also characteristic of this species. As a result, combined with the fact that embryos can easily be collected in this species, horses are a good model for the study of redox biology in the spermatozoa and its impact on the embryo.

According to global data, there is a male reproductive potential decrease. Pathogenesis of male infertility often is associated with autoimmunity towards sperm antigens essential for fertilization. Antisperm autoantibodies (ASAs) have immobilizing and cytotoxic properties, impairing spermatogenesis, causing sperm agglutination, altering spermatozoa motility and acrosomal reaction, thus preventing ovum fertilization. Infertility diagnosis requires mandatory check for the ASAs. The concept of blood-testis barrier currently is re-formulated with emphasis of informational paracrine and juxtacrine effects, rather than simple anatomical separation. Aetiology of male infertility includes both autoimmune and non-autoimmune diseases, but equally develops through autoimmune links of pathogenesis. Varicocele commonly leads to infertility due to testicular ischemic damage, venous stasis, local hyperthermia, and hypoandrogenism. However, varicocelectomy can alter blood-testis barrier facilitating ASAs production as well. There are contradictory data on the role of ASAs in pathogenesis of varicocele-related infertility. Infection and inflammation both promote ASAs production due to “danger concept” mechanisms and because of antigen mimicry. Systemic pro-autoimmune influences like hyperprolactinemia, hypoandrogenism and hypothyroidism also facilitate ASAs production. Diagnostic value of various ASAs was not yet clearly attributed, and their cut-levels not agreed neither in sera nor in ejaculate. The assessment of the autoimmunity role in pathogenesis of male infertility is ambiguous.

Recently, a rising use of wireless internet technologies has been demonstrated. The devices which use these technologies emit a considerable amount of electromagnetic radiation (EMFs) which could interact with the male reproductive system. The aim of this study was to investigate in vitro influence of electromagnetic fields a 27 GHz on sperm quality in Mytilus galloprovincialis. The experiments were conducted with a no commercial high gain pyramidal horn antenna. Sperm samples, taken from sexually mature males of M. galloprovincialis, were placed in seawater. Once evaluated the number and quality of spermatozoa, sperm cells were exposed to electromagnetic fields. The effect of exposure was evaluated after 10, 20, 30 and 40 minutes with light microscope and using Eosin test. All the samples were performed in triplicate and statistical analysis was carried out by one-way ANOVA test. A significative decrease (30%) in sperm motility was ob-served after 10 minutes of exposure and after 30 minutes all sperms were immobile and not vital. The measurement of the Oxidation Reduction Potential (sORP), which evaluates the oxidative damage on spermatozoa, shows how the exposure to 27 GHz has increased the oxidant amount compared to the control groups. This study provides useful data on potential ecological impact of the EMFs on aquatic animals, that currently are poor investigated.

The sperm heads of frozen/thawed horse spermatozoa were injected into ovulated mouse oocytes where they decondensed and formed paternal pronuclei in which the DNA damage has been evaluated. The motile spermatozoa exhibit none or minor level of DNA damage and the xenogenic zygotes cleave to the two-cell embryonic stage with regular nuclei and no micronuclei (MNs). On the other hand, the immotile spermatozoa exhibit typically high levels of DNA damage and blastomeres in two-cell stage embryos contain multiple MNs. Moreover, extremely high sperm DNA damage prevents even the cleavage to the two-cell stage.Keywords: keyword 1; keyword 2; keyword 3 (List three to ten pertinent keywords specific to the article yet reasonably common within the subject discipline.)

During fertilization, the fusion of the spermatozoa with the oocytes causes the release of calcium from the oocyte endoplasmatic reticulum. This, in turn, triggers a series of calcium ion (Ca2+) oscillations, a process known as oocyte activation. The sperm-specific factor responsible for oocyte activation is phospholipase C zeta (PLCζ). Men undergoing intracytoplasmic sperm injection (ICSI) with their spermatozoa lacking PLCζ are incapable of generating Ca2+oscillation, leading to fertilization failure. The immunofluorescence assay is the most used technique to assess the expression and localization of PLCζ and to diagnose patients with reduced/absent ability to activate the oocytes. In these patients, the use of assisted oocyte activation (AOA) technique can help to yield successful ICSI results and shorten the time of pregnancy. However, the production of a stable PLCζ recombinant protein represents a new powerful therapeutic approach to treating individuals with this condition. We aim to conduct a systematic review focusing on the expression, level, and localization of PLCζ, discussing the novel genetic mutation associated with its impairment. In addition, we highlight the benefits of AOA, looking at new and less invasive methods to diagnose and treat cases with PLCζ dysfunction ability.

[Objetive] The objective of the present study was to characterize different sperm subpopulations based on morphometric parameters of frozen-thawed semen in two bovine subspecies using a CASA system. [Methodology] The experiment was carried out at the Costa Rica Institute of Technology from May to December 2023. Spermatozoa from 10 bulls (five animals of each species Bos taurus and Bos indicus) were evaluated after thawing of the semen doses by an ISAS^®v1, computer-assisted sperm analysis (CASA)-Morph system. Sub-populations of head morphometric spermatozoa were characterized using multivariate procedures such as principal components (PCs) analysis and clustering methods (k-means model) [Results] The ejaculate of male exhibits significant heterogeneity and comprises diverse sperm subpopulations with differing morphometric patterns. Three different sperm subpopulations were identified from three PCs: t head size, head shape, and symmetry of the sperm head and the degree to which it was pyriform. The proportions of the different sperm subpopulations varied in the two-bovine subspecies; Bos taurus and Bos indicus. Results indicated that subpopulations SP1, SP2, and SP3 were different for PC criteria and these differences were relevant. The variability in sperm morphometry assessments underscores the need to standardize semen evaluation protocols [Conclusions] These findings highlight the importance of knowing the diversity in sperm morphometry between subspecies to both improve in vitro evaluation tests and to distinguish subspecies.

ProAKAP4, a precursor of AKAP4 (A-kinase anchor protein) found in the flagellum of mammalian and non-mammalian spermatozoa, serves as a structural protein with established correlations to motility parameters across diverse species. This study aimed to determine the proAKAP4 levels evolution in thawed stallion semen over a 3-hour period, examining its correlation with motility descriptors and mitochondrial membrane potential. Utilizing sixteen ejaculates from four French warmblood stallions, the study involved maintaining thawed samples at 37°C for 3 hours, conducting proAKAP4 enzyme-linked immunosorbent assay (ELISA), computer-assisted sperm analysis (CASA), and mitochondrial membrane potential by JC-1 probe and flow cytometry at 0, 1, and 3 hours post-thawing. The findings indicate significant positive correlations (p≤0.05) between proAKAP4 levels and sperm total or progressive motility at all time points analyzed. Spermatozoa velocity descriptors (VAP, VCL, VSL) and spermatozoa lateral head displacement (ALH) display positive correlations (p≤0.05) with ProAKAP4 at the 0-hour post-thawing. ProAKAP4 concentration exhibits no discernible difference between batches with or without cryoprotectant. Notably, proAKAP4 consumption remains insignificant within the initial hour after thawing but becomes significant (p≤0.05) between 1 and 3 hours post-thawing. In summary, proAKAP4 demonstrates positive correlations with total and progressive motility in stallion semen for up to 3 hours after thawing, albeit showing a noticeable decrease starting from the first hour post-thawing, indicating a progressive consumption as a result of spermatozoa motile activity.

Understanding the factors affecting semen quality is important for optimizing male reproductive efficiency. The present study aimed to evaluate the seminal quality associated with breed, age, season, and sperm counting chamber in boar ejaculates. A total of 22 sexually mature and healthy boars from maternal and sire commercial breeds were utilized as semen donors, with an average age (mean ± standard deviation) of 21.0 ± 7.2 months. Boars were housed individually in well-ventilated pens and fed a standard breeder mix. Semen samples were collected from each boar in dry and rainy season. The boars were grouped according to age into three categories: <12 months, 12-24 months, and >24 months. Only ejaculates with at least 75 % morphologically normal sperm and more than 8.5 x 109 total sperm per ejaculate were used. The samples were analyzed using the Computer-Assisted Semen Analysis (CASA) ISAS®v1 system. Results showed that younger boars (<12 months) exhibited higher total and progressive sperm motility and faster swimming patterns compared to older boars. The percentages of total motility and fast spermatozoa were increased by rainy season. The kinematics variables showed significant differences (P<0.05) between sperm counting chambers. Duroc and Landrace breeds presented spermatozoa with greater total motility, while terminal sire line breeds showed accelerated linear progressiveness (P<0.05). Overall, the impact of various factors on seminal and kinematic variables in boar ejaculates, including age, season, genetic breed composition, and sperm counting chamber enables to better understand the semen quality of boar ejaculates. This highlights the importance of optimizing swine reproductive management practices in sexually active boars.