Acrosome Research Articles

Age, sexual abstinence duration, sperm morphology, and motility are predictors of sperm DNA fragmentation.

Sperm DNA fragmentation (SDF) has recently received attention as a cause of male infertility. However, SDF cannot be fully assessed using conventional semen parameter evaluations alone. Therefore, the authors aimed to elucidate the relationship between SDF and sperm parameters via computer-assisted sperm analysis (CASA) to improve treatment strategies in reproductive medicine. This retrospective observational study analyzed the relationship between sperm parameters assessed by CASA and SDF values determined by the TUNEL assay in 359 patients who visited the Mie University Hospital for infertility treatment. The methodology involved semen analyses covering concentration, motility, and morphology, followed by SDF quantification using the flow cytometry. Statistical analysis revealed significant correlations between SDF and various factors, including age, sexual abstinence period, and specific CASA-measured parameters. Notably, lower sperm motility rates and abnormal head dimensions were associated with higher SDF values, indicating that these parameters were predictive of SDF. This study highlights the importance of sperm motility and head morphology as indicators of SDF, suggesting their usefulness in assessing male fertility. These findings demonstrate the efficacy of detailed sperm analysis, potentially increasing the success rate of assisted reproductive technologies by improving sperm selection criteria.

Sperm collection and characteristics analysis of the critically endangered Chinese pangolin (Manis pentadactyla).

The Chinese pangolin (Manis pentadactyla) is a critically endangered species. However, there is a paucity of research on the male reproductive gamete biology of this species. The present study was the first to systematically analyse the sperm characterization of the Chinese pangolin, including semen collection, sperm morphometry and ultrastructure. The semen of five male Chinese pangolins was successfully collected using the electroejaculation method. CASA (computer-assisted sperm analysis) was used to assess semen quality and take images for sperm morphometric analysis. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used for sperm ultrastructure observation. The results showed that the semen of the Chinese pangolin was yellow to pale yellow in colour, viscous, with a fishy odour, and a slightly alkaline pH of between 7.7 and 7.9. The head defects were the main sperm defects; there were 13 kinds of head defects counted in this study. The total sperm length, head length, head width and tail length were 67.62 ± 0.21μm, 10.47 ± 0.06μm, 1.33 ± 0.006μm and 57.16 ± 0.20μm, respectively. SEM observed that the spermatozoa had a rod-shaped head with a distinct apical ridge, which was different from most mammals and similar to that in avians and reptiles. Interestingly, TEM found that the acrosome membrane of the Chinese pangolin had a double membrane structure rather than a multiple bi-lamellar membrane structure as reported by the previous study. Collectively, this study contributes to the development of artificial breeding efforts and assisted reproductive techniques for the Chinese pangolin, as well as providing technical support for research on germplasm conservation of this species.

Comparison of Special Stains for Analysing the Morphology of Sperm: A Cross-sectional Study

Introduction: In India, male infertility constitutes 40% of infertility cases in males, which has become a serious problem in developing countries. Numerous studies and advanced techniques have been identified in assessing sperm morphology. The detection of sperm morphology is a simple and widely accepted method for determining sperm viability. It assists in selecting appropriate treatments for male infertility in assisted reproductive techniques. Infertility issues can arise in healthy males due to altered sperm morphology. Aim: To analyse the morphology of sperm using basic histopathology stains such as Haematoxylin and Eosin (H&E), Giemsa (G), Eosin-Nigrosin (EN), and Papanicolaou (Pap) stains. Materials and Methods: A cross-sectional study was conducted from April 2022 to June 2022 at the Department of Clinical Pathology, Sree Balaji Medical College and Hospital, Chennai, Tamil Nadu, India. Thirty semen samples were collected from healthy males and stained with H&E, Giemsa, Eosin-Nigrosin, and Papanicolaou stains. The results were observed and tabulated based on sperm shape, size, and motility using Kruger’s strict morphology method. A comparison was made to identify the fastest and most cost-effective method among the four stains. Descriptive statistics were used for the comparison. Results: Among the 30 semen samples, H&E and Papanicolaou stain methods were found to be rapid and cost-effective for analysing sperm morphology compared to the other stains (p-value <0.001). The findings included cases of Normozoospermia (18), Oligozoospermia (9), Necrozoospermia (1), and Teratozoospermia (2). In the Papanicolaou stained samples, the mean sperm head length (μm) was 8.92a±0.5, head width (μm) was 4.48a±0.33, head perimeter (μm) was 27.69a±1.85, head area (μm²) was 33.96a±3.74, tail length (μm) was 44.31a±2.02, sperm length (μm) was 53.24a±2.18, with no cytoplasmic droplets greater than half the size of the head and two vacuoles observed. Papanicolaou stain was the least expensive stain (9.50rs) compared to the other stains used for assessing sperm morphology. Conclusion: Papanicolaou stain is a simple and cost-effective method for analysing sperm morphology compared to other special stains. However, EN Stain is used to detect the morphology of live sperm. Sperm morphology assessment is necessary to monitor the causes of male infertility and determine appropriate treatment modalities.

Morphology and morphometry of sperm in Kurdish stallions, a local breed from western Iran.

The present work was designed for a thorough investigation into the sperm morphology and morphometry of Kurdish stallions. The semen samples were collected from 10 Kurdish stallions. Three preparations from each ejaculate were stained with eosin-nigrosin (EN), Diff-Quik (DQ) and Rose Bengal (RB). The area, perimeter, length and width of the sperm head as well as tail length and total sperm length were measured. The parameters ellipticity, elongation, roughness and regularity were calculated. The morphology of sperm was also investigated under scanning and transmission electron microscopes. DQ and RB provided more clarified images for examining sperm structures compared to the EN method. The head length, head width, area and perimeter in EN were significantly higher than those in DQ and RB (p ≤ .05). Furthermore, the difference in head width, head area and head perimeter between DQ and RB was not significant (p ≥ .05). The tail length and total sperm length in all methods were close together (p ≥ .05). The highest percentage of normal sperm was seen in DQ and RB methods (82.55 ± 2.88 and 88.31 ± 5.19) respectively. The highest values for ellipticity, elongation and regularity were found in RB, whereas the highest value for roughness was measured in EN. Tail defects including coiled tails, and folded midpieces were the most frequent. Scanning electron microscope revealed two types of head shapes: heads with round anterior border, and heads with flat anterior border. The results indicated that despite the routine use of EN for morphological assessment of stallion sperm, RB and DQ can be considered for more clarified details of sperm structure including acrosome and midpiece. Furthermore, the Kurdish stallion sperm has morphometric traits in the normal range established for stallions; yet, some traits were larger than those reported for other breeds. It seems that the sperm of the Kurdish stallion has a longer head and tail in comparison with other horse breeds.

Kinematic and Morphometric Assessment of Fresh Semen, before, during and after Mating Period in Brahman Bulls.

The objective of the present study was to determine the effects that the reproductive season has on the motility, kinematics, morphology, and sperm morphometry of Brahman bulls evaluated with a commercial CASA system. The experiment was carried out at the Costa Rica Institute of Technology from March to August 2021. A total of eight Brahman bulls were used. A total of 28 ejaculates were collected in the pre-mating period (PMP), during it (DMP), and after it (AMP) using an electroejaculator. The sperm concentration was measured with the Accuread photometer. The motility was measured using a Spermtrack® counting chamber. The analyses were performed with the CASA-Mot ISAS®v1 system. The morphology was analyzed using a microscope with a negative phase contrast objective. Morphometry was evaluated with the CASA-Morph. The sperm concentration did not present differences between the PMP and AMP; however, it was significantly higher than DMP (p > 0.05). Regarding the progressiveness variables, linearity on forward progression (LIN), straightness (STR), and wobble (WOB) were higher (p < 0.05) DMP. A kinematic principal component analysis grouped all the variables into three factors and an effect on the reproductive period was found (p < 0.05) in the parameters of the head and middle part of the sperm, such as width and perimeter, which were greater in the PMP. The length of the sperm head in the PMP and DMP did not show differences; however, both were larger (p < 0.05) than AMP. The insertion distance of the middle piece of the sperm was significantly greater than DMP. Finally, the PMP contained cells with a larger insertion angle (p < 0.05) than AMP. These findings are important to understand the implications of reproductive status on sperm quality and to consider them in andrological evaluations.

Deep Learning-Based Classification and Segmentation of Sperm Head and Flagellum for Image-Based Flow Cytometry

Deep Learning-Based Classification and Segmentation of Sperm Head and Flagellum for Image-Based Flow Cytometry

Liquid semen storage-induced alteration in the protein composition of turkey (Meleagris gallopavo) spermatozoa

Liquid storage of turkey semen without the loss of fertilizing ability is of practical interest to the poultry industry. However, fertility rates from liquid-stored turkey semen decline within a few hours. A clear cause of the decline in spermatozoa quality remains unidentified. Therefore, the purpose of the present study was to monitor the dynamics of proteomic changes in spermatozoa during 48 h of liquid storage by 2-dimensional difference in-gel electrophoresis coupled with matrix-assisted laser desorption/ionization mass spectrometry. A total of 57 protein spots were differentially expressed between fresh and stored spermatozoa; 42 spots were more and 15 were less abundant after 48 h of semen storage. Raw proteomic data are available via ProteomeXchange with identifier PXD043050. The selected differentially expressed proteins (DEPs) were validated by western blotting and localized in specific spermatozoa structures by immunofluorescence, such as the head (acrosin and tubulin α), midpiece (acrosin, aconitate hydratase 2, and glycerol-3-phosphate dehydrogenase) and tail (tubulin α). Most of the DEPs that changed in response to liquid storage were related to flagellum-dependent cell motility, energy derivation through oxidation of organic compounds and induction of fertilization, suggesting the complexity of the processes leading to the decrease in stored semen quality. The damaging effect of liquid storage on spermatozoa flagellum manifested as more microtubule proteins, such as tubulins and tektins, most likely formed by posttranslational modifications, tubulin α relocation from the tail to the sperm head, which appeared after 48 h of semen storage, and decreases in fibrous shelf proteins at the same time. Motility could be affected by dysregulation of Ca2+-binding proteins and disturbances in energy metabolism in spermatozoa flagellum. Regarding sperm mitochondria, DEPs involved in energy derivation through the oxidation of organic compounds indicated disturbances in fatty acid beta oxidation and the tricarboxylic acid cycle as possible reasons for energy deficiency during liquid storage. Disturbances in acrosin and 1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase zeta may be involved in rapid declines in the fertility potential of stored turkey spermatozoa. These results showed the complexity of the processes leading to a decrease in stored semen quality and broadened knowledge of the detrimental effects of liquid storage on turkey spermatozoa physiology.

Spermatozoa in mice lacking the nucleoporin NUP210L show defects in head shape and motility but not in nuclear compaction or histone replacement.

Biallelic loss-of-function mutation of NUP210L, encoding a testis-specific nucleoporin, has been reported in an infertile man whose spermatozoa show uncondensed heads and histone retention. Mice with a homozygous transgene intronic insertion in Nup210l were infertile but spermatozoa had condensed heads. Expression from this insertion allele is undefined, however, and residual NUP210L production could underlie the milder phenotype. To resolve this issue, we have created Nup210lem1Mjmm , a null allele of Nup210l, in the mouse. Nup210lem1Mjmm homozygotes show uniform mild anomalies of sperm head morphology and decreased motility, but nuclear compaction and histone removal appear unaffected. Thus, our mouse model does not support that NUP210L loss alone blocks spermatid nuclear compaction. Re-analyzing the patient's exome data, we identified a rare, potentially pathogenic, heterozygous variant in nucleoporin gene NUP153 (p.Pro485Leu), and showed that, in mouse and human, NUP210L and NUP153 colocalize at the caudal nuclear pole in elongating spermatids and spermatozoa. Unexpectedly, in round spermatids, NUP210L and NUP153 localisation differs between mouse (nucleoplasm) and human (nuclear periphery). Our data suggest two explanations for the increased phenotypic severity associated with NUP210L loss in human compared to mouse: a genetic variant in human NUP153 (p.Pro485Leu), and inter-species divergence in nuclear pore function in round spermatids.

Effects of 4G mobile phone radiation exposure on reproductive, hepatic, renal, and hematological parameters of male Wistar rat.

Mobile phones have become a vital part of human life. Due to drastic increase in the number of mobile phone subscribers, exposure to radiofrequency radiation (RFR) emitted from these phones has increased dramatically. Hence, the effect of RFR on humans is an area of concern. This study was performed to determine the impact of 4G mobile phone radiation on the male reproductive system, liver, kidney, and hematological parameters. Seventy-day-old Wistar rats were exposed to 4G radiation (2350MHz for 2h/day for 56days). Sperm parameters such as sperm count, viability, sperm head morphology, mitochondrial activity, total antioxidant activity, and lipid peroxidation of sperm were evaluated. Histopathology of the testis, prostate, epididymis, seminal vesicle, liver, and kidney was carried out. Complete blood count, liver and kidney function tests, and testosterone hormone analysis were done. At the end of the experiment, results showed a significant (p < 0.05) decrease in sperm viability with alterations in the histology of the liver, kidney, testis, and other reproductive organs in the exposed group of rats. A reduced level of testosterone, total antioxidant capacity, and decreased sperm mitochondrial function were also observed in the exposed rats. Moreover, the exposed rats showed an increase in sperm lipid peroxidation and sperm abnormality. Hematological parameters like hemoglobin, red blood cells (RBC), and packed cell volume (PCV) showed a significant (p < 0.05) increase in the exposed rats. The results indicate that chronic exposure to 4G radiation may affect the male reproductive system, hematological system, liver, and kidney of rats.

Human sperm heads harbor modified YsRNA as transgenerationally inherited non-coding RNAs.

Most epigenetic information is reprogrammed during gametogenesis and early development. However, some epigenetic information persists and can be inherited, a phenomenon that is common in plants. On the other hand, there are increasing examples of epigenetic inheritance in metazoans, especially for small non-coding RNAs. The presence of regulatory important RNAs in oocytes is undisputed, whereas the corresponding RNA payload in spermatozoa and its regulatory influence in the zygote and early embryogenesis is largely enigmatic. For humans, we herein describe small YRNA fragments (YsRNA) as a paternal contribution to the zygote. First, we trace the biogenesis of these YsRNAs from the source YRNAs with respect to the 5' and 3' modifications. Both the length and modifications make these YsRNAs reminiscent of canonical piRNAs that are not derived from piRNA clusters. Second, from the early stages of spermatogenesis to maturation in the epididymis, we observe distinct YsRNA profile dynamics in the male germline. We detected YsRNAs exclusively in mature sperm heads, the precursor of the male pronucleus in the zygote, suggesting an important role of the epididymis as a site for transmitting and modification of epigenetic information in the form of YsRNA between soma and germline in humans. Since this YsRNA-based epigenetic mechanism is effective across generations, we wondered whether this phenomenon of epigenetic inheritance has an adaptive value. Full-length YRNAs bind to Ro60, an RNA chaperone that additionally binds to non-coding RNAs. We described the profiles of non-coding RNAs bound to Ro60 in the human sperm head and detected specific binding profiles of RNA to Ro60 but no YRNA bound to Ro60. We hypothesize that the sperm head Ro60 system is functional. An adaptive phenotype mediated by the presence of a large amount of YsRNA in the sperm head, and thus as a paternal contribution in the zygote, might be related to an association of YsRNA with YRNA that prevents the adoption of a YRNA secondary structure capable of binding to Ro60. We hypothesize that preventing YRNAs from acting as Ro60-associated gatekeepers for misfolded RNAs in the zygote and early development may enhance RNA chaperoning and, thus, represent the adaptive molecular phenotype.

ARRDC5 deficiency impairs spermatogenesis by affecting SUN5 and NDC1.

Sperm with normal morphology and motility are essential for successful fertilization, and the strong attachment of the sperm head-tail coupling apparatus to the nuclear envelope during spermatogenesis is required to ensure the integrity of sperm for capacitation and fertilization. Here, we report that Arrdc5 is associated with spermatogenesis. The Arrdc5-knockout mouse model showed male infertility characterized by high bent-head rate and reduced motility in sperm, which led to capacitation defects and subsequent fertilization failure. Through mass spectrometry, we found that ARRDC5 affects spermatogenesis by affecting NDC1 and SUN5. We further found that ARRDC5 might affect the vesicle-trafficking protein SEC22A-mediated transport and localization of NDC1, SUN5, and other head-tail coupling apparatus-related proteins that are responsible for initiating the attachment of the sperm head and tail. We finally performed intracytoplasmic sperm injection as a way to explore therapeutic strategies. Our findings demonstrate the essential role and the underlying molecular mechanism of ARRDC5 in anchoring the sperm head to the tail during spermatogenesis.

173 Effects of aggregated protein content in sperm head on pre-implantation development of bovine embryos

173 Effects of aggregated protein content in sperm head on pre-implantation development of bovine embryos

29 Increase of genomic inbreeding at chromosome level affects differently the sperm head morphometrics shape in frozen–thawed stallion sperm

29 Increase of genomic inbreeding at chromosome level affects differently the sperm head morphometrics shape in frozen–thawed stallion sperm

Phenylbutyrate and Dichloroacetate Enhance the Liquid-Stored Boar Sperm Quality via PDK1 and PDK3

Artificial insemination (AI) with liquid-stored semen is the most prevalent and efficient assisted reproduction technique in the modern pork industry. Pyruvate dehydrogenase complex component X (PDHX) was demonstrated to be associated with sperm metabolism and affected the boar sperm viability, motility, and fertility. Pyruvate Dehydrogenase Kinases (PDKs) are the key metabolic enzymes that regulate pyruvate dehydrogenase complex (PDHC) activity and also the conversion from glycolysis to oxidative phosphorylation. In the present study, two PDK inhibitors, Dichloroacetate (DCA) and Phenylbutyrate (4-PBA), were added to an extender and investigated to determine their regulatory roles in liquid-stored boar sperm at 17 °C. The results indicated that PDK1 and PDK3 were predominantly located at the head and flagella of the boar sperm. The addition of 2 mM DCA and 0.5 mM 4-PBA significantly enhanced the sperm motility, plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), and ATP content. In addition, DCA and 4-PBA exerted their effects by inhibiting PDK1 and PDK3, respectively. In conclusion, DCA and 4-PBA were found to regulate the boar sperm metabolic activities via PDK1 and PDK3. These both can improve the quality parameters of liquid-stored boar sperm, which will help to improve and optimize liquid-stored boar semen after their addition in the extender.

Protective role of eugenol against diabetes-induced oxidative stress, DNA damage, and apoptosis in rat testes.

Diabetes mellitus, a metabolic disorder alters gonadal development and spermatogenesis,reactive oxygenspecies production, DNA damage, and apoptosis, which subsequently lead to male subfertility. Eugenol is an antioxidant, traditionally used as medication for digestive disorders and antioxidant therapy, decrease transport of glucose from GIT to systemic circulation. This experiment was aimed to decipher cellular and molecular insights of eugenol in protecting diabetic germ cells in rats. Rats were assigned randomly into five groups: control, eugenol control (Eugenol 400; EUG), diabetic (DIA), diabetic + eugenol 100 (DIA + EUG 100), and diabetic + eugenol 400 (DIA + EUG 400). EUG 400 and DIA + EUG 400 groups received 400 mg/kg eugenol orally. DIA + EUG 100 group received 100 mg/kg eugenol. Treatment was conducted for 4 weeks. Type 1 diabetes was induced by injecting a single i.p. dose of streptozotocin (55 mg/kg). Morphometric, biochemical, sperm parameters, oxidative stress, hormonal levels, histopathology, and fibrosis in the testis and epididymis, were evaluated. DNA damage was evaluated using halo and comet assays; DNA fragmentation and apoptosis using TUNEL assay. Eugenol treatment significantly normalized biochemical parameters, reduced MDA while increased albumin and GSH levels in diabetes. Eugenol significantly increased sperm numbers, motility and attenuated abnormal sperm head morphology in diabetes. Moreover, eugenol significantly reversed diabetes-induced cellular damages, altered spermatogenesis, and collagen deposition in testis and epididymis. It also significantly attenuated diabetes-associated DNA breaks and apoptosis. These findings suggest that 4 weeks treatment with 400 mg/kg of eugenol could be beneficial for diabetic patients to prevent subfertility.

Normal sperm head morphometric reference values in fertile Asian males.

Sperm head morphology is crucial for male factor infertility diagnosis and assessment of male reproductive potential. Several criteria are available to analyze sperm head morphology, but they are limited by poor methodology comparability and population applicability. This study aimed to explore comprehensive and new normal morphometric reference values for spermatozoa heads in fertile Asian males. An automated sperm morphology analysis system captured 23 152 stained spermatozoa from confirmed fertile males. Of these samples, 1856 sperm head images were annotated by three experienced laboratory technicians as "normal". We employed 14 novel morphometric features to describe sperm head size (head length, head width, length/width ratio, and girth), shape (ellipse intersection over union, girth intersection over union, short-axis symmetry, and long-axis symmetry), area (head, acrosome, postacrosomal areas, and acrosome area ratio), and degrees of acrosome and nuclear uniformity. This straight-forward method for the morphometric analysis of sperm by accurate visual measurements is clinically applicable. The measured parameters present valuable information to establish morphometric reference intervals for normal sperm heads in fertile Asian males. The presented detailed measurement data will be valuable for interlaboratory comparisons and technician training. In vitro fertilization and andrology laboratory technicians can use these parameters to perform objective morphology evaluation when assessing male fertilization potential.

Revisiting chromatin packaging in mouse sperm.

Mammalian sperm show an unusual and heavily compacted genomic packaging state. In addition to its role in organizing the compact and hydrodynamic sperm head, it has been proposed that sperm chromatin architecture helps to program gene expression in the early embryo. Scores of genome-wide surveys in sperm have reported patterns of chromatin accessibility, nucleosome localization, histone modification, and chromosome folding. Here, we revisit these studies in light of recent reports that sperm obtained from the mouse epididymis are contaminated with low levels of cell-free chromatin. In the absence of proper sperm lysis, we readily recapitulate multiple prominent genome-wide surveys of sperm chromatin, suggesting that these profiles primarily reflect contaminating cell-free chromatin. Removal of cell-free DNA, and appropriate lysis conditions, are together required to reveal a sperm chromatin state distinct from most previous reports. Using ATAC-seq to explore relatively accessible genomic loci, we identify a landscape of open loci associated with early development and transcriptional control. Histone modification and chromosome folding profiles also strongly support the hypothesis that prior studies suffer from contamination, but technical challenges associated with reliably preserving the architecture of the compacted sperm head prevent us from confidently assaying true localization patterns for these epigenetic marks. Together, our studies show that our knowledge of chromosome packaging in mammalian sperm remains largely incomplete, and motivate future efforts to more accurately characterize genome organization in mature sperm.

#281 : IVF Outcome of Good Prognosis Patients Based on Sperm Morphology Grading Using Intracytoplasmic Morphologically Selected Sperm Injection (IMSI) Technique

Background and Aims: Spermatozoa morphology is one of the factors that can influence the success of IVF. IMSI is a technique that provides various selection criteria of sperm head’s morphology and the presence of vacuoles with a total magnification of over 6,000. The purpose of this study was to compare the embryo development of good prognosis patients based on sperm morphology grading using IMSI technique. Method: This study was a retrospective analysis performed at Morula IVF Jakarta from 2019 to 2022 based on good prognosis patients (age [Formula: see text] 38 years, AFC [Formula: see text] 7, AMH [Formula: see text] 1.1). There were two groups in this study, (A) sperm grade I and II, (B) sperm grade III and IV, based on Vanderzwalden et al. (2008). The number of patients in group (A) was 1035 patients, and group (B) was 345 patients. The parameters observed in this study were fertilization rate (FR), top embryo quality rate on day 3 (D3) and day 5 (D5), blastocyst rate (BR). Results: The result study showed that (FR) were significantly increased (P=0.000) in group (A) compared to group (B), which was 77.28% and 72.90%. In addition, group (A) had significantly (D3), which was 51.37% (P=0.012) compared to group (B) 46.92%. On the other hand (D5) and (BR) were significantly increased (P=0.000) in group (A), by about 42.58% and 48.01%, contrasted to group (B), which was only 36.11% and 39.21%. Conclusion: Grade I and II sperm of IMSI technique significantly increased IVF outcome in good prognosis patient.

Стан обмінних процесів та відтворна здатність самців кролів за умов теплового стресу

The aim of the work was to study the metabolic processes and reproductive capacity in male rabbits under conditions of heat stress and the action of a complex nanosomal preparation. We have studied the reproductive function in male rabbits under the effects of heat stress and the elimination of its negative effect by feeding a nanosomal drug. We have investigated the changes in biochemical parameters of blood and quality parameters of sperm of male rabbits under the studied factors. It was established that under conditions of heat stress, the pulse rate of rabbits increases by 24.9% (P&lt;0.001), and after the introduction of the nanosomal preparation, it decreases by 10.7% (P&lt;0.05). Heat stress caused changes in the biochemical parameters of the blood of male rabbits, which indicate a stressful state of the body: an increase in the level of glucose by 31.8% (P&lt;0.01), against the background of a decrease in the main metabolic parameters: total protein by 12.5% (P&lt;0.05), cholesterol by 31.4% (P&lt;0.001), testosterone by 41.7% (P&lt;0.001). Feeding the complex nanosomal preparation reduced the signs of body stress and intensified metabolic processes. Under the effects of heat stress, sperm quality indicators of male rabbits decreased: the concentration of sperm by 27.1%, the total number of sperm in the ejaculate by 25.3%, the number of sperm with rectilinear-progressive movement (PMOT) by 6% and the number of degenerated sperm increased by 35.4% (P&lt;0.01). The kinematic parameters of sperm also decreased: the average speed of sperm head advancement along the average trajectory of movement (VAP) by 10.3%; the speed of rectilinear movement of the sperm head along the straight segment between the initial and final points of the trajectory (VSL) by 7.9%; the curvilinear velocity of the sperm head (VCL) by 6.7%. Feeding the complex nanosomal preparation led to an increase in the number of spermatozoa with rectilinear-progressive movement (PMOT) and an increase in the main kinetic indicators (VAP, VSL and VCL) of rabbit spermatozoa under the conditions of heat stress.

Fundamental Mechanisms of Sperm Production: The Role of Microtubules

Spermatogenesis is a feat of unparalleled biological scale and complexity. At any one time, the human testis harbours millions of germ cells in a continuous progression through multiple rounds of mitosis and meiosis, followed by a series of dramatic remodelling events. These processes are the critical determinant of sperm number, morphology, and motility, and 70% of infertile men have abnormalities in one, or more, of these parameters. Testament to its complexity, human spermatogenesis involves the expression of 84% of all protein-encoding genes and is touted as a health ‘canary in the coalmine’, as infertile men as a cohort, die younger than their fertile counterparts. Understanding the mechanisms of sperm production is thus essential, not only in the context of formulating infertility treatments, but also to identify additional health risks for the man and any potential offspring. In addition, sperm research has, and will continue to, shed light on gene function relevant to broad aspects of cell biology, as fertility is often the first, but not the only system, to fail, and may uncover strategies for contraceptive development. Microtubules (MTs) are a key driver of many aspects of sperm production. They form the fundamental machinery of mitosis and meiosis, sperm head shaping, and the sperm tail, in addition to playing roles in intracellular trafficking, including during acrosome biogenesis, and in germ-Sertoli cell adhesion. Through the use of mutant mouse models, our research has revealed the functional diversity of MTs in spermatogenesis is co-ordinated by a diverse suite of MT-associated proteins, including multiple MT-severing proteins from the katanin and spastin families, and the non-canonical tubulins, epsilon and delta. Moreover, we have shown that disruption of this MT regulatory toolbox has catastrophic consequences for sperm production and male fertility.