Causes, effects and molecular mechanisms of testicular heat stress

Assessment of MUSASHI 1 and MUSASHI 2 expression in spermatozoa and testicular tissue

MUSASHI (MSI) family plays the main role in the spermatogenesis process. The purpose of this study was the assessment of sperm MSI1 and MSI2, and sperm functional tests in infertile men (n = 30) with varicocele and fertile men (n = 30). Furthermore, MSI1 and MSI2 proteins were assessed in testicular tissue of azoospermic men (n = 9) as well as epididymal spermatozoa and testis of mice. Expression of MSI1 and MSI2 was assessed at RNA and protein levels in human spermatozoa. Sperm concentration and motility were significantly lower, while abnormal sperm morphology, lipid peroxidation, DNA fragmentation and protamine deficiency were significantly higher in men with varicocele compared to fertile individuals. Any significant difference was not observed in the expression of MSI1 and MSI2 mRNA between the two groups. Unlike MSI1 protein that was not detectable in humans, the relative expression of MSI2 protein was similar in varicocele and fertile individuals. The expression level of both Msi1 and Msi2 proteins was also observable in mouse spermatozoa. No significant relationship was observed between sperm functional parameters with expression of these genes. The data of this study demonstrated that although MSI1 and MSI2 play important roles during spermatogenesis, their relative expression in spermatozoa was not affected by varicocele.

Cellular Therapy via Spermatogonial Stem Cells for Treating Impaired Spermatogenesis, Non-Obstructive Azoospermia

Male infertility is a major health problem affecting about 8–12% of couples worldwide. Spermatogenesis starts in the early fetus and completes after puberty, passing through different stages. Male infertility can result from primary or congenital, acquired, or idiopathic causes. The absence of sperm in semen, or azoospermia, results from non-obstructive causes (pretesticular and testicular), and post-testicular obstructive causes. Several medications such as antihypertensive drugs, antidepressants, chemotherapy, and radiotherapy could lead to impaired spermatogenesis and lead to a non-obstructive azoospermia. Spermatogonial stem cells (SSCs) are the basis for spermatogenesis and fertility in men. SSCs are characterized by their capacity to maintain the self-renewal process and differentiation into spermatozoa throughout the male reproductive life and transmit genetic information to the next generation. SSCs originate from gonocytes in the postnatal testis, which originate from long-lived primordial germ cells during embryonic development. The treatment of infertility in males has a poor prognosis. However, SSCs are viewed as a promising alternative for the regeneration of the impaired or damaged spermatogenesis. SSC transplantation is a promising technique for male infertility treatment and restoration of spermatogenesis in the case of degenerative diseases such as cancer, radiotherapy, and chemotherapy. The process involves isolation of SSCs and cryopreservation from a testicular biopsy before starting cancer treatment, followed by intra-testicular stem cell transplantation. In general, treatment for male infertility, even with SSC transplantation, still has several obstacles. The efficiency of cryopreservation, exclusion of malignant cells contamination in cancer patients, and socio-cultural attitudes remain major challenges to the wider application of SSCs as alternatives. Furthermore, there are limitations in experience and knowledge regarding cryopreservation of SSCs. However, the level of infrastructure or availability of regulatory approval to process and preserve testicular tissue makes them tangible and accurate therapy options for male infertility caused by non-obstructive azoospermia, though in their infancy, at least to date.

Protective Effects of Fisetin in the Mice Induced by Long-Term Scrotal Hyperthermia

Exposure to heat in the male reproductive system can lead to transient periods of partial or complete infertility. The current study aimed to examine the beneficial effects of  Fisetin against spermatogenic disorders in mice affected by long-term scrotal hyperthermia. For this purpose, hyperthermia was induced daily by exposure to the temperature of 43 °C for 20 min for 5 weeks. Except for the Healthy group, six other groups were exposed to heat stress: two treated groups including Preventive and Curative which received oral administration of fisetin (10 mg/kg/day) starting immediately before heat exposure and 15 consecutive days after the end of the heat exposure, respectively. And for each treated group, two groups including Positive Control (Pre/Cur+PC group) and vehicle (Pre/Cur+DMSO group) were considered. Our results showed that the testicular volume; the density of spermatogonia, primary spermatocyte, round spermatid, and Sertoli and Leydig cells; and sperm parameters, as well biochemical properties of the testis tissue, were remarkably higher in both Preventive and Curative groups compared to the other hyperthermia-induced groups and were highest in Preventive ones. Unlike the c-kit gene transcript which was significantly increased in the  Fisetin treatment groups (specially the Preventive group), the expression of HSP72 and NF-kβ genes, Caspase3 protein, and DFI in sperm cells were significantly more decreased in Preventive and Curative groups compared to other hyperthermia-induced groups and were lowest in Preventive ones. Overall,  Fisetin exerts preventive and curative effects against spermatogenic disorders induced by long-term scrotal hyperthermia.

Effect of Wuzi Yanzong Pills on Sertoli cells and blood-testis barrier in heat-stressed rats based on Akt signalling pathway

The blood-testis barrier (BTB) of Sertoli cells (SCs) is an important biological barrier that maintains spermatogenesis and provides a favourable microenvironment for spermatogenesis. However, heat stress can directly damage the BTB structural proteins of testicular SCs, leading to dyszoospermia. Wuzi Yanzong Pills (WYP) is a traditional Chinese medicine formula used to treat male reproductive diseases. However, whether WYP could ameliorate heat stress injury in primary SCs extracted from rat testes and BTB proteins remains unknown. Here, treatment with WYP (low, medium and high dose) increased the SC viability and the proliferation of cell antigen Ki67 significantly. Additionally, it promoted SC maturation, which presented in the form of increased androgen receptors (ARs) and decreased cytokeratin 18 (CK-18) in three WYP dose groups. WYP upregulated BTB proteins such as zonula occludens 1 (ZO-1) and occludin across all WYP groups and decreased phosphorylated Akt (p-Akt) in the middle and high-dose groups; however, ZO-1 and occludin recovery were reduced with the presence of Akt inhibitor in WYP groups. WYP improved SC viability and proliferation, and ameliorated dedifferentiation and BTB-proteins damaged by heat stress via Akt signalling. The findings present theoretical support for the effects of WYP in the management of dyszoospermia and male infertility.

Response to stress in biological disorders: Implications of stress granule assembly and function

It is indispensable for cells to adapt and respond to environmental stresses, in order for organisms to survive. Stress granules (SGs) are condensed membrane‐less organelles dynamically formed in the cytoplasm of eukaryotes cells to cope with diverse intracellular or extracellular stress factors, with features of liquid‐liquid phase separation. They are composed of multiple constituents, including translationally stalled mRNAs, translation initiation factors, RNA‐binding proteins and also non‐RNA‐binding proteins. SG formation is triggered by stress stimuli, viral infection and signal transduction, while aberrant assembly of SGs may contribute to tissue degenerative diseases. Recently, a growing body of evidence has emerged on SG response mechanisms for cells facing high temperatures, oxidative stress and osmotic stress. In this review, we aim to summarize factors affecting SGs assembly, present the impact of SGs on germ cell development and other biological processes. We particularly emphasize the significance of recently reported RNA modifications in SG stress responses. In parallel, we also review all current perspectives on the roles of SGs in male germ cells, with a particular focus on the dynamics of SG assembly.

Integrated study of circRNA, lncRNA, miRNA, and mRNA networks in mediating the effects of testicular heat exposure

The World Health Organization has recognized that testicular function is temperature dependent. Testicular heat exposure caused by occupational factors, lifestyle, and clinical diseases can lead to different degrees of reproductive problems. The aim of this study was to reveal the transcriptional regulatory network and its potential crucial roles in mediating the effects of testicular heat exposure. Testicular tissue was collected from a group of mice subjected to scrotal heat exposure as well as a control group. RNA was isolated from both groups and used for high-throughput sequencing. Using differential transcriptome expression analysis, 172 circRNAs, 279 miRNAs, 465 lncRNAs, and 2721 mRNAs were identified as significantly differentially expressed in mouse testicular tissue after heat exposure compared with the control group. Through Gene Ontology (GO) term and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses, differentially expressed lncRNAs and mRNAs were found to have potentially important functions in meiotic cell cycle (GO:0051321), cytoplasm (GO:0005737), membrane raft (GO:0045121), MAPK signaling (mmu04010), purine metabolism (mmu00230), and homologous recombination (mmu03440). Some of the most upregulated and downregulated lncRNAs and circRNAs were predicted to be associated with numerous miRNAs and mRNAs through competing endogenous RNA regulatory network analysis, which were validated with molecular biology experiments. This research provides high-throughput sequencing data of a testicular heat exposure model and lays the foundation for further study on circRNAs, miRNAs, and lncRNAs that are involved in male reproductive diseases related to elevated testicular temperature.

An effective method for establishing animal models of azoospermia and oligospermia

The current study aims to develop a validated animal model to predict successful spermatogenesis retrieval in azoospermia and oligospermia men. Thirty-two mice were equally divided into 4 groups: control, scrotal hyperthermia (15 times), scrotal hyperthermia group (10 times), scrotal hyperthermia group (5 times). In the scrotal hyperthermia groups, their scrotum exposed to water at a temperature of 43°C for 20 min every other day. Then, the mice were euthanised and sperm samples were collected for sperm parameters analysis, and blood samples were obtained for hormonal assay. The testis samples were taken for histopathology experiments, immunofluorescence staining and Western blot in order to examine the protein expression together with RNA extraction in order to examine the gene expression of germ cell markers. The results of sperm analysis and histopathology of testicular tissue as well as the results of gene expression and Western blot showed that hyperthermia can significantly impair spermatogenesis. In conclusion, we have developed a novel model of azoospermia and oligospermia in mouse, which uses a high temperature to suppress spermatogenesis process through demolition of germ cells subsequent cell cycle arrest and apoptosis. The model will contribute to understanding azoospermia in human, oligospermia pathophysiology and the development of treatment.

Chronic scrotal hyperthermia induces azoospermia and severe damage to testicular tissue in mice

Scrotal hyperthermia leads to altered spermatogenesis due to heat-related oxidative stress. One of the main causes of infertility in men is oxidative stress, which refers to an imbalance in the levels of reactive oxygen species (ROS) and antioxidants. Therefore, this study aimed to evaluate the effects of chronic scrotal hyperthermia on testicular tissue structure, sperm parameters, and oxidative stress in adult mice. Thirty adult NMRI male mice were divided into three groups: Control (n = 10), Sham (n = 10), and Hyperthermia (n = 10). At the end of the study animals were sacrificed for evaluations of biochemical, cellular and histological analysis. The Hyperthermia group revealed a significant reduction in sperm count and weight of testis when compared to the control and sham groups. Also, succinate dehydrogenase (SDH) activity, ROS, ATP production, glutathione disulfide (GSH), tiols metabolism and stereological parameters in the hyperthermia group showed a significant reduction compared to the control and sham groups. Our results also revealed that scrotal hyperthermia significantly increases ROS production, mitochondrial membrane permeability (MMP), malondialdehyde (MDA), oxidized glutathione (GSSG) and apoptotic cells in testicular tissue in the hyperthermia groups in comparison with the control and sham groups. Overall, our result indicated that chronic scrotal hyperthermia causes complete spermatogenic arrest, probably mainly throughout the induction of oxidative stress.

Heat stress response of somatic cells in the testis

The testis is a temperature-sensitive organ that needs to be maintained 2-7 °C below core body temperature to ensure the production of normal sperm. Failure to maintain testicular temperature in mammals impairs spermatogenesis and leads to low sperm counts, poor sperm motility and abnormal sperm morphology in the ejaculate. This review discusses the recent knowledge on the response of testicular somatic cells to heat stress and, specifically, regarding the relevant contributions of heat, germ cell depletion and inflammatory reactions on the functions of Sertoli and Leydig cells. It also outlines mechanisms of testicular thermoregulation, as well as the thermogenic factors that impact testicular function.

Eef2k is not required for fertility in male mice

Background

Eukaryotic elongation factor-2 kinase (Eef2k) is a protein kinase associated with the calmodulin-induced signaling pathway and an atypical alpha-kinase family member. Eef2k-mediated phosphorylation of eukaryotic translation elongation factor 2 (Eef2) can inhibit the functionality of this protein, altering protein translation. Prior work suggests Eef2k to be overexpressed in breast, pancreatic, brain, and lung cancers wherein it may control key processes associated with apoptosis, autophagy, and cell cycle progression. The functional importance of Eef2k in the testes of male mice, however, has yet to be clarified.

Methods

A CRISPR/Cas9 approach was used to generate male Eef2k-knockout mice, which were evaluated for phenotypic changes in epididymal or testicular tissues through histological and immunofluorescent staining assays. In addition, TUNEL staining was conducted to assess the apoptotic death of cells in the testis. Fertility, sperm counts, and sperm motility were further assessed.

Results

Male Eef2k-knockout mice were successfully generated, and exhibited normal fertility and development. No apparent differences were observed with respect to spermatogenesis, sperm counts, or germ cell apoptosis when comparing male Eef2k ^-/- and Eef2k ^+/+ mice.

Conclusions

Male Eef2k-knockout mice remained fertile and were free of any evident developmental or spermatogenic abnormalities, suggesting Eef2k to be dispensable in the context of male fertility.

Understanding how environmental factors influence reproductive aspects of wild myomorphic and hystricomorphic rodents

Myomorphic and hystricomorphic rodents are vital for maintaining various ecosystems around the planet. This review enables a better understanding of how these rodents respond to environmental factors and adapt to climate adversities. Innumerable factors, such as photoperiod, rainfall, and temperature, can impair or contribute to the quality of rodent reproductive parameters. Prolonged animal exposure to high ambient temperatures alters thermoregulation mechanisms and causes testicular and ovarian tissue degeneration and hormonal deregulation. Photoperiod influences the biological circannual rhythm and reproductive cycles of rodents because it strongly regulates melatonin secretion by the pineal gland, which modulates gonadotropic hormone secretion. Rainfall quantity directly regulates the abundance of fruits in an ecosystem, which modulates the reproductive seasonality of species which are most dependent on a seasonal fruit-based diet. Species with a more diversified fruit diet have smaller reproductive seasonality. As such, habitats are chosen by animals for various reasons, including the availability of food, sexual partners, intra-and inter-specific competition, and predation. This knowledge allows us to monitor and establish management plans to aid in conservation strategies for wild rodent species.

Differential abundances of AQP3 and AQP5 in reproductive tissues from dogs with and without cryptorchidism

Aquaporins (AQPs) are integral transmembrane proteins facilitating transport of water and small solutes, such as glycerol and urea, between cells. In male reproductive tracts, AQPs maintain a milieu conducive for sperm formation, maturation, and storage. The aim of this study was to clarify effects of testicular and epidydimal function on male fertility by investigating localisation and abundances of AQP3 and AQP5 in testes and epididymal segments from dogs with and without unilateral cryptorchidism. Immunohistochemistry results indicated AQP3 and AQP5 have different distribution patterns in reproductive tissues of dogs with and without unilateral cryptorchidism. The AQP3, an aquaglyceroprotein, is present in different germ and Sertoli cells in testis of dogs without cryptorchidism. The AQP5 protein was not detected in germ cells but was present in Sertoli and Leydig cells and in endothelia of blood vessels. In cryptorchid dogs, AQP3 was detected in early-developing germ and Sertoli cells, and AQP5 had a distribution pattern similar to testes of dogs without cryptorchidism. In the epididymis, AQP3 and AQP5 were localised in epithelial cells of dogs with and without cryptorchidism in a cell-specific manner. The AQP3 and AQP5 protein was in larger abundance in the gonads from dogs with and without cryptorchidism. In contrast, AQP3 and AQP5 abundance increased in each segment of the cryptorchid epididymis, likely as a compensatory mechanism associated with the pathologic condition. These results indicate involvement of AQP3 and AQP5 in spermatogenesis and sperm maturation. Results from the present study indicate dogs are a useful for comparative reproductive biology studies.

Rapid evolution and molecular convergence in cryptorchidism-related genes associated with inherently undescended testes in mammals

BACKGROUND

The mammalian testis is an important male exocrine gland and spermatozoa-producing organ that usually lies in extra-abdominal scrotums to provide a cooler environment for spermatogenesis and sperm storage. Testicles sometimes fail to descend, leading to cryptorchidism. However, certain groups of mammals possess inherently ascrotal testes (i.e. testes that do not descend completely or at all) that have the same physiological functions as completely descended scrotal testes. Although several anatomical and hormonal factors involved in testicular descent have been studied, there is still a paucity of comprehensive research on the genetic mechanisms underlying the evolution of testicular descent in mammals and how mammals with ascrotal testes maintain their reproductive health.

RESULTS

We performed integrative phenotypic and comparative genomic analyses of 380 cryptorchidism-related genes and found that the mammalian ascrotal testes trait is derived from an ancestral scrotal state. Rapidly evolving genes in ascrotal mammals were enriched in the Hedgehog pathway-which regulates Leydig cell differentiation and testosterone secretion-and muscle development. Moreover, some cryptorchidism-related genes in ascrotal mammals had undergone positive selection and contained specific mutations and indels. Genes harboring convergent/parallel amino acid substitutions between ascrotal mammals were enriched in GTPase functions.

CONCLUSIONS

Our results suggest that the scrotal testis is an ancestral state in mammals, and the ascrotal phenotype was derived multiple times in independent lineages. In addition, the adaptive evolution of genes involved in testicular descent and the development of the gubernaculum contributed to the evolution of ascrotal testes. Accurate DNA replication, the proper segregation of genetic material, and appropriate autophagy are the potential mechanisms for maintaining physiological normality during spermatogenesis in ascrotal mammals. Furthermore, the molecular convergence of GTPases is probably a mechanism in the ascrotal testes of different mammals. This study provides novel insights into the evolution of the testis and scrotum in mammals and contributes to a better understanding of the pathogenesis of cryptorchidism in humans.

Time response of rat testicular alterations induced by cryptorchidism and orchiopexy

Cryptorchidism is one of the main risk factors for infertility and testicular cancer. Orchiopexy surgery corrects cryptorchidism effects. Different models of cryptorchidism developed in the rat include surgery. We assessed testicular alterations in rats submitted to surgical cryptorchidism and examined their potential for reversibility at different time points in order to verify time dependency effect(s) on the recovery of the undescended testes. Cryptorchidism was induced in 3-week-old rats. Animals were euthanized 3, 6 or 11 weeks after surgery to evaluate the morphological progression of cryptorchidism-induced germinative epithelial alterations. Other groups underwent orchiopexy 3, 5 or 9 weeks after surgical cryptorchidism, before or after puberty. Animals were euthanized 3 or 8 weeks after orchiopexy. Controls underwent sham surgery at the same time points as the surgical groups. Cryptorchid testes showed decreased weight, germinative epithelial degeneration, apoptosis and vacuolation, corresponding to impairment of spermatogenesis and of Sertoli cells. Some tubules has a Sertoli cell-only pattern and atrophy. The intensity of damage was related to the duration of cryptorchidism. After orchiopexy, spermatogenesis completely recovered only when testicular relocation occurred before puberty and the interval for recovery was extended. These results indicate that age, sexual maturity and extension of germ cell damage were relevant for producing germ cell restoration and normal spermatogenesis. We provide original observations on the time dependency of testicular alterations induced by cryptorchidism and their restoration using morphologic, morphometric and immunohistochemical approaches. It may be useful to study germ cell impairment, progression and recovery in different experimental settings, including exposure to exogenous chemicals.

Adaptogenic potential of royal jelly in reproductive system of heat stress-exposed male rats

Testicular heat stress (HS) can lead to testicular tissue destruction and spermatogenesis disturbances. Royal Jelly (RJ) has been introduced as a potent antioxidant. We investigated the effects of RJ on testicular tissue, oxidative stress and sperm apoptosis in HS-exposed rats. Compared to HS-exposed groups, RJ co-treatment could improve testosterone reduction and histopathological damages. The RJ co-administration decreased MDA level in testicular tissue, while TAC and CAT levels were remarkably increased compared to HS-exposed groups. Moreover, significant higher expression level of Bcl-2 and lower expression levels of P53 and Caspase-3 were seen following RJ co-administration compared to HS-exposed groups. Our data suggest that RJ can effectively ameliorate experimental HS-induced testiculopathies in rats through testicular antioxidant defense system restoration and germ cells apoptosis regulation.

Stress response pathways in the male germ cells and gametes

The unfolded protein response (UPR) is a conserved and essential cellular pathway involved in protein quality control that is activated in response to several cellular stressors such as diseases states, ageing, infection and toxins. The cytosol, endoplasmic reticulum (ER) and mitochondria are continuously exposed to new proteins and in situations of aberrant protein folding; one of three lines of defence may be activated: (i) heat-shock response, (ii) mitochondrial UPR and (iii) ER UPR. These pathways lead to different signal transduction mechanisms that activate or upregulate transcription factors that, in turn, regulate genes that increase the cell's ability to correct the conformation of poorly folded proteins or, ultimately, lead to apoptosis. Despite the recent progress in understanding such biological processes, few studies have focused on the implications of the UPR in male infertility, highlighting the need for a first approach concerning the presence of these components in the male reproductive system. In testis, there is a high rate of protein synthesis, and the UPR mechanisms are well described. However, the presence of these mechanisms in spermatozoa, apparently transcriptionally inactive cells, is contentious, and it is unclear how sperm cells deal with stress. Here, we review current concepts and mechanisms of the UPR and highlight the relevance of these stress response pathways in male fertility, especially the presence and functional activation of those components in male germinal cells and spermatozoa.

Male infertility

It is estimated that infertility affects 8-12% of couples globally, with a male factor being a primary or contributing cause in approximately 50% of couples. Causes of male subfertility vary highly, but can be related to congenital, acquired, or idiopathic factors that impair spermatogenesis. Many health conditions can affect male fertility, which underscores the need for a thorough evaluation of patients to identify treatable or reversible lifestyle factors or medical conditions. Although semen analysis remains the cornerstone for evaluating male infertility, advanced diagnostic tests to investigate sperm quality and function have been developed to improve diagnosis and management. The use of assisted reproductive techniques has also substantially improved the ability of couples with infertility to have biological children. This Seminar aims to provide a comprehensive overview of the assessment and management of men with infertility, along with current controversies and future endeavours.

Post-conception heat exposure increases clinically unobserved pregnancy losses

Evidence of the relationship between temperature during pregnancy and human embryo mortality is limited. Most importantly, the literature lacks causal estimations and studies on early pregnancy losses. Here, we estimate the impact of early pregnancy temperature exposure on the clinically unobserved pregnancy loss rate. We use administrative data of clinically observed pregnancies from more than three decades for Hungary. We apply an empirical approach that allows us to infer the impact of temperature on the clinically unobserved pregnancy loss rate from the estimated effects on the clinically observed conception rate. The results show that exposure to hot temperatures during the first few weeks after the conception week increases the clinically unobserved pregnancy loss rate, whereas exposure to colder temperatures seems to decrease it. Importantly, the temperature-induced changes represent changes in the total number of pregnancy losses rather than a compositional change between clinically observed and clinically unobserved pregnancy losses.

Acetyl-L-Carnitine Induces Autophagy to Promote Mouse Spermatogonia Cell Recovery after Heat Stress Damage

Acetyl-L-carnitine (ALC) is an effective substrate for mitochondrial energy metabolism and is known to prevent neurodegeneration and attenuate heavy metal-induced injury. In this study, we investigated the function of ALC in the recovery of mouse spermatogonia cells (GC-1 cells) after heat stress (HS). The cells were randomly divided into three groups: control group, HS group (incubated at 42°C for 90 min), and HS + ALC group (treatment of 150 μM ALC after incubated at 42°C for 90 min). After heat stress, all of the cells were recovered at 37°C for 6 h. In this study, the content of intracellular lactate dehydrogenase (LDH) in the cell supernatant and the malondialdehyde (MDA) levels, catalase (CAT) levels, and total antioxidant capacity (T-AOC) were significantly increased in the HS group compared to the CON group. In addition, the mitochondrial membrane potential (MMP) was markedly decreased, while the apoptosis rate and the expression of apoptosis-related genes (Bcl-2, Bax, and caspase3) were significantly increased in the HS group compared to the CON group. Furthermore, the number of autophagosomes and the expression of autophagy-related genes (Atg5, Beclin1, and LC3II) and protein levels of p62 were increased, but the expression of LAMP1 was decreased in the HS group compared to the CON group. However, treatment with ALC remarkably improved cell survival and decreased cell oxidative stress. It was unexpected that levels of autophagy were markedly increased in the HS + ALC group compared to the HS group. Taken together, our present study evidenced that ALC could alleviate oxidative stress and improve the level of autophagy to accelerate the recovery of GC-1 cells after heat stress.

Impact of nonionizing electromagnetic radiation on male infertility: an assessment of the mechanism and consequences

PURPOSE

Environment and lifestyle factors are being attributed toward increased instances of male infertility. Rapid technological advancement, results in emission of electromagnetic radiations of different frequency which impacts human both biologically as well as genetically. Devices like cell phone, power line and monitors emit electromagnetic radiation and are a major source of the exposure. Numerous studies describe the detrimental consequence of radiation on physiological parameters of male reproductive system including sperm parameters (morphology, motility, and viability), metabolism and genomic instability. While the thermal and nonthermal interaction of nonionizing radiations with biological tissues can't be ruled out, most studies emphasize the generation of reactive oxygen species. Oxidative stress alters redox equilibrium and disrupts morphology and normal functioning of sperms along with declination of total anti-oxidant capacity.

CONCLUSION

In this paper, we describe a detailed literature review with the intent of analyzing the impact of electromagnetic radiation and understand the consequence on male reproductive system. The underlying mechanism suggesting ROS generation and pathway of action has also been discussed. Additionally, the safety measures while using electronic gadgets and mobile phones has also been presented.

Anything New about Paternal Contribution to Reproductive Outcomes? A Review of the Evidence

Paternal health and behavioral lifestyles affect reproductive and neonatal outcomes and yet the magnitude of these effects remain underestimated. Even though these impacts have been formally recognized as a central aspect of reproductive health, health care services in Europe often neglect the involvement of fathers in their reproductive programs. Following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for systematic reviews, a literature search was carried out to assess the possible impact of paternal health on reproductive outcomes. The comprehensive strategy included cohort studies and meta-analysis available on PubMed, Web of Science, CINAHL, and Google scholar. Cross-referencing of bibliographies of the selected papers ensured wider study capture. Paternal factors were grouped into two categories respectively identified with the terms "Biological Paternal Factors" and "Lifestyle Paternal Factors". Advanced age may impair male fertility and affect early pregnancy stages. Increased body mass index, smoking, alcohol and recreational drugs, all alter seminal fluid parameters. Hazardous alcohol use correlates with low birthweight in pregnancy and harmful behavioral lifestyles have been linked to congenital heart defects, metabolic and neurodevelopmental disorders in the offspring. Measures targeting paternal health and lifestyle within the first 1,000 days' timeframe need to be implemented in couples undergoing reproductive decisions. Health professionals, as well as future fathers, must be aware of the benefits for the offspring associated with correct paternal behaviors. More research is needed to build guidelines and to implement specific programs aiming at reproductive health promotion.

Shade availability on pasture does not affect semen characteristics of Brahman bulls (Bos taurus indicus)

Testicular degeneration by heat is the leading cause of infertility in bulls. Beef cattle are generally farmed under hot and humid conditions, and consequently, the thermotolerance of each breed must be considered in their natural environment. This study aimed to evaluate the reproductive characteristics of Brahman bulls maintained in the grazing system, with or without shadow availability. Ten Brahman bulls aging between 24 and 30 months were allocated in two different paddocks, with or without shadow availability. The heat tolerance test was performed on three non-consecutive typical summer days. The semen samples were collected at four times points in a 14 days interval. The climate conditions were monitored throughout the experiment; and clinical evaluation, testicular consistence and scrotal circumference were measured before every semen collection. In addition, semen was evaluated regarding volume, aspect, turbulence, motility, straight movement, sperm concentration, and morphological exam. The studied Brahman bulls showed a high thermolysis capacity, high heat tolerance, and no differences in semen quality were observed between groups.

Investigating the Role of the microRNA-34/449 Family in Male Infertility: A Critical Analysis and Review of the Literature

There is a great body of evidence suggesting that in both humans and animal models the microRNA-34/449 (miR-34/449) family plays a crucial role for normal testicular functionality as well as for successful spermatogenesis, regulating spermatozoa maturation and functionality. This review and critical analysis aims to summarize the potential mechanisms via which miR-34/449 dysregulation could lead to male infertility. Existing data indicate that miR-34/449 family members regulate ciliogenesis in the efferent ductules epithelium. Upon miR-34/449 dysregulation, ciliogenesis in the efferent ductules is significantly impaired, leading to sperm aggregation and agglutination as well as to defective reabsorption of the seminiferous tubular fluids. These events in turn cause obstruction of the efferent ductules and thus accumulation of the tubular fluids resulting to high hydrostatic pressure into the testis. High hydrostatic pressure progressively leads to testicular dysfunction as well as to spermatogenic failure and finally to male infertility, which could range from severe oligoasthenozoospermia to azoospermia. In addition, miR-34/449 family members act as significant regulators of spermatogenesis with an essential role in controlling expression patterns of several spermatogenesis-related proteins. It is demonstrated that these microRNAs are meiotic specific microRNAs as their expression is relatively higher at the initiation of meiotic divisions during spermatogenesis. Moreover, data indicate that these molecules are essential for proper formation as well as for proper function of spermatozoa per se. MicroRNA-34/449 family seems to exert significant anti-oxidant and anti-apoptotic properties and thus contribute to testicular homeostatic regulation. Considering the clinical significance of these microRNAs, data indicate that the altered expression of the miR-34/449 family members is strongly associated with several aspects of male infertility. Most importantly, miR-34/449 levels in spermatozoa, in testicular tissues as well as in seminal plasma seem to be directly associated with severity of male infertility, indicating that these microRNAs could serve as potential sensitive biomarkers for an accurate individualized differential diagnosis, as well as for the assessment of the severity of male factor infertility. In conclusion, dysregulation of miR-34/449 family detrimentally affects male reproductive potential, impairing both testicular functionality as well as spermatogenesis. Future studies are needed to verify these conclusions.

The Mechanisms Involved in Obesity-Induced Male Infertility

BACKGROUND

Obesity resulted by imbalance between the intake of energy and energy consumption can lead to growth and metabolic disease development in people. Both in obese men and animal models, several studies indicate that obesity leads to male infertility.

OBJECTIVE

This review has discussed some mechanisms involved in obesity-induced male infertility.

METHODS

Online documents were searched through Science Direct, Pubmed, Scopus, and Google Scholar websites dating from 1959 to recognize studies on obesity, kisspeptin, leptin, and infertility.

RESULTS

Obesity induced elevated inflammatory cytokines and oxidative stress can affect male reproductive functions, including spermatogenesis disorders, reduced male fertility power and hormones involved in the hypothalamus-pituitary-gonadal axis.

CONCLUSION

There is significant evidence that obesity resulted in male infertility. Obesity has a negative effect on male reproductive function via several mechanisms such as inflammation and oxidative stress.

Metabolic diseases affect male reproduction and induce signatures in gametes that may compromise the offspring health

The most prevalent diseases worldwide are non-communicable such as obesity and type 2 diabetes. Noteworthy, the prevalence of obesity and type 2 diabetes is expected to steadily increase in the next decades, mostly fueled by bad feeding habits, stress, and sedentarism. The reproductive function of individuals is severely affected by abnormal metabolic environments, both at mechanical and biochemical levels. Along with mechanical dysfunctions, and decreased sperm quality (promoted both directly and indirectly by metabolic abnormalities), several studies have already reported the potentially harmful effects of metabolic disorders in the genetic and epigenetic cargo of spermatozoa, and the epigenetic inheritance of molecular signatures induced by metabolic profile (paternal diet, obesity, and diabetes). The inheritance of epigenetic factors towards the development of metabolic abnormalities means that more people in reproductive age can potentially suffer from these disorders and for longer periods. In its turn, these individuals can also transmit this (epi)genetic information to future generations, creating a vicious cycle. In this review, we collect the reported harmful effects related to acquired metabolic disorders and diet in sperm parameters and male reproductive potential. Besides, we will discuss the novel findings regarding paternal epigenetic inheritance, particularly the ones induced by paternal diet rich in fats, obesity, and type 2 diabetes. We analyze the data attained with in vitro and animal models as well as in long-term transgenerational population studies. Although the findings on this topic are very recent, epigenetic inheritance of metabolic disease has a huge societal impact, which may be crucial to tackle the 'fat epidemic' efficiently.

Ameliorating effects of curcumin-loaded superparamagnetic iron oxide nanoparticles (SPIONs) on the mouse testis exposed to the transient hyperthermia: A molecular and stereological study

BACKGROUND

Testicular hyperthermia can have negative effects on male fertility. Despite reported therapeutic benefits of curcumin, several factors often limit its application such as low water solubility and instable structure. Curcumin-loaded superparamagnetic iron oxide nanoparticles (SPIONs) were designed to solve its limitation of use. In the present study, we evaluated the effect of curcumin-loaded SPIONs on transient testicular hyperthermia in mouse.

MATERIALS AND METHOD

A total of 18 adult male NMRI mice were divided into three groups (n = 6): I. Controls (Cont), II. Scrotal hyperthermia (Hyp), III. Scrotal hyperthermia + curcumin-loaded iron particles (240 μL) (Hyp + Cur). After seventy days, the animals were sacrificed and used for further molecular and stereological evaluations.

RESULTS

Sperm count, motility and viability significantly decreased in group hyp as compared to cont group. Furthermore, Sperm DNA fragmentation and cell apoptosis in testes increased remarkably in group hyp, compared with group cont. Stereological study showed a reduction in number of spermatogenic and Leydig cells, as well as reduced weight and volume of testes in hyp group. Degenerative appearance of testes exposed to hyperthermia was also observed. In addition, higher mRNA expression of inflammatory cytokines (IL1-α, IL6, and TNF-α) was detected in group hyp compared to cont group. However, curcumin-loaded SPIONs alleviated all of the pathologic changes in the Hyp + Cur group compared to the hyp group.

CONCLUSION

Here, we used nanoparticle form of curcumin in testicular hyperthermia model and showed its ameliorating effects on testes damages caused by heat stress, which can be an appropriate method to overcome the problems that limit curcumin application in cases with increased intra testicular temperature.

Sexual selection and sperm diversity in primates

Many aspects of primate sperm physiology and reproductive behavior have been influenced by sexual selection, especially in taxa exposed to sperm competition where females mate with multiple partners. Primate sperm diversity reflects therefore the evolutionary divergences of the different primate species and the impact of a combination of variables exerting selection pressures on sperm form, function, and competition. Thereby, mating systems, life cycle or ecological variables are some of the important factors driving sperm diversity and explaining variation in terms of sperm morphology, parameters or male sexual characters. Here, we address primate sperm diversity through a compilation of all data available in the literature concerning primate sperm parameters and relationships between them. We also review the factors that can influence primate sperm diversity (e.g. mating systems, trade-off between investments in precopulatory and postcopulatory sexual traits, male and female sexual behaviors, seasonality, social constraints, testosterone levels), and discuss also their relevance to our understanding of human reproduction.

Influence of Lifestyle and Environmental Factors on Semen Quality in Ghanaian Men

Introduction

Male infertility is known to contribute about half of all infertility cases. In Ghana, the prevalence of male infertility is higher (15.8%) than in females (11.8%). Sperm quality is associated with the likelihood of pregnancy and known to be the cause of male fertility problems 90% of the time. Exposure to certain environmental factors reduces semen quality in men. The study examined the effects of environmental and lifestyle factors on semen quality in Ghanaian men.

Materials and Methods

This was a cross-sectional study involving 80 apparent healthy adult males in their reproductive age. Participants were males referred to the laboratory (Immunology Unit of the Korle-Bu Teaching Hospital) for semen analysis test and/or culture and sensitivity. Participants were made to fill out a questionnaire which entailed selected environmental factors (accidents or trauma, exposure to chemicals, radiation, and heat) and lifestyle habits (including alcohol consumption, smoking, and whether participants sat more or less than 4 hours per day). Semen samples were then collected by masturbation into sterile containers and analysed in accordance with WHO guidance for semen analysis within 60 minutes after ejaculation and collection.

Results

About 69% of participants had semen pH within the normal range compared to 15% whose pH were lower than 7.2. There was a significantly high number of immotile sperm cells (p value = 0.017) in participants who sat for more than 4 hours as compared to those that sat for less than 4 hours in a day. Active sperm motility and viability showed significant increase (p value = 0.002 and 0.009, respectively) in participants who kept their cell phones in their side pockets. Smoking produced a twofold decrease in sperm count as smokers had a significantly lower sperm count (12.28 ± 10.95 × 10⁶/ml) compared to the smoke-free (23.85 ± 22.14 × 10⁶/ml). For exposure to STDs, no significant differences were recorded among study groups concerning semen quality.

Conclusion

Sperm quality in Ghanaian men is associated with lifestyle habits. Smoking and sitting for long hours influenced sperm motility and count, respectively. Knowledge of the factors that influence sperm quality in this geographical region can contribute to informed decisions on effective management of infertility in Ghanaian men.

Testis and blood-testis barrier in Covid-19 infestation: role of angiotensin-converting enzyme 2 in male infertility

Severe acute respiratory syndrome coronavirus 2 (SARS- CoV-2) that causes COVID-19 infections penetrates body cells by binding to angiotensin-converting enzyme-2 (ACE2) receptors. Evidence shows that SARS-CoV-2 can also affect the urogenital tract. Hence, it should be given serious attention when treating COVID-19-infected male patients of reproductive age group. Other viruses like HIV, mumps, papilloma and Epstein-Barr can induce viral orchitis, germ cell apoptosis, inflammation and germ cell destruction with attending infertility and tumors. The blood-testis barrier (BTB) and blood-epididymis barrier (BEB) are essential physical barricades in the male reproductive tract located between the blood vessel and seminiferous tubules in the testes. Despite the significant role of these barriers in male reproductive function, studies have shown that a wide range of viruses can still penetrate the barriers and induce testicular dysfunctions. Therefore, this mini-review highlights the role of ACE2 receptors in promoting SARS-CoV-2-induced blood-testis/epididymal barrier infiltration and testicular dysfunction.

Factors associated with direct use of laptop on the lap among male university undergraduates in Southwestern Nigeria

Laptop use comes with potential reproductive health risks for men. This study assessed the knowledge of reproductive health hazards and factors associated with direct use of laptop on the lap among male undergraduates of the University of Ibadan, Nigeria. A cross-sectional study conducted among 444 male undergraduates using multi-stage sampling and data collected through a validated questionnaire. Mean age was 21.0 years ± 2.6. Knowledge and perception of reproductive health hazards associated with direct laptop use were fairly good but practice was high. The knowledge of reproductive health hazards associated with direct laptop use on the lap was not associated with use (p = 0.08) and factors influencing use include; influence by colleagues (67.6%), non-availability of laptop cooling pads (42.6%), high cost of cooling pads (39.9%), perception of convenience (41.7%). Interventions on laptop ergonomics awareness and provision of affordable laptop ergonomic products for university students are recommended.

Amelioration of heat stress-induced damage to testes and sperm quality

Heat stress (HS) occurs when temperatures exceed a physiological range, overwhelming compensatory mechanisms. Most mammalian testes are ∼4-5 °C cooler than core body temperature. Systemic HS or localized warming of the testes affects all types of testicular cells, although germ cells are more sensitive than either Sertoli or Leydig cells. Increased testicular temperature has deleterious effects on sperm motility, morphology and fertility, with effects related to extent and duration of the increase. The major consequence of HS on testis is destruction of germ cells by apoptosis, with pachytene spermatocytes, spermatids and epididymal sperm being the most susceptible. In addition to the involvement of various transcription factors, HS triggers production of reactive oxygen species (ROS), which cause apoptosis of germ cells and DNA damage. Effects of HS on testes can be placed in three categories: testicular cells, sperm quality, and ability of sperm to fertilize oocytes and support development. Various substances have been given to animals, or added to semen, in attempts to ameliorate heat stress-induced damage to testes and sperm. They have been divided into various groups according to their composition or activity, as follows: amino acids, antibiotics, antioxidant cocktails, enzyme inhibitors, hormones, minerals, naturally produced substances, phenolic compounds, traditional herbal medicines, and vitamins. Herein, we summarized those substances according to their actions to mitigate HS' three main mechanisms: oxidative stress, germ cell apoptosis, and sperm quality deterioration and testicular damage. The most promising approaches are to use substances that overcome these mechanisms, namely reducing testicular oxidative stress, reducing or preventing apoptosis and promoting recovery of testicular tissue and restoring sperm quality. Although some of these products have considerable promise, further studies are needed to clarify their ability to preserve or restore fertility following HS; these may include more advanced sperm analysis techniques, e.g. sperm epigenome or proteome, or direct assessment of fertilization and development, including in vitro fertilization or breeding data (either natural service or artificial insemination).

Seminal Plasma Analysis of Oxidative Stress in Different Genitourinary Topographical Regions Involved in Reproductive Tract Disorders Associated with Genital Heat Stress

The pathophysiological mechanisms responsible for male subfertility/infertility caused by or complicated by genital heat stress remains unclear in many respects. Because seminal plasma creates the environment for the proper functioning of spermatozoa, in this study, we verified the associations among standard spermiograms, seminal biochemical parameters (neutral alpha-glucosidase, fructose, and citric acid) and oxidative stress markers (total antioxidant capacity, catalase activity, superoxide dismutase activity, and malondialdehyde concentration) in distinct entities associated with male infertility with and without long-time exposure to local hyperthermia. We demonstrated that men exposed to prolonged environmental or clinically recognized local heat stress in adulthood may suffer from dysregulation of seminal antioxidant components, which can be directly associated with epididymal and prostate function. The comparative analysis of the studied parameters showed numerous correlations among all biochemical parameters (particularly neutral alpha-glucosidase) with low standard semen quality in almost all the investigated infertile groups. In light of the data obtained in this originally designed study, we conclude that more attention should be paid to the epididymis and accessory gland function in subfertile and infertile men exposed to genital heat stress, especially in the context of novel treatment algorithms (targeted therapies).

Capsaicin improves sperm quality in rats with experimental varicocele

Capsaicin is the main capsaicinoid in chilli peppers that have numerous biological and pharmaceutical roles in the body such as antioxidant, anti-inflammatory, anticarcinogenic, analgesic, counterirritant and antiarthritic properties. Numerous studies have shown increased oxidative stress in men with varicocele that is caused by dilation of the spermatic vein and increase of testicular temperature. Therefore, we aimed to assess the effect of Capsaicin on sperm parameters in rats with experimental varicocele. At first, we induced varicocele in 30 Wistar rats and, verify varicocele model only in 10 rats by assessment of sperm parameters, oxidative stress, DNA damage and persistent histone after 2 months. Of the remaining 20 varicocelised rats, half of them were treated with 2.5 mg/kg Capsaicin for two months and the other half served as control. Then, sperm tests were assessed, and the results showed that Capsaicin can restore the mean of sperm oxidative stress (38.78 ± 3.75 versus 58.37 ± 4.34; p < .05), sperm concentration (60.14 ± 7.66 versus 34.87 ± 5.78; p < .05) and motility (62.43 ± 3.10 versus 41.22 ± 5.11; p < .05) in varicocelised rats treated with Capsaicin compared to varicocelised rats that were not treat. Therefore, Capsaicin possibly with reduction of oxidative stress level could improve mean of sperm concentration and motility in varicocele condition.

Effect of low-level laser therapy on seminiferous epithelium: a systematic review of in vivo studies

Laser therapy has proved effective in the treatment of different tissue injuries but little is known about its effect on the testis. The aim of this review was to synthesize research on the in vivo effect of low-level laser therapy on the seminiferous epithelium. A search was performed in the PubMed/Medline, Scopus, Web of Science, and LILACS databases. The initial search retrieved 354 references, and five articles that met the eligibility criteria were selected. In general, the studies showed that laser therapy exerted a positive effect on the germ cell population; however, there was considerable variation in the laser parameters, as well as in the experimental models and methods of tissue analysis used. In conclusion, further studies determining the biostimulation parameters of laser therapy in the testis are necessary in order to provide a basis for the possible application of this technique to the restoration of the human seminiferous epithelium and consequent treatment of some male reproductive disorders.

Do seasonal variations in ambient temperature, humidity and daylight duration affect semen parameters? A retrospective analysis over eight years

We aimed to evaluate the possible effects of seasonal variation on semen parameters. We retrospectively analysed the data of 6,116 semen samples collected at a university hospital for eight years. The past ambient temperature, relative humidity and daylight duration records, and birth registry of the province were obtained to examine the relationship of seasonal changes in semen parameters with annual birth rates and environmental factors. The mean age was 33.03 ± 6.86 years. We found a significant difference between months for sperm concentration (p < .0001), total sperm count (p < .0001), progressively motile sperm count (p < .0001) and normal sperm morphology (p = .028). The sperm concentration and total count were significantly lower in July and August compared with December, May and June. The progressively motile sperm count in October was 23.6% less than the value of May. The temperature and temperature-humidity index were negatively correlated with semen parameters. The highest number of births was in the summer. However, no correlation was present between deliveries and the semen concentration regarding months (r_s  = 0.199, p = .083). In conclusion, we observed significant seasonal and monthly differences in sperm concentration, sperm count and progressively motile sperm count. Increased ambient temperature due to seasonal changes may be a detrimental factor for semen parameters.

Effect of transient scrotal hyperthermia on human sperm: an iTRAQ-based proteomic analysis

BACKGROUND

Through this prospective study, we aimed to explore the change of molecular modification after the transient scrotal hyperthermia on human sperm.

METHODS

Ten healthy subjects selected with strict screening criteria underwent testicular warming in a 43 °C water bath for 30 min a day for 10 consecutive days. Semen samples were collected 2 weeks before the first heat treatment and 6 weeks after the first heat treatment. Proteins from the samples were labeled with isobaric tags for relative and absolute quantitation and analyzed by two-dimensional liquid chromatography-tandem mass spectrometry.

RESULTS

In contrast to the control, of the 3446 proteins identified, 61 proteins were deregulated: 28 were up-regulated and 33 were down-regulated. Approximately 95% of the differentially expressed proteins were found to participate in spermatogenesis, fertilization, or other aspects of reproduction. In particular, the expression of sperm motility and energy metabolism-related proteins AKAP4, SPESP1, ODF1, ODF2, GAPDHS, and ACTRT2, validated by western blotting of the proteins obtained from human and mouse samples, tended to be reduced under scrotal hyperthermia.

CONCLUSIONS

The results indicated that the proteins AKAP4, ODF1, ODF2, GAPDHS, SPESP1, and ACTRT2, play an important role in the heat-induced reversible reduction in sperm concentration and motility and have the potential to be the biomarkers and clinical targets for scrotal heat treatment induced male infertility.

Frequent and mild scrotal heat stress in mice epigenetically alters glucose metabolism in the male offspring

Several studies have reported that health problems occur in assisted reproductive technology (ART)-conceived offspring. Recently, investigations have demonstrated that paternal environmental conditions influence offspring health. However, it is unclear whether the factors that cause male infertility per se affect offspring health and contribute to health problems in ART-born children. Scrotal heat stress represents a common cause for oligoasthenozoospermia, and in these cases, in vitro fertilization-embryo transfer (IVF-ET) is typically recommended for those individuals trying to conceive. We exposed C57BL/6J male mice to frequent and mild scrotal heat stress (fmSHS) (39°C for 30 min once weekly for 5 consecutive wk). Sperm was subjected to IVF-ET with oocytes of untreated C57BL/6J females to produce offspring mice. Glucose intolerance and insulin resistance was observed in the male offspring mice derived from fmSHS-exposed fathers. Islets, after evaluation, remained unchanged. Genes involved in glucose metabolism, especially, those in insulin signaling pathways, showed dysregulation in the liver of the fmSHS-derived male offspring. Differentially methylated regions were found in the sperm of fmSHS-exposed mice by whole genome bisulfite sequencing. Interestingly, abnormal methylation of some genes with altered expression in offspring was observed in both the sperm of fmSHS fathers and the liver of their male offspring. Our results suggest that the factors that cause male infertility can affect male offspring health by an epigenetic mechanism.

Coenzyme Q10 ameliorates inflammation, oxidative stress, and testicular histopathology in rats exposed to heat stress

OBJECTIVES

Our work was aimed at investigating the impact and regulatory mechanism of coenzyme Q10 (CoQ10) on exogenous scrotal heat stress (HS)-induced testicular injuries in rats.

METHODS

The rats (n = 32) were assigned into four groups: control, HS control, HS+CoQ10, and CoQ10. To induce HS, rats' testicles were immersed in a water bath at 43°C for 20 min, every other day for 8 weeks. Moreover, treatment with CoQ10 (10 mg/kg) immediately started before inducing HS and continued for 8 weeks.

KEY FINDINGS

HS decreased the activity of the testicular antioxidant system, superoxide dismutase, glutathione peroxidase, and catalase, while the amount of lipid peroxidation (malondialdehyde) was increased. The index of apoptosis and mRNA expression of caspase 3 and Bax were increased, while the mRNA expression levels of Bcl-2, 3β-HSD, and 17β-HSD3 decreased after HS. Exposure to HS decreased the serum testosterone level but increased the activation of pro-inflammatory cytokines (interleukin 1 beta and tumor necrosis factor-alpha). Deleterious effects of HS on the mentioned parameters were reduced when the rats were treated with CoQ10.

CONCLUSIONS

CoQ10 could suppress the degenerative effects following testicular hyperthermia via its antiapoptotic, anti-inflammation, antioxidative, and androgen synthesis effects.

Rubus apetalus (Rosaceae) improves spermatozoa characteristics, antioxidant enzymes and fertility potential in unilateral cryptorchid rats

BACKGROUND

Cryptorchidism (CPT) is an important cause of male infertility. Rubus apetalus is a medicinal plant with a powerful antioxidant potential. We investigated the effects of aqueous and methanolic extracts of R. apetalus on spermatozoa parameters, antioxidant enzymes and fertility potential of rats with experimental unilateral CPT.

METHOD

Normal (n = 15), sham-operated (n = 15) and cryptorchid rats (n = 80; distributed into 16 groups of 5 rats/group) were treated for 2, 4 or 8 weeks with either distilled water (10 ml/kg/day), vitamin E (75 mg/kg/day), aqueous or methanolic extract of R. apetalus (12 and 60 mg/kg). Sex organ weights, spermatozoa parameters, testicular proteins, sex hormones, fertility potential, morphometric characteristics of testis and oxidative stress markers were measured.

RESULTS

CPT significantly (p < 0.05-0.001) decreased testicular and epididymal weights, spermatozoa density, spermatozoa motility, spermatozoa normality, testicular proteins, LH, FSH and testosterone concentrations. In cryptorchid rats, peri-vascular fibrosis significantly increased (p < 0.001), while diameter of the seminiferous tube, germ cell thickness, gestation index and fertility index decreased when compared to control. Additionally, CPT induced oxidative stress by increasing lipid peroxidation and by reducing superoxide dismutase and catalase activities. These alterations were corrected by R. apetalus. For instance, a significantly increase (p < 0.05-0.001) in spermatozoa motility, normality, viability and density after 2, 4 and 8 weeks of treatment was noticed. R. apetalus also increased (p < 0.05-0.001) testicular proteins, gestation index (90-100%) and fertility index (90-100%), compared to the untreated cryptorchid rats.

CONCLUSION

R. apetalus boosts fertility potential in cryptorchid rats and could be considered as a promising alternative agent for the management of infertility associated with CPT.

Heat-induced changes in the expression and localisation of PGC-1α in the mice testis

The functions of mammalian testis are temperature-sensitive. There are various testicular factors, which express in response to heat as a mechanism of defence. PGC-1α and HSP70 have poetical role in the protection from oxidative stress in various tissues, including testis. The expression of PGC-1α and HSP70 has been shown in the testis, and it has also been documented that heat modulates the expression of PGC-1α and HSP70. However, heat-dependent changes in the localisation and expression of PGC-1α have not been investigated so far. Thus, we studied the expression and localisation pattern of PGC-1α in the testis of heat-treated mice along with marker of proliferation (PCNA, GCNA), serum testosterone levels, MDA levels and HSP70. The results showed a significant increase in PGC-1α and HSP70 and MDA levels in the testis of heat-treated mice along with a decrease in PCNA, GCNA and serum testosterone levels. The immunolocalisation study showed intense immunostaining of PGC-1α in the Leydig cell and germ cells of the heat-treated testis, with pronounced damaged in the histoarchitecture. The results showed that increase expression of PGC-1α in germ cells and Leydig cells of testis could be a counter mechanism to cope up with oxidative stress in coordination with HSP70.

Whole-body heat exposure causes developmental stage-specific apoptosis of male germ cells

Humans are occasionally exposed to extreme environmental heat for a prolonged period of time. Here, we investigated testicular responses to whole-body heat exposure by placing mice in a warm chamber. Among the examined tissues, the testis was found to be most susceptible to heat stress. Heat stress induces direct responses within germ cells, such as eukaryotic initiation factor 2α phosphorylation and stress granule (SG) formation. Prolonged heat stress (42°C for 6 hr) also disturbed tissue organization, such as through blood-testis barrier (BTB) leakage. Germ cell apoptosis was induced by heat stress for 6 hr in a cell type- and developmental stage-specific manner. We previously showed that spermatocytes in the early tubular stages (I-VI) form SGs for protection against heat stress. In the mid-tubular stages (VII-VIII), BTB leakage synergistically enhances the adverse effects of heat stress on pachytene spermatocyte apoptosis. In the late tubular stages (IX-XII), SGs are not formed and severe leakage of the BTB does not occur, resulting in mild apoptosis of late-pachytene spermatocytes near meiosis. Our results revealed that multiple stress responses are involved in germ cell damage resulting from prolonged heat stress (42°C for 6 hr).

Heat SHOCK proteins in equine spermatozoa: Expression and correlation to kinetic and environmental parameters

Heat Shock Proteins are chaperones primary involved in the repair of cellular damages induced by temperature. The harmful effect of temperature on the male gonad is well known, on the contrary knowledge on the effects of the environment on semen quality are still insufficient. The aim of this paper was to learn more about the role of HSPs and the environment in modulating the physiology of equine male gonads. We showed a detailed analysis of equine semen characteristic and the expression level of three HSPs (60-70-90) over a one-year period analyzing the effects of temperature and humidity and the correlation among the different variables. We showed also that the interpretation of results depends strongly on the way in which data are assembled and analyzed, therefore we compared results obtained from three different ways of grouping: according to single months, to weather seasons and to mare reproductive periods. Results showed that the expression of the three HSPs is correlated to the environment through temperature and humidity and that it reaches the highest level in the breeding season and in summer. We found also that HSPs expression is correlated to some variables describing the quality of equine semen (concentration) and the kinetic of spermatozoa (total motility-MOT, %, average path velocity -VAP, μm/s- and lateral head displacement -ALH, μm). No correlation was found between HSPs expression and the mitochondrial membrane potential; while viability and HSP90 expression resulted positively correlated. The month-by-month analysis evidenced that in February equine semen has the highest kinetic characteristics (increased linearity -LIN, %-, straightness -STR, % -and average path velocity -VAP, μm/s) with the highest number of motile, progressive motile and rapid cells. These results may have a great impact in the comprehension of functional aspects of the physiology of equine semen and may have potential implications for breeders who want to understand the period (and/or month) of the year in which equine semen reaches the best characteristics with increased chances for better results in reproductive practice.

Heat stress effects on sheep: Are hair sheep more heat resistant?

Climatic variables can trigger physiological, biochemical, haematological and hormonal alterations that influence the maintenance of homeothermy and can affect production and productivity in sheep. Different mechanisms are responsible for tolerance to heat stress (HS) including coat and skin colour, body size, fat distribution, physiological reactions and not just coat type (hair/wool). This review looks at physical, physiological, molecular and genetic aspects of heat tolerance in sheep and how they affect hair and wool sheep. We propose that it is the adaptation to hot environments and not the type of coat (wool/hair) itself that determines the capacity of the resistance of the animal to HS, due to modifications in essential pathways such as energy metabolism, physiological responses and body size. When studied in similar environments, commercial wool breeds tend to show higher heat stress, but hair breeds tend not to differ from wool breeds that are adapted to hot environments.