Scrotal Heat Research Articles

Beneficial effects of pentoxifylline on spermatogenesis and germ cell apoptosis in stallions subjected to scrotal heat stress

Beneficial effects of pentoxifylline on spermatogenesis and germ cell apoptosis in stallions subjected to scrotal heat stress

The Impact of Photobiomodulation Therapy on Enhancing Spermatogenesis and Blood-Testis Barrier Integrity in Adult Male Mice Subjected to Scrotal Hyperthermia.

Introduction: Unhealthy lifestyle choices such as alcohol, chemicals, and heat stress can worsen male infertility. Heat stress can cause damage to the essential structure known as the blood-testis barrier (BTB). Photobiomodulation therapy (PBMT) has been employed in various studies to enhance sperm quality in individuals with genital inflammatory conditions in recent times. The current research sought to study how laser therapy affects spermatogenesis and the structure of the BTB in a mouse model of scrotal heat exposure. Methods: Thirty adult male NMRI mice, 8 weeks old, were divided into three groups: Control, Hyperthermia, and Hyperthermia+Laser 0.03 J/cm2. The animals in the hyperthermia group had their testicles exposed to water at 43 °C for 20 minutes five times every other day. Then, the testicles were exposed to laser radiation every other day for 35 days, lasting 3 minutes each time, with an energy density of 0.03 J/cm2. Animals were sacrificed, and sperm parameters, reactive oxygen species (ROS) and glutathione (GSH) levels, stereological parameters, and gene expression were assessed in the end. Results: The study showed that PBMT can significantly enhance sperm quality, quantity of spermatogenic cells, testicular volume, levels of ROS and GSH, and gene expression related to the blood-testis barrier. Conclusion: Currently, PBMT is a novel approach for addressing male infertility by preserving the integrity of the BTB in Sertoli cells, which in turn supports the growth and specialization of germ cells.

The effects of vitamin C and vitamin B12 on improving spermatogenesis in mice subjected to long-term scrotal heat stress.

Scrotal hyperthermia poses a significant threat to spermatogenesis and fertility in mammalian species. This study investigated the effects of vitamin B12 and vitamin C on spermatogenesis in adult male mice subjected to long-term scrotal hyperthermia. The rationale is based on the sensitivity of germ cells and epididymal sperm to increased scrotal temperatures. While various factors, both internal and external, can raise the testicular temperature, this study focused on the potential therapeutic roles of vitamins B12 and C. After inducing scrotal hyperthermia in mice, vitamin B12 and vitamin C were administered for 35 days. We assessed sperm parameters, serum testosterone levels, stereological parameters, the percentage of apoptotic cells, reactive oxygen species (ROS) levels, and glutathione (GSH) levels. Additionally, real-time polymerase chain reaction was used to analyze the expression of the c-kit, stimulated by retinoic acid gene 8 (Stra8), and proliferating cell nuclear antigen (Pcna) genes. Vitamin C was more effective than vitamin B12 in improving sperm parameters and enhancing stereological parameters. The study showed a significant decrease in apoptotic cells and a beneficial modulation of ROS and GSH levels following vitamin administration. Moreover, both vitamins positively affected the expression levels of the c-kit, Stra8, and Pcna genes. This research deepens our understanding of the combined impact of vitamins B12 and C in mitigating the effects of scrotal hyperthermia, providing insights into potential therapeutic strategies for heat stress-related infertility. The findings highlight the importance of considering vitamin supplementation as a practical approach to counter the detrimental effects of elevated scrotal temperatures on male reproductive health.

The role of the intrinsic pathway of apoptosis in human ejaculated sperm damage under a state of scrotal heat stress

PurposeThe study aimed to determine the associations among standard sperm characteristics and oxidative/apoptotic markers in ejaculated sperm of men exposed to prolonged scrotal hyperthermia of either environmental or clinical origin.MethodsThe original study design included four research groups: professional drivers (n = 54), infertile men with varicocele (n = 78), infertile men not exposed to prolonged genital heat stress (n = 37), and fertile individuals serving as the control group (n = 29). Standard semen analysis was performed according to the 5th WHO laboratory manual. The following oxidative and apoptotic parameters of sperm were investigated: mitochondrial superoxide anion generation (MitoSOX Red dye), phosphatidylserine externalization (Annexin V binding assay), mitochondrial membrane potential (JC-1 dye), DNA fragmentation (TUNEL/PI assay), and membrane fluidity (merocyanine 540 dye).ResultsAll the studied groups presented a strong deterioration in routine sperm parameters and a strongly apoptotic phenotype in sperm, characterized by both decreased mitochondrial membrane potential and enhanced DNA fragmentation, regardless of the thermal insult. Significant induction of mitochondrial superoxide anion generation was noted only in the groups exposed to genital heat stress. A positive correlation between the production of superoxide anion in the mitochondrial chain and the level of DNA fragmentation in drivers was also noted.ConclusionLong-term exposure to scrotal hyperthermia in real-life situations is sufficient to reduce sperm quality in humans. The thermal stress directly induces the oxidative stress cascade in ejaculated sperm, affecting the plasma membrane fluidity, mitochondrial homeostasis, and sperm DNA integrity.

Intratesticular transplantation of allogenic mesenchymal stem cells mitigates testicular destruction after induced heat stress in Miniature-horse stallions

Testicular degeneration (TD) is the most frequent cause of sub or infertility in stallions. Currently, mesenchymal stem cells (MSC) have been studied as a therapeutic option for several diseases including induced-TD in laboratory animals. Therefore, this study aimed to evaluate the effect of intratesticular MSC therapy on the testicular histology of stallions submitted to scrotal heat stress. Ten healthy Miniature-horse stallions were submitted to testicular heat stress induced by a heating wrap device (42-45°C). Afterward, the stallions were divided into two groups and treated seven days later. MSCs-treated stallions were treated with an intratesticular injection of 10 × 106 of MSCs diluted in 5 mL of PBS, whereas placebo-treated stallions had 5 mL of PBS intratesticular injected. All stallions had testicular biopsies collected seven days before and one- and 14-days post-heat stress and were castrated 30 days after testicular insult. Tissue sections were stained with H&E and evaluated for the tubular and luminal diameter, epithelial thickness, seminiferous tubules (STs) integrity, the number of spermatozoa in the STs, and the percent of abnormal STs. Significance was set at P≤0.05. In both groups, testicular heat stress damaged the STs (P<0.05). However, STs’ parameters were improved in MSCs-treated stallions compared to placebo-treated stallions 30 days after the testicular insult (P<0.05). In conclusion, the results of the present study suggest that intratesticular MSC therapy provided a therapeutic advantage in rescuing acute TD in stallions. However, further studies are essential to evaluate the benefits of this therapy on semen parameters and stallions with idiopathic TD.

Gypenosides Production and Spermatogenesis Recovery Potentials of Extracts from Cell Suspension Cultures of Gynostemma pentaphyllum

Background: Gynostemma pentaphyllum (GP), also called Giao-co-lam, is a traditional Vietnamese herb, also known as the "Herb of Immortality", that grows throughout Asian countries and is used for the treatment of hematuria, edema in the pharynx and neck, tumors, and trauma.&#x0D; Methods: In this study, we investigated the effects of culture conditions on cell growth and total gypenoside accumulation in the GP suspension cells. Cells were cultured on Murashige and Skoog (MS) medium supplemented with 2.0 mg/L KIN and 0.5 mg/L IBA, and different inoculum sizes (2-4 g) for 10-24 days.&#x0D; Results: The results showed that the optimum inoculum size and shaking speed were 3 g of callus and 120 rpm, respectively. The highest cell biomass reached was 5.833 g of fresh weight, corresponding to 0.136 g of dry weight after 20 days of culture. The total gypenoside and Rb1 accumulation was the highest after 18 days of culture, with 46.498 mg/g and 0.038 mg/g dry weight, respectively. In addition, the crude extract from GP cell suspension cultures remarkably improved pathological changes in mouse testicular tissue after scrotal heat exposure. Blood testosterone levels were significantly increased in heat-exposed mice treated with the GP cell suspension culture extract.&#x0D; Conclusion: Taken together, these results suggest that GP bio-mass production by cell suspension cultures leads to the accumulation of gypenosides in large amounts, and provides the potential for the recovery of spermatogenesis following heat stress.

5-Aminolevulinic acid combined with ferrous iron ameliorates scrotal heat stress-induced spermatogenic damage by enhancing HO-1 expression

To explore whether 5-Aminolevulinic acid combined with ferrous iron(5-ALA/Fe2+) could protect testicular tissues damage of mice subjected to heat stress (HS) and provide its underlying mechanisms. 5-ALA/Fe2+ was administered intragastrically to mice for 10days, then exposed to a scrotal heat stress at 43°C for 20min on third day. Testes were harvested for morphologic and histopathological examination, oxidative stress, apoptosis, heme oxygenase-1 (HO-1) and inflammation detection. The mitogen-activated protein kinases (MAPK) signaling pathway in testis and CD4+FoxP3+regulatory T (Treg) cells in spleen were also investigated. Compared to control group, the testis weight decreased and histological damage severed in HS group. Besides, HS also increased the oxidative stress, apoptosis and inflammation in testis. However, these indicators were ameliorated after 5-ALA/Fe2+ treatment but deteriorated after receiving ZnPPIX. The expression of HO-1 was increased both in HS group and 5-ALA/Fe2+ group. The protein expression levels of MAPK proteins were activated by HS and inhibited by 5-ALA/Fe2+. The CD4+FoxP3+ Treg generation was reduced by HS and increased by 5-ALA/Fe2+. In this study, we have demonstrated that 5-ALA/Fe2+ ameliorated the spermatogenic damage induced by scrotal heat stress via up-regulating the expression of HO-1 and inhibiting MAPK mediated oxidative stress and apoptosis and inducing CD4+Foxp3+ Tregs to inhibit the inflammation induced by HS in mice.

SERBP1 Promotes Stress Granule Clearance by Regulating 26S Proteasome Activity and G3BP1 Ubiquitination and Protects Male Germ Cells from Thermostimuli Damage.

Stress granules (SGs) are membraneless cytoplasmic condensates that dynamically assemble in response to various stressors and reversibly disassemble after stimulus removal; however, the mechanisms underlying SG dynamics and their physiological roles in germ cell development are elusive. Here, we show that SERBP1 (SERPINE1 mRNA binding protein 1) is a universal SG component and conserved regulator of SG clearance in somatic and male germ cells. SERBP1 interacts with the SG core component G3BP1 and 26S proteasome proteins PSMD10 and PSMA3 and recruits them to SGs. In the absence of SERBP1, reduced 20S proteasome activity, mislocalized valosin containing protein (VCP) and Fas associated factor family member 2 (FAF2), and diminished K63-linked polyubiquitination of G3BP1 during the SG recovery period were observed. Interestingly, the depletion of SERBP1 in testicular cells invivo causes increased germ cell apoptosis upon scrotal heat stress. Accordingly, we propose that a SERBP1-mediated mechanism regulates 26S proteasome activity and G3BP1 ubiquitination to facilitate SG clearance in both somatic and germ cell lines.

165 Epididymal cauda molecular profile is altered by scrotal heat stress

Reproduction, Fertility and Development is an international journal publishing original research , review and comment in the fields of reproduction and developmental biology in humans, domestic animals and wildlife

Testicular heat stress, a historical perspective and two postulates for why male germ cells are heat sensitive.

Herein, we compare the different experimental regimes used to induce testicular heat stress and summarise their impact on sperm production and male fertility. Irrespective of the protocol used, scrotal heat stress causes loss of sperm production. This is first seen 1-2 weeks post heat stress, peaking 4-5 weeks thereafter. The higher the temperature, or the longer the duration of heat, the more pronounced germ cell loss becomes, within extreme cases this leads to azoospermia. The second, and often underappreciated impact of testicular hyperthermia is the production of poor-quality spermatozoa. Typically, those cells that survive hyperthermia develop into morphologically abnormal and poorly motile spermatozoa. While both apoptotic and non-apoptotic pathways are known to contribute to hyperthermic germ cell loss, the mechanisms leading to formation of poor-quality sperm remain unclear. Mechanistically, it is unlikely that testicular hyperthermia affects messenger RNA (mRNA) abundance, as a comparison of four different mammalian studies shows no consistent single gene changes. Using available evidence, we propose two novel models to explain how testicular hyperthermia impairs sperm formation. Our first model suggests aberrant alternative splicing, while the second model proposes a loss of RNA repression. Importantly, neither model requires consistent changes in RNA species.

Chronic scrotal heat stress causes testicular interstitial inflammation and fibrosis: An experimental study in mice.

BackgroundChronic heat stress is a risk factor that adversely affects the reproduction system. Inflammation and fibrosis are 2 important response processes to damaged tissues.ObjectiveThis study investigates the association of chronic scrotal heat stress with testicular interstitial inflammation and fibrosis in mice.Materials and MethodsFor all experiments, 8-10 wk old male Swiss mice (Mus musculus) (20-23 gr) were divided into 3 groups (n = 10/each). The heat-stress groups were submerged in a water bath at 37 C and 40 C, while the control group was treated at 25 C. The testicular tissues underwent hematoxylin and eosin staining, picro sirius red staining, and immunohistochemistry for intercellular adhesion molecule-1, fibroblast-specific protein 1, F4/80, collagen I, and Ki-67 staining to determine the testicular interstitial inflammation and fibrosis.ResultsChronic scrotal heat stress impairs spermatogenesis and reverses testicular histological structure. In this study, heat stress significantly induced increased interstitial cell proliferation and upregulation of intercellular adhesion molecule-1 expression in the interstitial testicular tissue. In the interstitial testicular tissue, the number of F4/80-positive macrophages and the number of fibroblast-specific protein 1-positive fibroblasts were significantly increased in the heat-exposed groups compared to those in the control group. The heat exposed groups had substantially increased extracellular matrix collagen accumulation in their testicular interstitial tissues.ConclusionHeat stress adversely affects the testicular structure and spermatogenesis, causes inflammation, and leads to testicular interstitial fibrosis.

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, whichwere 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.

Changes in miRNA levels of sperm and small extracellular vesicles of seminal plasma are associated with transient scrotal heat stress in bulls

Scrotal heat stress affects spermatogenesis and impairs male fertility by increasing sperm morphological abnormalities, oxidative stress and DNA fragmentation. While sperm morpho-functional changes triggered by scrotal heat stress are well described, sperm molecular alterations remain unknown. Recently, spermatozoa were described as accumulating miRNAs during the last steps of spermatogenesis and through epididymis transit, mainly by communication with small extracellular vesicles (sEVs). Herein, the aim was to investigate the impact of scrotal heat stress in miRNAs profile of sperm, as well as, seminal plasma sEVs. Six Nelore bulls (Bos indicus) were divided into two groups: Control (CON; n = 3) and Scrotal Heat Stress (SHS; n = 3; scrotal heat stressed during 96 h by scrotal bags). The day that the scrotal bags were removed from SHS group was considered as D0 (Day zero). Seminal plasma sEVs were isolated from semen samples collected seven days after heat stress (D+7) to evaluate sEVs diameter, concentration, and 380 miRNA levels. Sperm morpho-functional features and profile of 380 miRNAs were evaluated from semen collected 21 days after heat stress (D+21). As a control, sEVs and sperm were analyzed seven days before heat stress (D-7). Only semen parameters that were not significantly different (P > 0.05) among bulls on D-7 were addressed on D+7 and D+21. While no alterations in diameter and concentration were detected in sEVs on D+7 between CON and SHS groups, three sEVs-miRNAs (miR-23b-5p, −489 and −1248) were down-regulated in SHS bulls compared to CON on D+7; other three (miR-126-5p, −656 and −1307) displayed a tendency (0.05 < P < 0.10) to be altered. Sperm oxidative stress was higher, and the level of 21 sperm miRNAs was altered (18 down-, 3 up-regulated) in SHS bulls compared to CON on D+21. Functional analysis indicated that target genes involved in transcription activation, as well as cell proliferation and differentiation were related to the 18 down-regulated sperm miRNAs (miR-9-5p, −15a, −18a, −20b, −30a-5p, −30b-5p, −30d, −30e-5p −34b, −34c, −106b, -126-5p, −146a, −191, −192, −200b, −335 and −449a). Thus, the scrotal heat stress probably impacted testicular and epididymis functions by reducing the levels of a substantial proportion of sEVs and sperm miRNAs. Our findings suggest that miR-126-5p was possibly trafficked between sEVs and sperm and provide new insights on the mechanism by which sperm acquire miRNAs in the last stages of spermatogenesis and sperm maturation in cattle.

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

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

Saponins derived from the stems and leaves of Panax ginseng attenuate scrotal heat-induced spermatogenic damage via inhibiting the MAPK mediated oxidative stress and apoptosis in mice.

Heat stress (HS) reaction is a stress response caused by adverse conditions. Currently, the incidence of reproductive malignancies particularly in males has been constantly increasing. This work investigated the effects of saponins derived from the stems and leaves of Panax ginseng (GSLS) on testicular injury induced by scrotal hyperthermia in mice. GSLS (150, 300 mg/kg) were administered intragastrically to mice for 14 days, then exposed to a single scrotal heat treatment at 43°C for 18 min on seventh day. HS induced a significant loss of multinucleate giant cells, desquamation of germ cells in destructive seminiferous tubules. Moreover, HS reduced the serum testosterone, testicular tissue superoxide dismutase activity and glutathione (GSH) content, while significantly enhanced the production of malondialdehyde (p < .05). GSLS exhibited the protective potential against HS-induced injury not only by modulating Bcl-2 family and caspase protease family, but also by suppressing the protein levels of heme oxygenase-1 (HO-1), heat shock protein 70 (HSP70), hypoxia inducible factor-1α (HIF-1α) and activation of Mitogen-activated protein kinase (MAPK) signaling pathways (p < .05). In conclusion, we clearly demonstrated that GSLS exhibited a significant protective effect against HS-induced testicular dysfunction, mainly the inhibition of oxidative stress associated apoptosis partly via regulation of the MAPK signaling pathway.

Heat Stress and Pulsed Unfocused Ultrasound: The Viability of these Physical Approaches for Drug Delivery into Testicular Seminiferous Tubules.

To investigate the application of Scrotal Heat Stress (SHS) and Pulsed Unfocused Ultrasound (PuFUS) to explore Blood-Testis Barrier (BTB) permeability in adult mice. The BTB provides a stable microenvironment and a unique immune barrier for spermatogenesis. Meanwhile, it blocks macromolecular substances access, including therapeutic agents and antibodies, thereby it decreases the therapeutic or immunocontraception effects. To determine the viability of these physical approaches in delivering macromolecular substances into seminiferous tubules. Mice were subjected to receive single SHS intervention at 39°C, 41°C, or 43°C for 30 min. Whereas, mice received the PuFUS intervention at 1.75w/cm2, 1.25w/cm2, and 2.5w/cm2 for 2 min, 5 min, and 10 min, respectively. The Biotin and macromolecular substances (IgG, IgM, and exosomes) were separately injected into the testicular interstitium at different times following SHS or PuFUS interventions, to observe their penetration through BTB into seminiferous tubules. As detected by Biotin tracer, the BTB opening started from day-2 following the SHS and lasted for more than three days, whereas the BTB opening started from 1.5h following PuFUS and lasted up to 24h. Apparent penetration of IgG, IgM, and exosomes into seminiferous tubules was observed after five days of the SHS at 43°C, but none at 39°C, or any conditions tested with PuFUS. The current results indicate that SHS at 43°C comparatively has the potential for delivering macromolecular substances into seminiferous tubules, whereas the PuFUS could be a novel, quick, and mild approach to open the BTB. These strategies might be useful for targeted drug delivery into testicular seminiferous tubules. However, further studies are warranted to validate our findings.

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

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

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.

Influence of scrotal heat stress on testicular morphometry, histology and gene expression in stallions treated with pentoxifylline

The New Jersey horse racing industry has declined over the last 5 years as indicated by decreases in the number of racing days, stallions standing, mares bred, and foals registered. These changes were hypothesized to have potential negative consequences for veterinary practices. The objective of the survey was to investigate changes in veterinary practice revenue and staff over a five-year period. Members of the New Jersey Association of Equine Practitioners completed a survey detailing their involvement in the horse racing industry and breeding of racehorses. A response rate of 49% was achieved with 45% of respondents indicating they were involved in the horse racing industry as a veterinarian. Respondents indicated they decreased (44%), did not change (17%), or increased (39%) their number of staff because of changes in the horse racing industry over the past 5 years. In a similar manner, veterinarians reported decreases (48%), no change (22%), or increases (30%) in revenue. Practice revenue from the breeding of racehorses and its associated components either decreased (91%) or did not change (9%) over the past 5 years because of changes in the horse racing industry. Results indicate declines in the horse racing industry had minimal impact on veterinary practices involved in this sector of the industry. Veterinarians and practices involved in racehorse breeding and its associated components, in contrast, were negatively impacted by changes in the horse racing industry.

Frequent and mild scrotal heat stress impairs embryo development, implantation and offspring sex ratio in mice.

Frequent and mild scrotal heat stress (fmSHS) often occurs in humans. The aim of this study was to determine the impact of fmSHS on natural fertility, the IVF-embryo transfer (IVF-ET) process and the offspring sex ratio. Male mice were randomly divided into four groups: no scrotal heat stress (SHS) (controls) and those subjected to SHS at 37°C, 39°C or 41°C for 30min once a week for 5 consecutive weeks. The testis, epididymis and sperm quality were assessed to evaluate the effects of different degrees of SHS, to establish an fmSHS model. Then, natural fertility, IVF-embryo transfer (IVF-ET) results, embryo development, offspring sex ratio and the X/Y chromosome-bearing sperm ratio were examined. SHS at 39°C and 41°C caused mild impairment to spermatozoa, leading to a phenotype similar to oligoasthenozoospermia in humans. Given that most SHS conditions in humans are close to body temperature, SHS of 39°C was adopted to build the fmSHS model. fmSHS reduced the fertilization rate, impaired on-time development and reduced the implantation rate of the embryos in the IVF-ET process, but it did not affect the development or function of blastocysts. The fmSHS mice produced more Y chromosome-bearing spermatozoa and propagated more male offspring. fmSHS not only reduced the fertilization ability of spermatozoa but also influenced their function beyond fertilization, in addition to changing the offspring sex ratio. These results may help to shed new light on the infertility treatment of males with scrotal heat risk and the health concerns of offspring propagated from these fathers.