Chronic restraint stress induces sperm acrosome reaction and changes in testicular tyrosine phosphorylated proteins in rats

Protective role of hesperidin in finasteride-induced testicular toxicity in adult male Wistar rats: Insights into oxidative stress, apoptosis, and ultrastructure of seminiferous tubules

A negative impact of finasteride on fertility has been reported, in which over production of reactive oxygen species and apoptosis were implicated. Hesperidin, a plant-derived bioflavonoid with antioxidant and anti-apoptotic effects, may mitigate these adverse effects. In order to investigate the possible protective role of hesperidin against finasteride-induced seminiferous tubules toxicity in adult male Wistar rats, 60 rats were randomized into five groups (I-V) receiving distilled water, 0.5% sodium carboxymethylcellulose solution, hesperidin, finasteride, and combined hesperidin and finasteride respectively. Testicular weight, sperm count and motility were determined. Testicular tissue homogenates were prepared to measure the level of malondialdehyde (MDA), total antioxidant capacity (TAC), reduced glutathione (GSH) and the gene expression of caspase-3 and B-cell lymphoma 2 (Bcl2). Testes were processed for light and electron microscopic evaluation. Johnsen score was calculated. Administration of finasteride resulted in significantly decreased testicular weights, sperm count and motility, Johnsen score, tissue levels of TAC and GSH together with significant increase in tissue MDA. Gene expression revealed significantly increased caspase-3 and decreased Bcl2. Furthermore, finasteride disrupted the seminiferous tubules, causing degenerative changes affecting Sertoli cells and spermatogenic cells. Co-administration of hesperidin with finasteride resulted in improvement in testicular weights, TAC, GSH, Bcl2, Johnsen score, sperm count and motility as well as preservation of the structure of the seminiferous tubules. To conclude, hesperidin was found to have a protective potential on finasteride-induced oxidative stress, apoptosis and testicular structural damage.

Prevention of seminal vesicle damage by Mucuna pruriens var. pruriens seed extract in chronic unpredictable mild stress mice

CONTEXT

Thai Mucuna pruriens (L.) DC. var. pruriens (Fabaceae) or T-MP seed extract has been shown to improve sexual performance and sperm quality.

OBJECTIVE

This study investigates the preventive effects of T-MP against seminal vesicle damage, apoptotic and Nrf2 protein expression in mice under chronic unpredictable mild stress (CUMS).

MATERIALS AND METHODS

Forty-eight male ICR mice were divided into four groups: control, CUMS, T-MP300 + CUMS and T-MP600 + CUMS. Mice in control and CUMS groups received distilled water, while those in treated groups were pretreated with T-MP extract (300 or 600 mg/kg BW) for 14 consecutive days. The CMUS and co-treated groups were exposed to one random stressor (of 12 total) each day for 43 days. Components and histopathology of the seminal vesicle were examined, along with localization of androgen receptor (AR) and caspase 3. Expression of seminal AR, tyrosine phosphorylated (TyrPho), heat shock protein 70 (Hsp70), caspases (3 and 9) and nuclear factor erythroid 2-related factor 2 (Nrf2) proteins was investigated.

RESULTS

T-MP extract at a dose of 600 mg/kg BW improved seminal epithelial damage and secretion of fluid containing essential substances and proteins in CUMS mice. It also increased the expression of AR and TyrPho proteins. Additionally, T-MP increased expression of Nrf2 and inhibited seminal vesicular apoptosis through the suppression of Hsp70 and caspase expression.

CONCLUSION

T-MP seeds have an antiapoptotic property in chronic stress seminal vesicle. It is possible to apply this extract for the enhancement of seminal plasma quality.

Seed extract of Thai Mucuna pruriens reduced male reproductive damage in rats induced by chronic stress

CONTEXT

Thai Mucuna pruriens (L.) DC. var. pruriens (Fabaceae) (TMP) is known to enrich reproduction but preventive effects on stress related adverse reproductive parameters are not documented.

OBJECTIVE

This study investigates the protective property of TMP seed extract on reproductive damage under chronic stress (CS).

MATERIALS AND METHODS

Male Sprague-Dawley rats were divided into four groups. The control and CS groups received distilled water, whereas the pre-treated rats received the aqueous TMP seed extract at doses of 150 and 300 mg/kg BW for 20 days before co-treatments with CS induction (immobilization and forced swimming) for 81 days. Serum was used to determine the cortisol and testosterone levels. Histology of testis and epididymis was observed with localization of androgen receptor (AR). Sperm parameters and the expression of steroidogenic acute regulatory (StAR), cytochrome P450 family 11 subfamily a member 1 (CYP11A1), AR, HSP70, caspases (3 and 9) and tyrosine phosphorylation (TyrPho) proteins were investigated.

RESULTS

TMP extract improved cortisol level (0.84 ± 0.02 µg/dL) and protected against the damage of reproductive tissues and sperm parameters (count [49.78 ± 3.74 million sperm/mL], viability [90.01 ± 1.17%] and precocious acrosome reaction [1.38 ± 0.48%]). Expression of testicular StAR, CYP11A1, AR and HSP70 proteins was improved. Caspase expression was decreased in treated rats. TMP increased AR expression in CS sperm. Moreover, TyrPho protein expression was corrected after TMP administration.

CONCLUSIONS

TMP seed protected against adverse reproductive parameters in CS via improvements of functionally testicular markers and reductions of apoptotic proteins. It is possible to develop the TMP beans as an alternative medicine in treating of male subfertility caused by CS.

Sex differences in autonomic responses to stress: implications for cardiometabolic physiology

Chronic stress is a significant risk factor for negative health outcomes. Furthermore, imbalance of autonomic nervous system control leads to dysregulation of physiological responses to stress and contributes to the pathogenesis of cardiometabolic and psychiatric disorders. However, research on autonomic stress responses has historically focused on males, despite evidence that females are disproportionality affected by stress-related disorders. Accordingly, this mini-review focuses on the influence of biological sex on autonomic responses to stress in humans and rodent models. The reviewed literature points to sex differences in the consequences of chronic stress, including cardiovascular and metabolic disease. We also explore basic rodent studies of sex-specific autonomic responses to stress with a focus on sex hormones and hypothalamic-pituitary-adrenal axis regulation of cardiovascular and metabolic physiology. Ultimately, emerging evidence of sex differences in autonomic-endocrine integration highlights the importance of sex-specific studies to understand and treat cardiometabolic dysfunction.

Effects of Achillea tenuifolia Lam. hydro-alcoholic extract on anxiety-like behavior and reproductive parameters in rat model of chronic restraint stress

INTRODUCTION

Achillea tenuifolia Lam (AT) has several biological activities and medicinal properties. In this study, we elucidated the impact of the AT on anxiety-related behaviors, reproductive parameters, antioxidant capacity in male rats subjected to chronic restraint stress (CRS).

METHODS

35 Wistar rats were divided into five groups: control, CRS-control (received normal saline) and three CRS-treated groups received AT extract (100, 150, and 200 mg/kg body weight) for 21 consequences days. To induce CRS rats, the rats were immobilized for 21 days and received the extract orally. On the last day of treatment, anxiety-related behaviors were assessed through the sucrose preference test (SPT) as well as elevated plus maze (EPM) tests. Corticosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH), testosterone levels were evaluated to determine reproductive capacity. Sperm parameters including the total count, motility, and viability were also analyzed. Weight of body, testis and seminal vesicles was measured as well.

RESULTS

The findings revealed that 100, 150, and 200 mg/kg of AT extract had anxiolytic effects in CRS rats, as confirmed by the EPM test and SPT. In addition, AT extract could improve fertile capacity and sperm quality to varying degrees. The level of corticosterone had decreased, whereas the level of LH, FSH and testosterone had increased in CRS-treated rats. Moreover, the reduced level of MDA coincided with an increased rate of antioxidant capacity. Our findings suggest that AT extract could alleviate stress-induced dysfunctions.

CONCLUSION

Overall, these observations would infer that AT extract could improve fertility capacity and behavioral impairment in the stress conditions.

GRAPHICAL ABSTRACT

Assumption pathway describing the probability underlying mechanism of CRS-induced anxiety and reproductive toxicity and protective effect of AT.

Decreased expression of AKAP4 and TyrPho proteins in testis, epididymis, and spermatozoa with low sexual performance of mice induced by modified CUMS

The molecular mechanism of chronic stress especially reduced motility, a major cause of male infertility, has not been proved. It is known that A-kinase anchor protein 4 (AKAP4) and tyrosine-phosphorylated (TyrPho) proteins are involved in progressive motility. This study aimed to investigate the effect of chronic unpredictable mild stress (CUMS) on sexual behaviours, sperm quality, and expressions of AKAP4 and TyrPho proteins in testis, epididymis, and spermatozoa. Sixteen male mice were divided into control and CUMS groups (n = 8/group). Animals were induced by a stressor from twelve stressors for 36 days. Sexual behaviours, corticosterone and testosterone, sperm parameters, and histopathology were observed. The expressions of AKAP4 and TyrPho proteins in testis, epididymis, and spermatozoa were examined. Results showed that CUMS significantly increased corticosterone while serum testosterone level was decreased. Sexual behaviours and sperm parameter quality were significantly decreased. CUMS mice showed vacuolisation and pyknotic cells in seminiferous epithelium and less sperm mass was observed within epididymal lumen. CUMS decreased expressions of AKAP4 and TyrPho proteins in testis, epididymis, and spermatozoa. In conclusion, the decreased expression of AKAP4 and TyrPho proteins may be a mechanism associated with low semen qualities particularly decrease of sperm motility in CUMS.

Chronic stress affects tyrosine phosphorylated protein expression and secretion of male rat epididymis

Chronic stress (CS) is shown to decrease the semen quality with changed expression of tyrosine phosphorylated (TyrPho) proteins in testicular and seminal tissues. However, the alterations of such proteins and fluid contents in the epididymis, producing sperm maturation factors, have never been reported. Sixteen adult rats were randomly divided into 2 groups (n = 8). The control animals were not subjected to stressors whereas CS rats were immobilised within restraint cage (4 hr/day) before cold forced-water swimming (15 min/day) for 60 days. Corticosterone, testosterone, blood glucose level (BGL), malondialdehyde (MDA) and biochemical components in epididymal fluid were assayed. Expressions of heat shock protein 70 (HSP-70), androgen receptor (AR) and TyrPho protein were investigated in epididymal tissue and fluid. Significantly, CS increased the corticosterone and BGL but decreased testosterone and epididymal substance levels. MDA level in tail epididymal fluid and HSP-70 expression in both regions of epididymal tissues and fluids, except in head epididymal fluid of CS were increased. Epididymal tissues showed the decrease of AR expression. Presence and changes of many TyrPho proteins were observed in CS. In conclusion, CS could affect functional proteins particularly TyrPho in epididymis, resulted in low semen quality.

Changes in nitric oxide, carbon monoxide, hydrogen sulfide and male reproductive hormones in response to chronic restraint stress in rats

Gasotrasmitters are endogenously synthesized gaseous molecules that are engaged in cellular physiological and pathological processes. Stress influences various physiological aspects of an organism and amends a normal system's functions, including those of the reproductive system. This study aims to investigate the effect of long-term exposure to restraint stress on the male reproductive system as well as the possible impact of stress on the levels of nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H₂S), and the expression of their producing-enzymes. In this study, rats were subjected to the restraint condition for 2 h per day and 7 days per week for 8 consecutive weeks. The results revealed decreases in the serum levels of kisspeptin-1(Kiss-1), gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone and dehydroepiandrosterone sulfate (DHEA-s); however, corticosterone, gonadotropin-inhibitory hormone (GnIH), estradiol (E2) and prolactin levels increased following restraint stress. The mRNA expression levels of NO synthases (NOSs); neuronal NOS (nNOS), inducible NOS (iNOS) and H₂S synthases; cystathionine-γ-lyase- (CSE), 3-mercaptopyruvate-sulfurtransferase- (3MST) and CO-producing enzyme; heme oxygenase-2 (HO-2) were upregulated in the hypothalamus of restraint rats. Testicular mRNA expression levels of endothelial NOS (eNOS), nNOS, HO-1 and HO-2 were upregulated whereas cystathionine β-synthase (CBS), CSE and 3MST expression levels were downregulated following restraint stress. Concentrations of NO increased in the testes but decreased in the semen of restraint rats. On the contrary, CO levels were reduced in the testes while they were elevated in the semen, whereas H₂S concentrations decreased in both testes and semen of restraint rats. Concentrations of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), as well as total antioxidant capacity (TAC) rose in the testes, while they declined in the semen of the restraint group. Restraint stress decreases the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) in the testes while increasing them in the semen. Collectively, restraint stress negatively impacts male reproductive functions and modulates gasotransmitters producing-enzymes expression in the hypothalamus and testes.

Effect of chronic stress on expression and secretion of seminal vesicle proteins in adult rats

Chronic stress (CS) is known to affect men's health especially fertility by reducing semen quality. Although the effects of CS on testicular function and sperm parameters are documented, changes of substances and secreting proteins in the seminal vesicle (SV) have never been reported. This study aimed to demonstrate the alterations of contents and expressions of proteins in seminal vesicle fluid (SVF) under CS. Fourteen adult rats were divided into control and CS groups (n = 7/each). Control rats were not exposed to stressor, while the CS animals were immobilised by restraint cage (4 hr/day) and followed by forced swimming (15 min/day) for consecutive 60 days. Biochemical substances and malondialdehyde (MDA) level in SVF were examined. Expressions of heat-shock protein 70 (Hsp70), caspases (Casp) 3 and 9, and tyrosine-phosphorylated (TyrPho) proteins were investigated in seminal vesicle tissue (SVT) and SVF. It was found that CS caused reductions of seminal epithelial height and secreted substance levels. Significantly, MDA levels in SVF and expressions of Hsp70, Casp and TyrPho proteins were increased in of CS animals. It was concluded that CS affected seminal secretion. Low quality of CS seminal plasma may associate with increase of MDA and expressions of secreted proteins.

Comparison of male reproductive parameters in mice with type 1 and type 2 diabetes

OBJECTIVE

The differences between type 1 and type 2 diabetes mellitus (T1DM and T2DM) in terms of their adverse effects on male reproductive parameters have never been elucidated. This study aimed to distinguish between the effects of the DM types in mice treated with multiple low doses of streptozotocin (STZ) to mimic human T1DM and coadministered a high-fat diet (HFD) to mimic human T2DM.

METHODS

The T1DM mice were intraperitoneally injected with STZ (40 mg/kg body weight) for 5 days. The T2DM mice received an HFD for 14 days prior to STZ injection (85 mg/kg body weight), followed by continuous feeding of an HFD. Male reproductive parameters were evaluated.

RESULTS

The reproductive organs of the DM mice weighed significantly less than those of controls, and the seminal vesicles plus prostates of the T1DM mice weighed less than those of the T2DM mice. Increased sperm abnormalities and incomplete DNA packaging were observed in the DM groups. Sperm concentration and the proportion of normal sperm were significantly lower in the T1DM group. The seminiferous histopathology of DM mice was classified into seven types. The penises of the DM mice were smaller than those of the controls; however, tunica albuginea thickness and the amount of penile collagen fibers were increased in these mice. Round germ cells were abundant in the epididymal lumens of the mice with DM.

CONCLUSION

T1DM adversely affected reproductive parameters to a greater extent than T2DM.

Identification of Sec23ip, Part of 14-3-3γ Protein Network, as a Regulator of Acute Steroidogenesis in MA-10 Leydig Cells

Testosterone production occurs in the Leydig cells of the testes and is essential for virilization, development, reproduction, and quality of life. Although the steroidogenic proteins involved in cholesterol conversion to testosterone (T) are well characterized, the causes of reduced T during fetal, neonatal, and adult life remain uncertain. It is well established that normal cellular function is achieved through fine-tuning of multiple rather than single protein networks. Our objective was to use mass spectrometry (MS)-based proteomics to identify which cellular pathways, other than the steroidogenic machinery, influence testosterone production in MA-10 mouse tumor Leydig cells. The 14-3-3 family of scaffolds mediate protein-protein interactions facilitating the crosstalk between protein networks. We previously showed that in MA-10 cells, 14-3-3γ is a critical regulator of steroidogenesis. Therefore, identifying proteins that interact with 14-3-3γ during steroidogenesis could provide clues into the other networks involved. Using liquid chromatography (LC)-MS, we identified 688 proteins that interact with 14-3-3γ and thus potentially impact MA-10 cell steroidogenesis. The identified proteins belong to multiple protein networks, including endoplasmic reticulum-Golgi cargo sorting and vesicle biogenesis, micro ribonucleic acid-induced gene silencing, inflammation, and vesicle trafficking, to name a few. We found that silencing one of the candidates, Sec23ip, a protein known to be involved in vesicle trafficking, resulted in decreased steroidogenesis. We further showed that in Sec23ip-silenced MA-10 cells, cholesterol mobilization from the cytoplasmic membrane to mitochondria is impaired. Taken together these data suggest that Sec23ip is involved in cholesterol trafficking to supply cholesterol for acute steroidogenesis through its interactions with 14-3-3γ.

Ghrelin alleviates endoplasmic reticulum stress and inflammation-mediated reproductive dysfunction induced by stress

PURPOSE

Psychological stress exists widely in modern society and results in the disruption of testicular tight junctions, germ cell apoptosis, and the disorder of fertility hormones and even causes infertility. Ghrelin (GHRL), a 28-amino acid peptide secreted mainly by the stomach and pancreas, has been reported to alleviate male reproductive injury through inhibiting apoptosis. However, whether GHRL has a beneficial effect on psychological stress-induced testicular injury and the possible mechanisms remain poorly understood.

METHODS

Male mice were immobilized in Decapicone bags for 3 h daily for 14 days treated with or without GHRL (i.p. 100 mg/kg body weight). Body weight and testicular weight were measured. Histological alterations and apoptosis were examined by H.E. staining and TUNEL staining, respectively. The expression of endoplasmic reticulum (ER) stress markers, inflammatory cytokines, Toll-like receptor 4 (TLR4), and nuclear factor-κB (NF-κB) in the testes was investigated.

RESULTS

Exposure to stress caused testicular histological alterations, an elevation of the Johnsen score, and germ cell apoptosis, while GHRL partially alleviated the adverse effects. The expression of ER stress marker proteins, including GRP78, CHOP, ATF6, p-JNK, and XBP-1, was upregulated in the stress group; however, GHRL treatment significantly suppressed the activation of ER stress in the testes. GHRL also inhibited the expression of TNF-α, IL-1β, IL-6, IL-10, TLR4, and NF-κB.

CONCLUSIONS

GHRL alleviated testicular injury induced by ER stress and inflammation which is associated with the TLR4/NF-κB signaling pathway, and these findings may provide a novel strategy for preventing and treating reproductive dysfunction.

Phyllanthus emblica leaf extract ameliorates testicular damage in rats with chronic stress

Stress affects the male reproductive system and can cause sub-fertility or infertility. Although Phyllanthus emblica L. (PE) extract has been shown to have high antioxidant capacity and protective properties in damaged tissue, the preventive effects of PE extract on testicular function from stress-related impairment have never been demonstrated. This study aimed to investigate the effects of PE aqueous leaf extract on testicular impairment and protein marker changes in rats suffering from chronic stress. Adult male rats were divided into four groups: a control group, a chronic stress (CS) group, and two groups with CS that received different doses of PE extract (50 or 100 mg/kg body weight (BW)). In the treatment groups, the animals were given PE extract daily before stress induction for 42 consecutive days. Stress was induced through immobilization (4 h/d) followed by forced cold swimming (15 min/d). Sperm quality and the histology of the testes and caudal epididymis were examined, as were levels of serum corticosterone, testosterone, and malondialdehyde (MDA). The expressions of testicular steroidogenic acute regulatory (StAR) and tyrosine-phosphorylated proteins were investigated using immuno-Western blot analysis, as these proteins are assumed to play important roles in spermatogenesis and androgen synthesis. The results showed that PE (50 mg/kg BW) significantly increased sperm concentration and testosterone levels, while decreasing corticosterone levels, MDA levels, sperm head abnormalities, and acrosome-reacted sperm in CS rats. In addition, PE at both doses was found to diminish testicular histopathology in the CS rats. We also found that 50 mg/kg BW of PE significantly improved StAR protein expression and altered the intensities of some tyrosine-phosphorylated proteins in testis. We conclude that PE leaf extract at 50 mg/kg BW can prevent testicular damage in rats with CS.