Protective Effects of Resveratrol against Chronic Immobilization Stress on Testis

Evaluation of the Anxiolytic Effect of Ramelteon in Various Rat Models of Anxiety

Background Melatonin was found to have anxiolytic properties in several animal and human studies. The melatonin receptor agonist ramelteon might also have a similar anxiolytic action. Objectives The objective of the study was to evaluate the effect of ramelteon in various rat models of anxiety and to explore the possible mechanism of action. Methods The anxiolytic effect was compared between the control group, diazepam group (1 mg/kg and 0.5 mg/kg), and ramelteon group (0.25 mg/kg, 0.5 mg/kg, and 1 mg/kg) by an elevated plus maze, light-dark box, hole board apparatus, and open field test in Sprague Dawley rats. Antagonists flumazenil, picrotoxin, and Luzindole were used to explore the possible mechanism of action of ramelteon if it showed an anxiolytic property. Results Ramelteon as a standalone drug did not show an anxiolytic effect. However, a combination of ramelteon (1 mg/kg) and diazepam (0.5 mg/kg) showed an anxiolytic effect. Conclusion Further studies can evaluate the use of a fixed-dose combination of ramelteon and already-approved anxiolytic drugs to reduce the dose of the latter.

Resveratrol ameliorates bisphenol A-induced testicular toxicity in adult male rats: a stereological and functional study

BACKGROUND

Bisphenol A (BPA) is one of the most widely used synthetic chemicals worldwide. BPA as an endocrine disruptor affects the reproductive systems through estrogenic and antiandrogenic proprieties. Resveratrol (RES) as a natural polyphenol and potent antioxidant exhibits protective effects against reproductive toxicity by inhibiting of oxidative stress. 48 male rats were divided into eight groups (n=6), including CONTROL, OLIVE OIL (0.5 ml/ day), Carboxy methylcellulose (CMC) (1 ml of 10 g/l), RES (100mg/kg/day), low dose of BPA (25 mg/kg/day), high dose of BPA (50 mg/kg/day), low dose of BPA + RES, and high dose of BPA + RES. All treatments were done orally per day for 56 days. At the end of the 8th week, blood samples were collected for hormone assays. Then, the sperm parameters were analyzed, and the left testis was removed for stereological study.

RESULTS

We showed a significant decrease in sperm parameters in the low and high doses of BPA groups compared to control groups (P<0.05). The volume of testicular components as well as the diameter and length of seminiferous tubules significantly reduced (11-64 %), and the total number of the testicular cell types decreased (34-67 %) on average in the low and high doses of BPA groups. Moreover, serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone hormones concentration showed a significant reduction in both doses of BPA groups (P<0.01). Nonetheless, treatment with RES could ameliorate all the above-mentioned changes in the low and high doses of BPA groups (P<0.05).

CONCLUSIONS

RES could prevent BPA-induced testicular structural changes and sperm quality via improving gonadotropin hormones and testosterone levels.

Mechanistic insights into the protective role of eugenol against stress-induced reproductive dysfunction in female rat model

The challenging and highly demanding life rhythm nowadays subjects people to unavoidable chronic stress. Chronic stress is associated with a wide array of serious health complications including neuroendocrine dysregulations. Women are more prone to chronic stress-related hormonal disturbances and their physical and psychological consequences, especially reproductive impairment. Eugenol is a natural phenolic anti-oxidant that has several beneficial biological activities. The current study intended to scrutinize the potential protective effect of eugenol in female Wistar rats exposed to chronic unpredictable mild stress (CUMS). Rats were randomly allocated into 4 groups; group 1 received olive oil, group 2 received eugenol in olive oil, groups 3 and 4 were subjected to CUMS protocol for 8 weeks, with pre- and concomitant treatment with eugenol (50 mg/kg/day; p.o.) in group 4. The results showed that CUMS exposure led to weight loss and depressive-like behaviours. CUMS induced hypothalamic-pituitary-adrenal axis activation with subsequent elevation of serum corticosterone level which, in turn, caused decline in ovarian release of estradiol and antimullerian hormones together with an increased production of follicle-stimulating and luteinizing hormones by the anterior pituitary, leading to reproductive disturbances. In ovaries, CUMS imposed oxidative stress, insulin resistance and molecular damage. Intriguingly, all these adverse effects were significantly mitigated by the administration of eugenol that improved animals' behaviours, corrected corticosterone upsurge, tempered hormonal disturbances, and amended ovarian damage. All biochemical results were further confirmed by hippocampal and ovarian histopathological examinations. In conclusion, the current study highlights the prophylactic role of eugenol against reproductive disturbances induced by chronic stress in female rats.

The counteracting effects of (-)-Epigallocatechin-3-Gallate on the immobilization stress-induced adverse reactions in rat pancreas

Many studies suggest that Epigallocatechin-3-Gallate (EGCG) has many protective effects. But little is known about its protective effects against chronic restraint stress-induced damage in rats. The aim was to demonstrate the potential protective effects of EGCG against harmful pancreatic damage to the immobilization stress in the rat model. Forty rats, 2 months old, were divided into four groups (n = 10): control group; EGCG group, rats received EGCG by gavage (100 mg/kg /day) for 30 days; stressed group, rats exposed to immobilization stress; and stressed with EGCG group, rats exposed to immobilization stress and received EGCG for 30 days. Glycemic status parameters, corticosterone, and inflammatory markers were investigated on the first day, 15th day, and the 30th day of the experiment. Pancreatic oxidative stress markers and cytokines were evaluated. Histological, immunohistological, and statistical studies were performed. On the 15th day, fasting blood glucose (FBG), fasting plasma insulin (FPI), homeostatic model assessment for insulin resistance (HOMA-IR), and fasting plasma corticosterone were significantly higher in the stressed group when compared with first and 30th day in the same group as well as when compared with control and stressed with EGCG groups. The stressed group revealed significantly higher pancreatic IL-1β, IL-6, TNF-α, MDA, and NO, serum amylase and serum lipase, and significantly lower GSH, SOD, and CAT when compared to control and stressed with EGCG groups. EGCG treatment attenuated the pancreatic stress-induced cellular degeneration, leucocytic infiltration, and cytoplasmic vacuolations; significantly decreased area percentage of collagen fibers; and significantly increased mean area percentage of insulin immunopositive cell as compared with stressed group. EGCG is a protective agent against immobilization stress because of its anti-diabetic, anti-inflammatory, and and anti-oxidative stress properties, as confirmed by biochemical and histological alterations.

Changes in Expressions of Spermatogenic Marker Genes and Spermatogenic Cell Population Caused by Stress

Many young adults are in a state of stress due to social and psychological pressures, which may result in male reproductive dysfunction. To provide new insight into this phenomenon, we investigated the effect of stress on the regulation of key genes and biological events in specific stages of spermatogenesis. After establishing rat stress models of different time durations, we observed pathological changes in testis through haematoxylin and eosin staining, and analysed gene expression in testis by RNA-seq, bioinformatic analysis, and reverse transcription qPCR (RT-qPCR). Immunohistochemistry (IHC) with the TissueFAXS quantitative imaging system was used to verify changes of different population of spermatogenic cells marked by differentially expressed marker genes. Our results showed that prolonged stress can lead to pathological changes in the testes, such as thinning of the spermatogenic epithelium, a decreased number of spermatogenic epithelial cells, the disordered arrangement of spermatogenic cells, and a decreased number of mature sperms. RNA-seq revealed that key marker spermatogenesis-related genes such as Stra8, Sycp3, Piwil1, and Tnp1 had significantly decreased expression levels in chronic stress groups, and this was confirmed by RT-qPCR and IHC. Collectively, these findings suggest that chronic stress causes damaging pathological changes in testis and dysregulates the marker genes of specific stages of spermatogenesis and change the population of spermatogenic cells, which may be a critical responsible for male reproductive dysfunction.

MOTILIPERM Ameliorates Immobilization Stress-Induced Testicular Dysfunction via Inhibition of Oxidative Stress and Modulation of the Nrf2/HO-1 Pathway in SD Rats

It is well established that physiological stress has an adverse effect on the male reproductive system. Experimental studies have demonstrated the promising effects of MOTILIPERM in male infertility. MOTILIPERM extract is composed of three crude medicinal herbs: Morinda officinalis How (Rubiaceae) roots, Allium cepa L. (Liliaceae) outer scales, and Cuscuta chinensis Lamark (convolvulaceae) seeds. The present study aimed to investigate the possible mechanisms responsible for the effects of MOTILIPERM on testicular dysfunction induced by immobilization stress. Fifty male Sprague Dawley rats were divided into five groups (10 rats each): a normal control group (CTR), a control group administered MOTILIPERM 200 mg/kg (M 200), an immobilization-induced stress control group (S), an immobilization-induced stress group administered MOTILIPERM 100 mg/kg (S + M 100), and MOTILIPERM 200 mg/kg (S + M 200). Stressed rats (n = 30) were subjected to stress by immobilization for 6 h by placing them in a Perspex restraint cage, while controls (n = 20) were maintained without disturbance. Rats were administrated 100 or 200 mg/kg MOTILIPERM once daily for 30 days 1 h prior to immobilization. At the end of the treatment period, we measured body and reproductive organ weight; sperm parameters; histopathological damage; reproductive hormone levels; steroidogenic acute regulatory protein (StAR); biomarkers of oxidative stress; and apoptosis markers. MOTILIPERM treatment improved testicular dysfunction by up-regulating (p < 0.05) sperm count, sperm motility, serum testosterone level, StAR protein level, Johnsen score, and spermatogenic cell density in stressed rats. MOTILIPERM decreased oxidative stress by increasing (p < 0.05) testicular superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione peroxidase-4 (GPx 4), catalase, nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase 1 (HO-1) levels and decreasing (p < 0.05) malondialdehyde (MDA) and reactive oxygen species/reactive nitrogen species (ROS/RNS) levels. Furthermore, MOTILIPERM down-regulated (p < 0.05) cleaved caspase 3 and BCL2 associated X protein (Bax) levels; increased pro caspase-3 and B-cell lymphoma 2 (Bcl-2) levels; and upregulated testicular germ cell proliferation in stressed rats. The number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells and serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels also significantly (p < 0.05) decreased after pretreatment with MOTILIPERM in stressed rats. Collectively, our results suggest that, in immobilization-mediated stress-induced testicular dysfunction, MOTILIPERM sustains normal spermatogenesis via antioxidant and anti-apoptotic activities by activating the NRF/HO-1 signaling pathway.

Resveratrol Protects against Restraint Stress Effects on Stomach and Spleen in Adult Male Mice

The objectives were to investigate whether restraint stress (which is known as a mixture of psychologic and physical stress) exerts negative effects on the stomach and spleen, and whether the phenolic compound resveratrol (RES) exerts any protective roles. Fifty adult male mice were divided into five groups, with 10 mice per group as follows: control (C), restraint stress (RS), RS with vehicle (RS + V), RS with 2 mg/kg of resveratrol (RS + 2 mg RES), and RS with 20 mg/kg of resveratrol (RS + 20 mg RES). Mice were restrained in conical centrifuge tubes for 4 h daily to establish the RS model. RS + 2 mg RES, RS + 20 mg RES, and RS + V groups were given an oral dose of resveratrol or vehicle for 15 consecutive days, while the control group was not exposed to restraint stress. Herein, we showed that restraint stress decreased body weight and food and water consumption in stressed groups RS and RS + V compared to controls, while the groups treated with resveratrol showed improvements. Moreover, restraint stress caused acute damage to the morphology of gastric cells and reduced the quantitative distribution of parietal cells along with their decreased size and diameter, pointing to gastritis or ulcer. Furthermore, the antibody against the apoptosis-inducing factor (AIF) was highly attached in the RS groups. Splenic size, weight, and length were also greatly augmented in the stressed groups compared to the controls, while these phenomena were not observed in the RS + 2 mg RES group. Our findings proved significant ameliorating effects of resveratrol against restraint stress in adult male mice.

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.

Protective effects of Korean Red Ginseng against sub-acute immobilization stress-induced testicular damage in experimental rats

Background

Excessive stress causes varied physiological and psychological disorders including male reproductive problems. Here, we attempted to investigate the protective effects of Korean Red Ginseng (Panax ginseng Meyer; KRG) against sub-acute immobilization stress-induced testicular damage in experimental rats.

Methods

Male rats (age, 4 wk; weight, 60–70 g) were divided into four groups (n = 8 in each group): normal control group, immobilization control group, immobilization group treated with 100 mg/kg of KRG daily, and immobilization group treated with 200 mg/kg of KRG daily. Normal control and immobilization control groups received vehicle only. KRG (100 mg/kg and 200 mg/kg) was mixed in the standard diet powder and fed daily for 6 mo. Parameters such as organ weight, blood chemistry, sperm kinematic values, and expression levels of testicular-related molecules were measured using commercially available kits, Western blotting, and reverse transcription polymerase chain reaction.

Results

Data revealed that KRG restored the altered testis and epididymis weight in immobilization stress-induced rats significantly (p < 0.05). Further, KRG ameliorated the altered blood chemistry and sperm kinematic values when compared with the immobilization control group and attenuated the altered expression levels of spermatogenesis-related proteins (nectin-2, cAMP responsive element binding protein 1, and inhibin-⍺), sex hormone receptors (androgen receptor, luteinizing hormone receptor, and follicle-stimulating hormone receptor), and antioxidant-related enzymes (glutathione S-transferase m5, peroxiredoxin-4, and glutathione peroxidase 4) significantly in the testes of immobilization stress-induced rats.

Conclusion

KRG protected immobilization stress-induced testicular damage and fertility factors in rats, thereby indicating its potential in the treatment of stress-related male sterility.

Neuroprotective effects of melatonin administration against chronic immobilization stress in rats

Chronic stress can impair brain functions and play a well-known role in the development of stress-related disorders such as anxiety. Melatonin (Mel) is a neurohormone which regulate several physiological processes including mood and behavior. This experimental study was designed to evaluate the effect of Mel on chronic immobilization stress (CIS) for 6 weeks in rats and to elucidate its possible underlying mechanisms. Twenty-eight adult male Wistar albino rats were divided into four equal groups: the control group, the Mel-treated group which was injected daily with Mel (10 mg/kg/day; IP) for 6 weeks, the stressed group which was subjected to CIS protocol daily for 6 weeks, and the Mel-treated stressed group which was injected with Mel and concurrently exposed to CIS protocol for 6 weeks. The Mel-treated stressed group showed reduction of both relative adrenal weight and the serum corticosterone levels, suppression of the anxiety-like behavior, increased levels of serotonin, noradrenaline and oxytocin in the frontal cortex, and improved histopathological structure and decreased chromogranin A (CgA) protein expression in the frontal cortex when compared with the chronically stressed group. We concluded that Mel is anxiolytic and this effect was mediated in part by its ability to increase the central release of oxytocin and monoamines and to downregulate CgA protein expression in the frontal cortex.

Changes of testicular phosphorylated proteins in response to restraint stress in male rats

OBJECTIVE

To investigate male reproductive parameters via changes of potential testicular protein markers in restraint-stress rats.

METHODS

Male Sprague-Dawley rats were divided into two groups (non-immobilized control and restraint-immobilized/stress groups, n=8 each group). The stress animals were immobilized (12 h/d) by a restraint cage for 7 consecutive days. All reproductive parameters, morphology and histology were observed and compared between groups. In addition, the expression of steroidogenic acute regulatory (StAR) and phosphotyrosine proteins (previously localized in Sertoli and late spermatid cells) in testicular lysate was assayed by immuno-Western blotting.

RESULTS

Testosterone level, sperm concentration and sperm head normality of stress rats were significantly decreased while the corticosterone level was increased as compared with the control (P<0.05). Histologically, stress rats showed low sperm mass in epididymal lumen and some atrophy of seminiferous tubules. Although the expression of testicular StAR protein was not significantly different between groups, changed patterns of the 131, 95, and 75 kDa testicular phosphorylated proteins were observed in the stress group compared with the control group. The intensity of a testicular 95-kDa phosphorylated protein was significantly decreased in stress rats.

CONCLUSIONS

This study has demonstrated the alteration of testicular phosphorylated protein patterns, associated with adverse male reproductive parameters in stress rats. It could be an explanation of some infertility in stress males.

Moringa oleifera extract enhances sexual performance in stressed rats

Aphrodisiacs are required to improve male sexual function under stressful conditions. Due to the effects of oxidative stress and dopamine on male sexual function, we hypothesized that Moringa oleifera leaves might improve male sexual dysfunction induced by stress. Therefore, the effects on various factors playing important roles in male sexual behavior, such as antioxidant effects, the suppression of monoamine and phosphodiesterase type 5 (PDE-5) activities, serum testosterone and corticosterone levels, and histomorphological changes in the testes, of a hydroethanolic extract of M. oleifera leaves were investigated. Various doses of extract including 10, 50, and 250 mg/kg body weight (BW) were given orally to male Wistar rats before exposure to 12 h-immobilization stress for 7 d. The results demonstrated that the extract showed both antioxidant and monoamine oxidase type B (MAO-B) suppression activities. At 7 d of treatment, the low dose of extract improved sexual performance in stress-exposed rats by decreasing intromission latency and increasing intromission frequency. It also suppressed PDE-5 activity, decreased serum corticosterone level, but increased serum testosterone, numbers of interstitial cells of Leydig and spermatozoa. The increased numbers of interstitial cells of Leydig and spermatozoa might have been due to the antioxidant effect of the extract. The increased sexual performance during the intromission phase might have been due to the suppression of MAO-B and PDE-5 activities and increased testosterone. Therefore, M. oleifera is a potential aphrodisiac, but further research concerning the precise underlying mechanisms is still needed.