Inhibitory effects of stress-activated nitric oxide on antioxidant enzymes and testicular steroidogenesis

Influence of l-NAME -induced hypertension on spermatogenesis and sperm tsRNA profile in mice

Sperm is the key media between the father's aberrant exposure and the offspring's phenotype. Whether paternal hypertension affects offspring through sperm epigenetics remains to be explored. To investigate the underlying mechanisms, we constructed a hypertensive mice model induced by drinking l-NAME and found that spermatocytes and spermatids in the testis were increased significantly after l-NAME treatment. The sequencing of sperm showed that tsRNA profiles changed with 315 tsRNAs (195 up-regulated and 120 down-regulated) altered. Meanwhile, KEGG pathway analysis showed that the target genes of these altered tsRNAs were involved in influencing some important signaling pathways, such as the cAMP signaling path, the mTOR signaling path, the Hippo signaling path, and the Ras signaling path. Bioinformatics of tsRNA-miRNA-mRNA pathway interactions revealed several ceRNA mechanisms, such as tsRNA-00051, the ceRNA of miR-128-1-5p, co-targeting Agap1. This study provides evidence for enriching and further understanding the pathophysiology and paternal epigenetic mechanisms of testicular reproduction, as well as contributing to a rethinking of the transgenerational reprogramming mechanisms of paternal exposure in hypertension.

Beneficial role of naringin against methotrexate-induced injury to rat testes: biochemical and ultrastructural analyses

Background

Methotrexate (MTX) is a commonly used chemotherapeutic drug that has adverse toxic effects on germ cells. Naringin (NG) is a natural flavanone glycoside, with different phytotherapeutic applications, and its possible protective effects against MTX-induced testicular tissue damage were investigated in this study.

Methods

Low and high doses of NG (40 and 80 mg/kg/day) were given for 10 days by intraperitoneal (i.p.) injection and MTX (20 mg/kg i.p.) was given at the 4th day of the experiment, with or without NG in rats.

Results

The obtained results showed that exposure to MTX increased malondialdehyde (MDA) levels and nitric oxide (NO) production compared with the control. In the meantime, MTX depleted catalse (CAT), superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GPx), and reduced glutathione (GSH) in the testicular tissue. Further, serum testosterone levels were significantly decreased in the MTX group. NG significantly counteracted the aforementioned effects of MTX; however, NG80 was more effective in restoring SOD, GR, MDA and NO. Interestingly, NG80 achieved a better improvement in the ultrastructural pattern of the testicular cells in MTX-exposed rats.

Conclusion

These results indicated, for the first time, that NG could be a potential candidate therapy against MTX-reprotoxic impacts.

Alterations in the testicular parenchyma of Foxn1+/- and Foxn1-/- adult mice

Nude mice carry an autosomal recessive mutation in the Foxn1 gene and therefore are homozygous recessive animals (Foxn1 -/-). The fertility rate of homozygous male (Foxn1-/- ) is low, which seems to be related to the delay in the production of gametes at the beginning of sexual maturity. The present study evaluated the structural and organizational aspects of the testicles of homozygous and heterozygous offspring related to the Foxn1 gene in mice, describing its implications on spermatogenesis. Adult males Balb/c, Foxn1+/- and Foxn1-/- mice were used. Testes and epididymis were harvested for histological, biochemical, and sperm transit analyses. Gonadal weight was significantly lower in Foxn1+/- and Foxn1-/- animals, the same behavior was noticed for the activity of antioxidant enzymes. In addition, tubular parameters such as epithelial proportion, length, and area, as well as germ and Leydig cell's populations were significantly reduced in the aforementioned groups, leading to lower sperm production. In conclusion, our results indicate the importance of the Foxn1 in Leydig cell's function, reflecting in the preservation of spermatogenesis, thus in germ cell's population and sperm cell production.

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.

Regulation of Human Spermatogenesis

Human spermatogenesis (HS) is an intricate network of sequential processes responsible for the production of the male gamete, the spermatozoon. These processes take place in the seminiferous tubules (ST) of the testis, which are small tubular structures considered the functional units of the testes. Each human testicle contains approximately 600-1200 STs [1], and are capable of producing up to 275 million spermatozoa per day [2].

How bad is brazilian ginseng extract for reproductive parameters in mice?

Properties attributed to the Panax ginseng are also attributed to the Brazilian ginseng, such as adaptogenic and aphrodisiac effects. There are studies demonstrating that the Brazilian ginseng (BGE) possibly increases the serum levels of testosterone and nitric oxide in mice and rats. The present study aimed to evaluate the effects of its extract on male fertility and sperm quality. Male Swiss mice (n = 60) were divided into six groups. The control animals were provided 0.5 mL of water, and 0.5 mL of water containing 7 mg/kg per day (d) sildenafil citrate. Other animals were treated with BGE at 100 mg/kg/d, 200 mg/kg/d, and 400 mg/kg/d by gavage for 42 days. Finally, animals from the last group received 200 mg/kg BGE every 3 days (3-3d) by gavage for 42 days. The results showed a reduction in the number of resistant spermatids in the testis and damage to daily sperm production, culminating in a reduction in the number of epididymal spermatozoa. Although the sperm quality decreased in all experimental animals, only males treated with BGE 100 mg/kg/d showed pre and post implantation embryo losses. We concluded that BGE alters sperm viability compromising the embryonic development after implantation.

Arginine supplementation improves growth, antioxidant capacity, immunity and disease resistance of juvenile Chinese mitten crab, Eriocheir sinensis

To investigate the effects of arginine (Arg) on the growth, antioxidant capacity, immunity and disease resistance of juvenile Chinese mitten crab, three diets containing Arg levels at 1.72% (control), 2.73% and 3.72% were formulated and fed to Chinese mitten crab (0.22 ± 0.03 g) for eight weeks. The weight gain, ecdysterone and growth hormone in the serum, relative expression of insulin-like growth factor 2 in the hepatopancreas significantly increased in crabs fed the 2.73% and 3.72% Arg diets. The protein and lipid contents significantly increased in crabs fed the 3.72% Arg diet. The feed conversion ratios in crabs fed the diets with Arg additions were lower than in the control. Arg supplementation also enhanced the antioxidative capacity by increasing the activities of superoxide dismutase, catalase and the relative expression of Kelch-like ECH-associated protein 1 gene in the hepatopancreas, which subsequently decreased malondialdehyde content in the hepatopancreas. Besides, Arg also decreased nitric oxide content in the serum and the activity of nitric oxide synthetase in the hepatopancreas. The relative mRNA levels of crustin, relish, lysozyme and cryptocyanin genes were significantly upregulated by Arg supplementation. The activities of acid phosphatase and alkaline phosphatase in the serum significantly increased in crabs fed the 3.72% Arg diet than those in the control. Similarly, the relative mRNA levels of crustin, cryptocyanin and proPO genes were significantly upregulated in crabs fed the 2.73% Arg diet after lipopolysaccharide challenge, and in crabs fed the 3.72% Arg diet after the Poly (I:C) challenge. The crabs fed the 2.73% and 3.72% Arg diets had higher survival rate after bacterial infection than those fed the control diet. This study indicates that the addition of Arg to the diet at 2.7-3.7% can improve the growth, survival, antioxidant capacity, immunity and disease resistance in juvenile Chinese mitten crab.

Nitrate: An Environmental Endocrine Disruptor? A Review of Evidence and Research Needs

Nitrate is heavily used as an agricultural fertilizer and is today a ubiquitous environmental pollutant. Environmental endocrine effects caused by nitrate have received increasing attention over the last 15 years. Nitrate is hypothesized to interfere with thyroid and steroid hormone homeostasis and developmental and reproductive end points. The current review focuses on aquatic ecotoxicology with emphasis on field and laboratory controlled in vitro and in vivo studies. Furthermore, nitrate is just one of several forms of nitrogen that is present in the environment and many of these are quickly interconvertible. Therefore, the focus is additionally confined to the oxidized nitrogen species (nitrate, nitrite and nitric oxide). We reviewed 26 environmental toxicology studies and our main findings are (1) nitrate has endocrine disrupting properties and hypotheses for mechanisms exist, which warrants for further investigations; (2) there are issues determining actual nitrate-speciation and abundance is not quantified in a number of studies, making links to speciation-specific effects difficult; and (3) more advanced analytical chemistry methodologies are needed both for exposure assessment and in the determination of endocrine biomarkers.

Stress triggers mitochondrial biogenesis to preserve steroidogenesis in Leydig cells

Adaptability to stress is a fundamental prerequisite for survival. Mitochondria are a key component of the stress response in all cells. For steroid-hormones-producing cells, including also Leydig cells of testes, the mitochondria are a key control point for the steroid biosynthesis and regulation. However, the mitochondrial biogenesis in steroidogenic cells has never been explored. Here we show that increased mitochondrial biogenesis is the adaptive response of testosterone-producing Leydig cells from stressed rats. All markers of mitochondrial biogenesis together with transcription factors and related kinases are up-regulated in Leydig cells from rats exposed to repeated psychophysical stress. This is followed with increased mitochondrial mass. The expression of PGC1, master regulator of mitochondrial biogenesis and integrator of environmental signals, is stimulated by cAMP-PRKA, cGMP, and β-adrenergic receptors. Accordingly, stress-triggered mitochondrial biogenesis represents an adaptive mechanism and does not only correlate with but also is an essential for testosterone production, being both events depend on the same regulators. Here we propose that all events induced by acute stress, the most common stress in human society, provoke adaptive response of testosterone-producing Leydig cells and activate PGC1, a protein required to make new mitochondria but also protector against the oxidative damage. Given the importance of mitochondria for steroid hormones production and stress response, as well as the role of steroid hormones in stress response and metabolic syndrome, we anticipate our result to be a starting point for more investigations since stress is a constant factor in life and has become one of the most significant health problems in modern societies.

Quinestrol induces spermatogenic apoptosis in vivo via increasing pro-apoptotic proteins in adult male mice

The effects of quinestrol on spermatogenesis were investigated in adult male mice by daily intragastric administration of quinestrol with various doses of 5, 10, 50 and 100mg/kg body weight for 10 days. The sperm counts declined while the number of abnormal spermatozoa went up in mice treated with quinestrol. The testicular weight and seminiferous tubular area gradually declined with increasing dosages of quinestrol to 50 and 100mg/kg. Rarefied germ cells showed irregular distributions in the seminiferous tubules of mice treated with 50 and 100mg/kg quinestrol. Apoptosis was highly pronounced in spermatogonia, spermatocytes, spermatids and Leydig cells. Antioxidant enzyme activities - superoxide dismutase and glutathione peroxidase - as well as total antioxidant capacity significantly reduced, while malondialdehyde contents increased. The number of germ cells expressing caspase-3, p53, Bax and FasL significantly increased whereas cells expressing Bcl-2 significantly decreased in groups treated with 50 and 100mg/kg quinestrol compared with the control. The concentration of nitrogen monoxidum also increased significantly under these dosages. The results suggest that quinestrol stimulates oxidative stress to induce apoptosis in spermatogenic cells through the mitochondrial and death receptor pathways in adult male mice.

Protective Effects of Resveratrol against Chronic Immobilization Stress on Testis

Objective. The aim of this study was to investigate protective effects of resveratrol, a strong antioxidant, against possible negative effects of chronic immobilization stress on testes of male rats histochemically, immunohistochemically, ultrastructurally, and biochemically. Material and Methods. Male Wistar rats were divided into 4 groups (n = 7). Group I, control group (C), was not exposed to stress. Group II, stress group (S), was exposed to chronic immobilization stress. In Group III, low dose resveratrol + stress group (LRS), rats were given 10 mg/kg/day resveratrol just before the stress application. In Group IV, high dose resveratrol + stress group (HRS), rats were given 20 mg/kg/day resveratrol just before the stress application. For chronic immobilization stress application animals were put in the plastic tubes (6 cm in diameter, 15 cm in length) during 32 days for 6 hours. All animals were sacrificed 18 hours after the last stress application. Results. Histochemical and ultrastructural investigations showed that in stress group there was germ cell deprivation in seminiferous tubules and increase of connective tissue on interstitial area. No significant changes were seen in low and high dose resveratrol groups. After immunohistochemical investigations, TUNEL (+) and Active Caspase-3 (+) cells were increased in seminiferous tubules of stress group compared with those control group, but they were decreased in low and high dose resveratrol groups. According to biochemically results, MDA, GSH, and testosterone levels in stress group showed no significant difference when compared with those of the other groups. Conclusion. The chronic immobilization stress increases oxidative stress and apoptosis and causes histological tissue damages; resveratrol can minimize the histological damage in testes significantly.

Atrazine effects on antioxidant status and xenobiotic metabolizing enzymes after oral administration in peripubertal male rat

Previously, we reported that in vivo applied atrazine from postnatal day 23 to 50 induced strong inhibition of testicular steroidogenesis. Therefore, the aim of the present study was to investigate, in the same experimental model, the oxidative status in androgen-producing testicular interstitial compartment characterized by diminished steroidogenesis. In parallel, we determined activities of antioxidative and cytochrome P450 (CYP) xenobiotic-metabolizing enzymes in liver. To confirm the results on atrazine induced-inhibition of testicular androgenesis, we measured ex vivo production of androgen in Leydig cells. The results revealed decreased activity of antioxidant enzymes, especially glutathione S-transferase (GST), but also glutathione peroxidase (GSH-Px) and catalase (CAT) in testicular interstitial cells, in parallel with strongly diminished ex vivo basal and agonist-stimulated Leydig cell androgenesis. In liver, atrazine increased the activity of GSH-Px, GST, and CYP1A1/2 enzyme, but not lipid peroxidation. These results indicate that atrazine markedly affects both antioxidant status and androgenesis in peripubertal rats.

Exogenous arachidonate restores the dimethoate-induced inhibition of steroidogenesis in rat interstitial cells

The present work studies the potential restorative effect of polyunsaturated fatty acids (PUFA, 5 μM/24 h) on the dimethoate (DMT)-induced inhibition of testosterone biosynthesis in Leydig cells isolated from rat testes. Various fatty acids (FA) from the n-6 (18:2, 20:3, 20:4, 22:4 and 22:5) and n-3 (18.3, 20:5, 22:5, 22:6) series were assayed in Leydig cells, alone (as delipidated BSA complexes) and in combination with DMT (1 ppm). The n-6 FA stimulated lipid peroxidation (LPO) and inhibited the activities of steroidogenic enzymes (3β- and 17β-hydroxysteroid dehydrogenases). The n-3 FA exerted an anti-oxidant effect, decreasing the production of thiobarbituric-acid reactive substances (TBARS) and inhibiting phospholipase A(2) activity. The biosynthesis of testosterone in DMT-treated cultures was completely normalized by ARA (20:4n-6) and partially restored by the addition of 20:3n-6, increasing ARA content inside the mitochondria. The other FA assayed failed to restore androgenesis. COX-2 protein and prostaglandin F2α and E2 production were stimulated by 20:3n-6, ARA, 18:3n-3 and 20:5 n-3. COX-2 protein decreased upon addition of 22:5n-3 and 22:6n-3. StAR protein was increased by ARA and partially increased by 20:3n-6, likely due to its metabolic conversion into ARA. Both FA increased the mitochondrial cholesterol pool available for testosterone biosynthesis. The rate of androgenesis is likely the result of various regulatory factors acting concomitantly on the physiology of Leydig cells.

eNOS activation and NO function: differential control of steroidogenesis by nitric oxide and its adaptation with hypoxia

Nitric oxide (NO) plays a role in a wide range of physiological processes. Aside from its widely studied function in the regulation of vascular function, NO has been shown to impact steroidogenesis in a number of different tissues. The goal of this review is to explore the effects of NO on steroid production and further, to discern its source(s) and mechanism of action. Attention will be given to the regulation of NO synthases in specific endocrine tissues including ovaries, testes, and adrenal glands. The effects of hypoxia on generation of NO and subsequent effects on steroid biosynthesis will also be examined. Finally, a potential model for the interaction of hypoxia on NO synthesis and steroid production is proposed.

Impairment of spermatogenesis in rats by mercuric chloride: involvement of low 17β-estradiol level in induction of acute oxidative stress

Mercuric chloride (HgCl(2)) has been shown to affect the male reproductive organs, and oxidative stress has been linked with hypospermatogenesis and with male infertility. However, the specific mode of impairment of spermatogenesis during HgCl(2) exposure has not yet been clarified fully. Because of the involvement of 17β-estradiol (E2) in the male reproductive tract and its putative role on spermatogenesis, the present study aimed to investigate the possibility that HgCl(2)-induced oxidative stress-mediated modulation of the E2 level exerts adverse effects on testicular steroidogenic and gametogenic activities. HgCl(2) treatment at 50 and 100 ppm for 90 days by continuous oral administration in the drink water resulted in significant dose-dependent fashion decrease in serum and testicular E(2) levels and an increase in testicular testosterone levels in dose-dependent manner, without statistical alteration in serum testosterone level among HgCl(2) exposed groups compared to the control. Cauda epididymal sperm count and motility were decreased significantly (p < 0.01), in a dose-dependent manner, in the HgCl(2)-treated groups, and qualitative examination revealed inhibition of spermatogenesis and the preferential loss of maturing and elongated spermatids. The seminiferous tubules were dilated in treated animals. When compared to the control, increase in lipid peroxidation due to toxic effects of HgCl2 was accompanied by significant reduction (p < 0.01) in antioxidant enzymes activities, superoxide dismutase, catalase, and glutathione peroxidase of testes, implicating the presence of oxidative tissue damage. Furthermore, these tissue injuries caused functional impairment as evidenced with testicular elevated activity of lactate dehydrogenase. Unless oxidative stress can lead to cancer development, testis' tumor markers as beta human chorionic gonadotropin and alpha-fetoprotein levels have shown no significant differences in the HgCl(2)-exposed group compared with respect to the control. Large quantities of metal accumulated in the testis tissue are in agreement with the testis-activity failure verified in this tissue. These findings suggest that a decrease in E2 level after mercury exposure may render testis more susceptible to oxidative damage leading to its functional inactivation, thus providing new dimension to mechanisms underlying heavy metal-induced male infertility.

The impact of the phyto-oestrogen genistein on swine granulosa cell function

Soya and soybean products used in swine feeding contain genistein, a non-steroidal phyto-oestrogen which has been demonstrated to influence endocrine functions. This observation leads us to design this study to evaluate the effect of genistein on swine granulosa cell steroidogenesis and proliferation. In the attempt to unravel the genistein signal transduction mechanisms, we verified the effect of lavendustin, a Tyrosine Kinase (TK) inhibitor, and the potential involvement of NO/cGMP pathway. Finally, as angiogenesis is essential for follicle development, we tested the effect of the phyto-oestrogen on vascular endothelial growth factor production and on granulosa cell redox status, because free-radical species modulate neovascularization. Our data provide evidence that genistein interferes with granulosa cell steroidogenesis while it does not modulate cell growth: this effect could be at least partially produced by inhibiting TK-dependent signalling systems. On the contrary, NO/cGMP pathway or vascular endothelial growth factor production can be excluded as signalling mechanism involved in phyto-oestrogen effects. Remarkably, genistein stimulates hydrogen peroxide production thus potentially inhibiting follicular angiogenesis. Collectively, these results suggest that genistein consumption could potentially negatively impact swine reproductive function.

Nitric oxide inhibits ACTH-induced cortisol production in near-term, long-term hypoxic ovine fetal adrenocortical cells

We previously reported that in the sheep fetus, long-term hypoxia (LTH) resulted in elevated basal plasma adrenocorticotropic hormone (ACTH(1- 39)) whereas the cortisol levels were not different from normoxic controls. We also showed that LTH enhances endothelial nitric oxide synthase (eNOS) expression in the fetal adrenal. This study was designed to determine the effect of NO on cortisol production in adrenocortical cells from LTH fetal sheep. Ewes were maintained at high altitude (3820 m) from ∼40 days' gestation (dG) to near term. Between 138 and 141 dG, fetal adrenal glands were collected from LTH and age-matched normoxic control fetuses. Adrenal cortical cells were pretreated with sodium nitroprusside (SNP), nitro-L-arginine methyl ester (L-NAME), L-arginine, or diethyleneamine NO (DETA-NO) and then challenged with 10 nmol/L ACTH. Cortisol responses were compared after 1 hour. Adrenocorticotropic hormone -induced cortisol secretion was significantly higher in LTH versus control (P < .01). Enhancement of NO with L-arginine resulted in a significant reduction of ACTH-mediated cortisol production in the LTH group. DETA-NO also caused a significant decrease in ACTH-mediated cortisol production (P < .05). Inhibition of NOS with L-NAME significantly increased cortisol production in the LTH group (P < .05 compared to ACTH alone), whereas the effect on the control group was not significant. Nitric oxide synthase activity was significantly higher in the LTH group compared to control, but this difference was eliminated following ACTH treatment. These data indicate that LTH enhances adrenal cortical sensitivity to the inhibitory effects of NO on cortisol production. Nitric oxide may, therefore, play an important role in regulating ACTH-induced cortisol production in the LTH fetal adrenal.

Protective role of propolis against reproductive toxicity of triphenyltin in male rabbits

Triphenyltin (TPT) is known to cause endocrine disruption, reproductive toxicity and a decrease in testosterone production. It is involved in the production of reactive oxygen species. Propolis has been reported to be an important antioxidant. Therefore, the present study aimed to elucidate the possible protective effects of propolis in alleviating the toxicity of triphenyltin chloride (TPTCl) on reproductive performance, testosterone levels, lipid peroxidation and enzyme activities in seminal plasma of male New Zealand white rabbits. Animals were orally administered the doses of propolis, TPTCl and propolis plus TPTCl every day for 12weeks. Results showed that semen quality was deteriorated following treatment with TPTCl. Also, testosterone levels, body weight (BW), relative weights of testes (RWT) and epididymis (RWE) were decreased. Thiobarbituric acid-reactive substances and lactate dehydrogenase were increased, while glutathione S-transferase, transaminases and phosphatases were decreased in seminal plasma of rabbits treated with TPTCl compared to control. Propolis alone significantly increased testosterone levels, BW, RTW, REW, semen characteristics and seminal plasma enzymes, and decreased the levels of free radicals and lactate dehydrogenase. Furthermore, the presence of propolis with TPTCl alleviates its toxic effects. From the present study, it can be concluded propolis can be effective in the protection of TPTCl-induced reproductive toxicity.

Involvement of lipids in dimethoate-induced inhibition of testosterone biosynthesis in rat interstitial cells

The mechanism involved in the inhibition of testosterone (Te) biosynthesis after a sub-chronic exposure to low doses of dimethoate (D) was studied in rat interstitial cells (IC). Expression of COX-2 in IC isolated from D-treated rats increased by 44% over C data, while transcription of StAR decreased by approx. 50% and the expression of this protein was diminished by approximately 40%. PGE(2) and PGF(2alpha) were increased by 61 and 78%, respectively. Te concentration decreased by 49% in IC homogenates. Concomitantly, plasma concentration of LH and FSH both increased. Araquidonate (ARA) and C(22) fatty acyl chains in phospholipids from IC mitochondrial fraction decreased by approx. 30% after D treatment. Protein carbonyls, lipoperoxides and nitrite content increased while alpha-tocopherol and the antioxidant capacity of the soluble cellular fraction decreased significantly. Stimulation with h-CG 10 nM overnight failed to overcome the inhibition caused by D on both Te biosynthesis and 3beta- and 17beta-hydroxysteroid dehydrogenases. Decreased Te biosynthesis may be attributed to (1) inhibition of StAR protein activity due to the stimulation of COX-2 and the overproduction of PGF(2alpha), (2) decreased stimulatory effect of ARA on StAR with a subsequent reduction in the availability of CHO for the androgenic pathway, and/or (3) indirect inhibition of steroidogenic enzymes by a lower transcriptional rate caused by elevated PGF(2alpha). Rofecoxib administration prevents the deleterious effect(s) exerted by D.

Gossypol, a polyphenolic aldehyde from cotton plant, interferes with swine granulosa cell function

Gossypol is a polyphenol isolated from the seed, roots and stem of cotton plant (Gossypium sp.) It has been associated with adverse effects on female reproduction, but recently also shown having promising effects against several malignancies. Its mechanisms of action are however still not fully understood. This study was therefore conducted to investigate the effect of 5 or 25 microg/mL gossypol on swine granulosa cell steroidogenic activity, redox status and Vascular Endothelial Growth Factor (VEGF) production. Study demonstrated that gossypol significantly (P<0.001) inhibited granulosa cell estradiol 17beta and progesterone production, an effect that could be at least partially mediated by an increase (P<0.05) of nitric oxide and superoxide anion production as a consequence of superoxide dismutase inhibition. Moreover, gossypol stimulates (P<0.001) VEGF production. In conclusion, study has demonstrated effects of gossypol on swine granulosa cell function in vitro. Effects on female swine fertility can not be excluded.

Inflammatory networks in the control of spermatogenesis : chronic inflammation in an immunologically privileged tissue?

Spermatogenesis is a complex, organized process involving intimate interactions between the developing germ cells and supporting Sertoli cells. The process is also highly regulated. Studies suggest that regulation in the seminiferous epithelium involves molecules normally associated with either immune or inflammatory processes; in particular, interleukin 1a (IL1a), IL6, tumor necrosis factor (TNFa), activin A and nitric oxide (NO). While there is considerable evidence that these inflammatory mediators have effects on spermatogonial and spermatocyte development as well as critical supportive functions of the Sertoli cells, which are undoubtedly of considerable importance during testicular inflammation, there remains some skepticism regarding the significance of these molecules with respect to normal testicular function. Nonetheless, it is evident that expression of these regulators varies across the cycle of the seminiferous epithelium in a consistent manner, with major changes in production coinciding with key events within the cycle. This review summarizes the evidence supporting the hypothesis that inflammatory cytokines play a role in normal testicular spermatogenesis, as well as in the etiology of inflammation induced sub-fertility. The balance of data leads to the striking conclusion that the cycle of the seminiferous epithelium resembles a chronic inflammatory event. This appears to be a somewhat paradoxical assertion, since the testis is an immunologically privileged tissue based on its well-established ability to support grafts with minimal rejection responses. However, it may be argued that local immunoregulatory mechanisms, which confer protection from immunity on both transplanted tissues and the developing spermatogenic cells, are equally necessary to prevent local inflammation responses associated with the spermatogenic process from activating the adaptive immune response.

In vivo and in vitro effects of PCB126 and PCB153 on rat testicular androgenesis

In this study we compared the effects of PCB126 and PCB153 on adult rat testicular androgenesis and the status of antioxidant enzymes in the interstitial cell compartment 96h after local intratesticular application. Obtained results indicated PCB126-induced inhibition of conversion of progesterone (P) and Δ(4)-androstenedione (A(4)) to testosterone (T), and stimulation of conversion of P to T induced by PCB153, while combined application had no effect. Activities of antioxidant enzymes were unchanged, except of decreased activity of SOD in PCB126-treated group. In parallel experiments, adult purified Leydig cells challenged with PCB congeners were incubated for 2h in the presence of corresponding steroid substrates. Results demonstrated that in the presence of subsaturating substrate concentrations PCB126 induced inhibition of conversion of P and A(4) to T at nM to μM doses, while PCB153 caused stimulation at nM concentrations. Further studies should indicate possible mechanism(s) of modulation of androgenesis by tested PCB congeners.

Effect of aminoguanidine on visual evoked potentials (VEPs), antioxidant status and lipid peroxidation in rats exposed to chronic restraint stress

The purpose of the study was to investigate the effect of aminoguanidine (AG) on visual evoked potentials (VEPs), thiobarbituric acid reactive substances (TBARS), the activities of Cu, Zn superoxide dismutase (Cu,Zn-SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), and nitrite/nitrate levels. Forty healthy male Wistar rats, aged 3 months, were divided into four equal groups: Control (C), the group treated with aminoguanidine (A), the group exposed to restraint stress (S), the group exposed to restraint stress and treated with aminoguanidine (AS). Chronic restraint stress was applied for 21 days (1 h/day) and aminoguanidine (50 mg/kg/day) was injected intraperitoneally to the A and AS groups for the same period. Aminoguanidine treatment significantly decreased retina and brain TBARS levels in rats exposed to restraint stress compared to rats exposed to restraint stress alone. Aminoguanidine treatment produced a significant decrease in brain and retina nitrite and nitrate levels with respect to the control groups. Aminoguanidine increased all antioxidant enzyme activities in both brain and retina in rats exposed to restraint stress compared to rats exposed to restraint stress alone. All VEP components were significantly decreased in AG treated rats exposed to restraint stress compared to rats exposed to restraint stress alone. Our study clearly showed that AG has the potential to prevent changes caused by stress.

Testosterone production in mice lacking inducible nitric oxide synthase expression is sensitive to restraint stress

Immobilization stress (IMO) induces a rapid increase in glucocorticoid secretion [in rodents, corticosterone CORT)] and this is associated with decreased circulating testosterone (T) levels. Nitric oxide (NO), a reactive free radical and neurotransmitter, has been reported to be produced at higher rates in tissues such as brain during stress. The biosynthesis of T is also known to be dramatically suppressed by NO. Specifically, the inducible isoform of nitric oxide synthase (iNOS) was directly implicated in this suppression. To assess the respective roles of CORT and NO in stress-mediated inhibition of T production, adult wild-type (WT) and inducible nitric oxide synthase knockout (iNOS(-/-)) male mice were evaluated. Animals of each genotype were assigned to either basal control or 3-h IMO groups. Basal plasma and testicular T levels were equivalent in both genotypes, whereas testicular weights of mutant mice were significantly higher compared with WT animals. Exposure to 3-h IMO increased plasma CORT and decreased T concentrations in mice of both genotypes. Testicular T levels were also affected by stress in WT and mutant males, being sharply reduced in both genotypes. However, the concentrations of nitrite and nitrate, the stable metabolites of NO measured in testicular extracts, did not differ between control and stressed WT and iNOS(-/-) mice. These results support the hypothesis that CORT, but not NO, is a plausible candidate to mediate rapid stress-induced suppression of Leydig cell steroidogenesis.

Systemic Administration of Alcohol to Adult Rats Inhibits Leydig Cell Activity: Time Course of Effect and Role of Nitric Oxide

BACKGROUND

Alcohol has been shown to interfere with testosterone (T) release from Leydig cells. However, the mechanisms responsible for this phenomenon, which may include decreased activity of the luteinizing hormone-releasing hormone (LHRH)-LH axis, as well as a direct influence of the drug on the testes, are not fully understood. In this work, we investigated the influence of alcohol, administered intragastrically (i.g.) or delivered via vapors, on Leydig cell activity and T release. Leydig cell function was studied by measuring changes in the levels of the steroidogenic proteins steroidogenic acute regulatory (StAR), the peripheral-type benzodiazepine receptor (PBR), and the cytochrome P450 side-chain cleavage enzyme (P450scc). Testosterone release was studied under basal conditions or in response to human chorionic gonadotropin (hCG). Finally, to identify potential factors mediating the influence of alcohol, we measured the testicular variant of the neuronal nitric oxide (NO) synthase (NOS), TnNOS, in semipurified Leydig cells.

METHODS

Adult male Sprague-Dawley rats were either injected with alcohol i.g. once or exposed to alcohol vapors (4 h/d) for 1 or 5 days. Controls received the vehicle (i.g. model) or were kept in boxes through which no vapors were circulated. Following these treatments, one series of experiments was devoted to investigate Leydig cell responsiveness by measuring plasma T levels before or after the intravenous injection of hCG (1 U/kg). In another series of experiments, we used semipurified Leydig cell preparations to measure StAR, PBR, P450scc, and TnNOS by Western blot analysis.

RESULTS

In the i.g. model, the T response to hCG was blunted for 12 hours following alcohol injection, but showed a rebound at 48 hours. Levels of StAR protein and of PBR, but not of P450scc, were significantly decreased within 10 minutes of drug administration. While StAR then remained depressed for 24 hours, PBR values were variable over this time course. By 48 hours, StAR, PBR, and P450scc levels had increased above control values. Both StAR and PBR levels showed correlations with plasma T levels. In the alcohol vapor models, both regimens of the drug also significantly depressed StAR and PBR protein concentrations, blunted the T response to hCG, and did not alter P450scc. Finally, we observed that alcohol delivered i.g. or via vapors up-regulated TnNOS levels in Leydig cells, but that blockade of NO formation failed to restore a normal T response to hCG.

CONCLUSIONS

Collectively, these results suggest that (a) the ability of Leydig cells to release T does not show a simple correlation with changes in StAR, PBR, and P450scc levels; (b) the time course of the alcohol-induced changes were protein-specific; and (c) despite the ability of alcohol to stimulate TnNOS expression, NO does not appear to mediate the inhibitory influence of this drug on testicular steroidogenesis in the models that we studied.

Housing in pyramid counteracts neuroendocrine and oxidative stress caused by chronic restraint in rats

The space within the great pyramid and its smaller replicas is believed to have an antistress effect. Research has shown that the energy field within the pyramid can protect the hippocampal neurons of mice from stress-induced atrophy and also reduce neuroendocrine stress, oxidative stress and increase antioxidant defence in rats. In this study, we have, for the first time, attempted to study the antistress effects of pyramid exposure on the status of cortisol level, oxidative damage and antioxidant status in rats during chronic restraint stress. Adult female Wistar rats were divided into four groups as follows: normal controls (NC) housed in home cage and left in the laboratory; restrained rats (with three subgroups) subject to chronic restraint stress by placing in a wire mesh restrainer for 6 h per day for 14 days, the restrained controls (RC) having their restrainers kept in the laboratory; restrained pyramid rats (RP) being kept in the pyramid; and restrained square box rats (RS) in the square box during the period of restraint stress everyday. Erythrocyte malondialdehyde (MDA) and plasma cortisol levels were significantly increased and erythrocyte-reduced glutathione (GSH) levels, erythrocyte glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities were significantly decreased in RC and RS rats as compared to NC. However, these parameters were maintained to near normal levels in RP rats which showed significantly decreased erythrocyte MDA and plasma cortisol and significantly increased erythrocyte GSH levels, erythrocyte GSH-Px and SOD activities when compared with RS rats. The results showed that housing in pyramid counteracts neuroendocrine and oxidative stress caused by chronic restraint in rats.

Effect of a PCB-based transformer oil on testicular steroidogenesis and xenobiotic-metabolizing enzymes

Pyralene is a PCB-based transformer oil with a unique PCB congener profile when compared to other mixtures. We studied the influence of Pyralene on testicular steroidogenesis and the status of xenobiotic-metabolizing enzymes in the testis and liver of rats during oral exposure (10 and 50 mg/kg body weight, p.o. daily for 1 week) and a 3-week post-treatment recovery period. As expected, Pyralene induced a rapid and sustained increase in mRNA transcripts for CYP1A1 and CYP2B1 in hepatocytes that was associated with a dramatic increase in ethoxyresorufin-O-deethylase (EROD) and pentoxyresorufin-O-deethylase (PROD) activities. Testicular androgenesis and the conversion of progesterone to testosterone in testicular microsomes were bidirectionally affected. An increase in these parameters was observed 24h after the initial administration of Pyralene, followed by inhibition that lasted until the fourth post-treatment day. Expression PCR analysis revealed a significant decrease in 17beta-hydroxysteroid dehydrogenase (17betaHSD) transcript abundance at 48 h after Pyralene administration. In contrast, transcripts for several other steroidogenic enzymes and for testicular CYP1A1, CYP1B1, and CYP2B1 were unaffected under the same conditions. These results in the rat indicate that a sub-chronic exposure to Pyralene disrupted testicular steroidogenesis and suggest the mechanism may involve direct action on the regulation of specific steroidogenic enzymes such as 17betaHSD.

Effect of whole-body 1800MHz GSM-like microwave exposure on testicular steroidogenesis and histology in mice

The aim of our study was to evaluate the possible effects of whole-body 1800 MHz GSM-like microwave exposure on male reproduction. After repeated exposure of mice to microwaves at 0.018-0.023 W/kg whole-body specific energy absorption rate (SAR) an elevated serum testosterone level was measured, but no microwave exposure related histopathological alteration could be detected in the reproductive organs. The in vitro steroidogenic response of 48 h Leydig cell cultures obtained from exposed animals did not differ from the controls, suggesting that Leydig cells were not the primary targets of the applied microwave exposure or direct action of microwaves on Leydig cells was temporary only. In exposed animals the red blood cell count and volume of packed red cells were also increased. Further investigations are required to clarify the mechanism of action of the applied microwave exposure on male mice, as well as to establish the biological significance of the observed phenomena.

Activation of a neural brain-testicular pathway rapidly lowers Leydig cell levels of the steroidogenic acute regulatory protein and the peripheral-type benzodiazepine receptor while increasing levels of neuronal nitric oxide synthase

Activation of a neural brain-testicular pathway by the intracerebroventricular injection of the beta-adrenergic agonist isoproterenol (ISO), the hypothalamic peptide corticotropin-releasing factor (CRF), or alcohol (EtOH) rapidly decreases the testosterone (T) response to human chorionic gonadotropin. To elucidate the intratesticular mechanisms responsible for this phenomenon, we investigated the influence of intracerebroventricular-injected ISO, CRF, or EtOH on levels of the steroidogenic acute regulatory (StAR) protein, the peripheral-type benzodiazepine receptor (PBR), and the cytochrome P450 side-chain cleavage enzyme in semipurified Leydig cells. ISO (10 microg), CRF (5 microg), or EtOH (5 microl of 200 proof, a dose that does not induce neuronal damage nor leaks to the periphery) rapidly decreased StAR and PBR but not cytochrome P450 side-chain cleavage enzyme protein levels. Levels of the variant of the neuronal nitric oxide synthase (nNOS) that is restricted to Leydig cells, TnNOS, significantly increased in response to ISO, CRF, and EtOH over the time course of altered StAR/PBR concentrations. However, pretreatment of the rats with N(w)nitro-arginine methylester, which blocked ISO-induced increases in TnNOS, neither restored the T response to human chorionic gonadotropin nor prevented the decreases in StAR and PBR. These results provide evidence of concomitant changes in Leydig cell StAR and PBR levels in live rats. They also indicate that activation of a neural brain-testicular pathway rapidly decreases concentrations of these steroidogenic proteins while up-regulating testicular NO production. However, additional studies are necessary to elucidate the functional role played by this gas in our model.

Aluminium-induced deterioration in reproductive performance and seminal plasma biochemistry of male rabbits: Protective role of ascorbic acid

Aluminium (Al) has been proposed as an environmental factor that may contribute to some diseases, affect several enzymes and other biomolecules and induced free radical-mediated cytotoxicity. Also, Al induced reproductive toxicity and exerted a significant adverse effect on the steroidogenesis. The antioxidant ascorbic acid (AA) plays an important role in various physiological processes in the body including detoxification of different toxic materials. Therefore, the present investigation aimed to elucidate possible protective effects of AA in alleviating the toxicity of aluminium chloride (AlCl3) on reproductive performance, lipid peroxidation and enzyme activities in seminal plasma of male New Zealand white rabbits. Six rabbits per group were assigned to one of four treatment groups: 0 mg AA and 0 mg AlCl3 /kg body weight (BW) (control); 40 mg AA/kg BW; 34 mg AlCl3 /kg BW; 34 mg AlCl3 plus 40 mg AA/kg BW. Rabbits were orally administered their respective doses every other day for 16 weeks. Results obtained showed that AlCl3 significantly (P<0.05) decreased libido (by increasing the reaction time), ejaculate volume, sperm concentration, total sperm output, sperm motility (%), total motile sperm per ejaculate (TMS), packed sperm volume (PSV), total functional sperm fraction (TFSF), normal and live sperm and semen initial fructose. While initial hydrogen ion concentration (pH) and dead and abnormal sperm were increased (P<0.05). Live body weight (LBW), feed intake (FI) and relative weights of testes (RTW) and epididymis (REW) were significantly (P<0.05) decreased. Concentrations of thiobarbituric acid-reactive substances (TBARS) were significantly (P<0.05) increased in seminal plasma of rabbits treated with AlCl3 compared with control. While, activities of glutathione S-transferase (GST), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and acid phosphatase (AcP) were significantly (P<0.05) decreased. Ascorbic acid alone significantly increased LBW, FI, RTW, REW, semen characteristics and seminal plasma enzymes, and decreased the levels of free radicals. Also, the present study showed that ascorbic acid might be effective in the protection of aluminium-induced reproductive toxicity. It was suggested that AlCl3 exerted a significant adverse effect on reproductive performance of male rabbits. Furthermore, AA could be able to antagonize the toxic effects of AlCl3 and improved semen quality of male rabbit.

Nitric oxide-scavenging activity of polyhydroxylated fullerenol, C60(OH)24

Investigation of the possible nitric oxide-scavenging activity of hydroxylated derivative of fullerene, fullerenol C60(OH)24, demonstrated that it expressed direct scavenging activity toward nitric oxide radical (NO) liberated within solution of sodium nitroprusside (SNP), a well known NO donor. In parallel, pre-treatment (30') with intratesticular injection of fullerenol (60 microg/each testis) prevented NO-induced decrease of catalase, glutathione transferase and glutathione peroxidase activities in the denucleated fraction of interstitial testicular cells of adult rats 2 h after intratesticular injection of SNP (20 microg/each testis). In addition, fullerenol decreased formation of thiobarbituric acid-reactive substances (TBA-RS) with similar efficiency as butylated hydroxy toluen (BHT), a well known antioxidant. Also, fullerenol expressed certain scavenging activity toward superoxide anion (O2-) in xanthine/xanthine oxidase system. In summary, results obtained in this study confirmed free radical-scavenging activity of fullerenol, and according to our knowledge, it is the first evidence of direct NO-quenching activity of hydroxylated C60 derivative in different milieu.

Increased Stress Reactivity as a Possible Factor of Early Degenerative Changes in OXYS Rats

After stress (immobilization in cages) plasma corticosterone level in prematurely aging OXYS rats was higher, while the content of NO metabolites was much lower than in Wistar rats. Stress increased blood pressure in OXYS and Wistar rats, the maximum values were observed in control and stressed OXYS rats. The concentration of reduced glutathione in the brain of OXYS rats was lower than in Wistar rats. After immobilization the concentration of reduced glutathione decreased in animals of both strains. The concentration of oxidized protein increased by 1.5 times only in OXYS rats. SOD activity remained unchanged, but in OXYS rats this parameter was higher than in Wistar rats. It can be hypothesized that high blood pressure, low NO content, high corticosterone concentration, and stress-induced deficiency of the antioxidant system (or combined effects of these factors) contribute to the development of neurodegenerative changes in the brain of OXYS rats.

Testicular oxidative stress. Effects of experimental varicocele in adolescent rats

OBJECTIVE

This present study was undertaken to determine the levels of malondialdehyde (MDA), nitric oxide (NO) and total antioxidant status (TAS) in testes of adolescent rats with experimental bilateral varicocele and to determine the effects of oxidative stress on testis produced by varicocele.

METHODS

6-week-old, male Wistar rats, weighing 146-334 g (228.37 +/- 41.34 g), were randomly allocated into two groups. The first group underwent selective and bilateral partial ligation of the spermatic vein (n = 28), and the second group underwent a sham operation and served as the controls (n = 15). Animals were sacrificed 12 weeks after surgery and dilatation of the spermatic veins was observed in the first study group. Bilateral orchiectomy was performed in all rats, and MDA, NO and TAS levels were measured.

RESULTS

In the study group, the mean MDA (SEM) level was 15.58 +/- 6.07 micromol/g protein, and in the control group, it was 11.59 +/- 3.86 micromol/g protein, respectively; this difference was statistically significant (p < 0.05). The mean NO level was 82.73 +/- 77.84 nmol/g protein in the study group, whereas 28.65 +/- 20.18 nmol/g protein in the control group, this difference was also statistically significant (p < 0.005). The mean TAS levels of the study and control groups were 0.91 +/- 0.32 and 1.78 +/- 0.46 nmol/g tissue, respectively, and this difference was also statistically significant (p < 0.001). But there was no correlation between these three parameters (MDA<-->TAS: r = -0.103, p > 0.05; MDA<-->NO: r = -0.104, p > 0.05; NO<-->TAS: r = -0.123, p > 0.05).

CONCLUSION

These findings suggest that varicocele may change the testicular oxidative status and may play a role in testicular dysfunction that causes infertility.

Treatment with tetrahydrobiopterin reduces blood pressure in male SHR by reducing testosterone synthesis

Treatment with tetrahydrobiopterin (BH(4)) reduces blood pressure in spontaneously hypertensive rats (SHR). In the present study, we tested the hypothesis that chronic BH(4) reduces blood pressure in male SHR by reducing testosterone biosynthesis mediated by increasing nitric oxide (NO). Male SHR, aged 17-18 wk, intact or castrated, were treated for 1 wk with BH(4) (20 mg.kg(-1).day(-1) ip). After 1 wk, mean arterial pressure (MAP), serum testosterone, and nitrate/nitrite excretion (NO(x)) were measured. MAP was significantly higher in intact males than castrated males (179 +/- 2 vs. 155 +/- 4 mmHg, P < 0.001). In intact males, BH(4) caused a 17% reduction in MAP (148 +/- 2 mmHg), had no effect on NO(x), and reduced serum testosterone by 85% (24.09 +/- 2.37 vs. 3.72 +/- 0.73 ng/dl; P < 0.001). In castrated males, BH(4) had no effect on MAP (152 +/- 5 mmHg) but increased NO(x) by 38%. When castrated males were supplemented with testosterone, MAP increased to the same level as in intact males (180 +/- 7 mmHg), and BH(4) had no effect on MAP (182 +/- 7 mmHg) or NO(x). NO has been shown to decrease testosterone biosynthesis. Chronic sodium nitrite (70 mg.kg(-1).day(-1) x 1 wk) decreased MAP in intact males (150 +/- 4 mmHg) but had no effect on serum testosterone (21.46 +/- 3.08 ng/dl). The data suggest that BH(4) reduces testosterone synthesis and thereby reduces MAP in male SHR, an androgen-dependent model of hypertension. The mechanism(s) by which BH(4) reduces serum testosterone levels are not clear, but the data do not support a role for NO as a mediator.