INHIBITORY ACTIONS OF LEAD ON STEROIDOGENESIS IN MA-10 MOUSE LEYDIG TUMOR CELLS

Melatonin or vitamin C attenuates lead acetate-induced testicular oxidative and inflammatory damage in mice by inhibiting oxidative stress mediated NF-κB signaling

Lead (Pb) acts as an environmental endocrine disruptor and has negative effects in animals; excessive accumulation of lead causes reproductive dysfunction in male animals. Oxidative stress plays a vital role in Pb-induced injury. However, the mechanisms underlying chronic testicular toxicity of Pb remain unclear. In this study, we aimed to determine the effects of lead acetate on reproductive function in male mice, identify the underlying mechanisms, and test counter measures to alleviate the toxic effects. Male mice were dosed with lead acetate (500 mg/L) in free drinking water for 12 weeks, and administered melatonin (5 mg/kg) or vitamin C (500 mg/kg) by intraperitoneal injection. Blood from the eyeball, testicles, and sperm from the caudal epididymis were collected after 12 weeks and analyzed. Pb exposure reduced sperm count and motility, increased sperm malformation (P < 0.01), disrupted testicular morphology and structure, and decreased the expression of steroid hormone synthesis-related enzymes and serum testosterone concentration (P < 0.01). Pb also increased the number of inflammatory cells and the levels of the pro-inflammatory cytokines TNF-α and IL-6 (P < 0.01), and activated NF-κB signaling. Furthermore, the ROS yield and oxidation indicators LPO and MDA were significantly increased (P < 0.01), and the antioxidant indicators T-AOC, SOD, and GSH were significantly reduced (P < 0.01). Treatment with melatonin or vitamin C reversed the effects of lead acetate; vitamin C was more effective in restoring SOD activity (P < 0.01) and enhancing ZO-1 protein levels (P < 0.01). Thus, long-term exposure to lead acetate at low concentrations could adversely affect sperm quality and induce inflammatory damage by oxidative stress mediated NF-κB signaling. Vitamin C could act as a protective agent and improve reproductive dysfunction in male animals after lead accumulation.

Naringenin alleviate reproductive toxicity evoked by lead acetate via attenuation of sperm profile and biochemical alterations in male Wistar rat: Involvement of TGFβ/AKT/mTOR pathway

Exposure to Lead -causes testicular dysfunction through oxidative stress, inflammation, and apoptosis; however, naringenin (NGN) therapeutic impact against lead-evoked testicular dysfunction remains elusive. Herein, the point of the study was to examine the defensive impact of NGN on testicular dysfunction initiated by lead. Seventy-Two male Wistar rats were allotted into nine groups; control group, drug control groups, lead acetate group, as well as NGN treated groups (10, 25, and 50 mg/kg) respectively, given 5 days before lead acetate treatment. The result showed clearly the impact of lead on reduced sperm count, sperm motility as well as serum testosterone and LH levels. Additionally, it caused a significant rise in testicular inflammatory markers TNF-α, IL-1β, and TGFβ, effects that were accompanied by a reduction of AKT and mTOR levels. Lead acetate also caused degenerative changes in the testis, atrophy, and loss of spermatogenic series. Our findings revealed that NGN in a dose-dependent manner improved spermiotoxicity induced by lead acetate via restoration of the testicular function, preservation of spermatogenesis, halting inflammatory cytokines along with the enhancement of germ cell survival using upregulation of AKT/mTOR expressions. The present study discloses that NGN suppresses lead acetate toxicity that is involved in the antioxidant effect in a dose-dependent manner, besides its anti-inflammatory property.

Glycine protects the male reproductive system against lead toxicity via alleviating oxidative stress, preventing sperm mitochondrial impairment, improving kinematics of sperm, and blunting the downregulation of enzymes involved in the steroidogenesis

Lead (Pb) is a highly toxic heavy metal widely dispersed in the environment because of human industrial activities. Many studies revealed that Pb could adversely affect several organs, including the male reproductive system. Pb-induced reproductive toxicity could lead to infertility. Thus, finding safe and clinically applicable protective agents against this complication is important. It has been found that oxidative stress plays a fundamental role in the pathogenesis of Pb-induced reprotoxicity. Glycine is the simplest amino acid with a wide range of pharmacological activities. It has been found that glycine could attenuate oxidative stress and mitochondrial impairment in various experimental models. The current study was designed to evaluate the role of glycine in Pb-induced reproductive toxicity in male mice. Male BALB/c mice received Pb (20 mg/kg/day; gavage; 35 consecutive days) and treated with glycine (250 and 500 mg/kg/day; gavage; 35 consecutive days). Then, reproductive system weight indices, biomarkers of oxidative stress in the testis and isolated sperm, sperm kinetic, sperm mitochondrial indices, and testis histopathological alterations were monitored. A significant change in testis, epididymis, and Vas deferens weight was evident in Pb-treated animals. Markers of oxidative stress were also significantly increased in the testis and isolated sperm of the Pb-treated group. A significant disruption in sperm kinetic was also evident when mice received Pb. Moreover, Pb exposure caused significant deterioration in sperm mitochondrial indices. Tubular injury, tubular desquamation, and decreased spermatogenic index were histopathological alterations detected in Pb-treated mice. It was found that glycine significantly blunted oxidative stress markers in testis and sperm, improved sperm mitochondrial parameters, causing considerable higher velocity-related indices (VSL, VCL, and VAP) and percentages of progressively motile sperm, and decreased testis histopathological changes in Pb-exposed animals. These data suggest glycine as a potential protective agent against Pb-induced reproductive toxicity. The effects of glycine on oxidative stress markers and mitochondrial function play a key role in its protective mechanism.

Antioxidative, anti-inflammatory and anti-apoptotic action of ellagic acid against lead acetate induced testicular and hepato-renal oxidative damages and pathophysiological changes in male Long Evans rats

Lead (Pb), is an environmental toxicant, causes multi-organ dysfunction including reproductive impairments. This study designed to investigate the prospective antioxidative, anti-inflammatory and anti-apoptotic effects of ellagic acid (EA) on Pb-mediated testicular and hepato-renal toxicity. Four experimental groups of five male Long-Evans rats each were used: control, Pb (60 mg/kg), EA (30 mg/kg), and Pb + EA groups. All groups were given their respective treatment orally for 30 days. Pb exposure altered body and organs weight, food and water consumption, rectal temperature, Pb residue levels in tissues, liver and kidney function, sperm quality parameters, serum metabolic and hematology profiles, and impaired the oxidative/antioxidative balance in the testicular and hepato-renal tissue, as shown by the decreased antioxidant proteins (superoxide dismutase, catalase, glutathione peroxidase, and reduced glutathione) and increased the oxidative (MDA, lipid hydroperoxides, conjugated dienes, protein carbonyl, fragmented DNA and GSH:GSSG ratio) stress and inflammatory (IL-1, IL-6, TNF-α, prostaglandin, LTB4, NO, myeloperoxidase, LDH) markers. Moreover, a dysregulation in the stress response (HSP-70) and apoptotic-regulating proteins (BAX, BCL-2, and active Caspase-3) were recorded upon Pb exposure. Remarkably, EA oral administration reduced the Pb residue levels in tissues, improved the liver and kidney function, revived the spermatogenesis and sperm quality, restored redox homeostasis, suppressed the oxidative stress, inflammatory and apoptotic responses in the liver, kidney and testis tissue. Our findings point out that EA can be used as a phyto-chelator to overcome the adverse effects of Pb exposure due to its potent antioxidant, anti-inflammatory, and anti-apoptotic effects.

Umbelliferone Inhibits Spermatogenic Defects and Testicular Injury in Lead-Intoxicated Rats by Suppressing Oxidative Stress and Inflammation, and Improving Nrf2/HO-1 Signaling

INTRODUCTION

Lead (Pb) is an environmental toxic metal that threatens human health. Umbelliferone (UMB) is a coumarin with known medicinal and protective properties against cytotoxicity. This study explored the ameliorative effect of UMB against Pb-induced testicular toxicity in rats, focusing on steroidogenesis, oxidative stress and inflammation.

MATERIALS AND METHODS

Rats received lead acetate (50 mg/kg) and UMB (25, 50 or 100 mg/kg) via oral gavage for 4 weeks.

RESULTS

Pb-intoxicated rats exhibited testicular tissue injury and decreased serum levels of LH, FSH and testosterone. The count, viability, motility and normal morphology of the sperms were decreased accompanied with downregulated steroidogenesis markers in Pb-induced group. UMB prevented testicular injury, increased serum levels of LH, FSH and testosterone, upregulated steroidogenesis markers and improved the semen quality. In addition, UMB attenuated oxidative stress and oxidative DNA damage, downregulated the expression of pro-inflammatory mediators and Bax, boosted antioxidant defenses and Bcl-2, and upregulated Nrf2/HO-1 signaling in Pb-intoxicated rats.

CONCLUSION

UMB prevents Pb-induced testicular injury by suppressing oxidative damage, inflammation and cell death, and boosting antioxidant defenses, Nrf2/HO-1 signaling and pituitary-gonadal axis. Thus, UMB may represent a protective and cost-effective agent against Pb testicular toxicity, pending further investigations to elucidate other underlying mechanisms.

Impact of Coenzyme Q10 Administration on Lead Acetate-Induced Testicular Damage in Rats

Exposure to lead (Pb) causes multiorgan dysfunction including reproductive impairments. Here, we examined the protective effects of coenzyme Q10 (CoQ10) administration on testicular injury induced by lead acetate (PbAc) exposure in rats. This study employed four experimental groups (n = 7) that underwent seven days of treatment as follows: control group intraperitoneally (i.p.) treated with 0.1 ml of 0.9% NaCl containing 1% Tween 80 (v : v), CoQ10 group that was i.p. injected with 10 mg/kg CoQ10, PbAc group that was i.p. treated with PbAc (20 mg/kg), and PbAc+CoQ10 group that was i.p. injected with CoQ10 2 h after PbAc. PbAc injection resulted in increasing residual Pb levels in the testis and reducing testosterone, luteinizing hormone, and follicle-stimulating hormone levels. Additionally, PbAc exposure resulted in significant oxidative damage to the tissues on the testes. PbAc raised the levels of prooxidants (malondialdehyde and nitric oxide) and reduced the amount of endogenous antioxidative proteins (glutathione and its derivative enzymes, catalase, and superoxide dismutase) available in the cell. Moreover, PbAc induced the inflammatory response as evidenced by the upregulation of inflammatory mediators (tumor necrosis factor-alpha and interleukin-1 beta). Further, PbAc treatment induced apoptosis in the testicular cells, as indicated by an increase in Bax and caspase 3 expression, and reduced Bcl2 expression. CoQ10 supplementation improved testicular function by inhibiting Pb accumulation, oxidative stress, inflammation, cell death, and histopathological changes following PbAc exposure. Our findings suggest that CoQ10 can act as a natural therapeutic agent to protect against the reproductive impairments associated with PbAc exposure.

Effects of aqueous extract of Moringa oleifera seed on cadmium-induced reproductive toxicity in male Wistar rats

Background

Moringa oleifera seeds have been reported to increase sexual activity of male rats but its mechanism of action remains unknown.

Objective

Cadmium is a heavy metal that induces reproductive toxicity. To elucidate its possible mechanisms of action, the effects of aqueous extract of Moringa seeds (AEMS) on Cadmium-induced reproductive damage were investigated.

Methods

Thirty male rats (180–200g, n=5) were grouped as follows: Control, Cadmium (2mg/kg), AEMS (100 and 500mg/kg), Cadmium+100mg/kg AEMS and Cadmium+500mg/kg AEMS. Single intraperitoneal dose of Cadmium was administered while AEMS was given daily (p.o) for 6 weeks and thereafter sacrificed by cervical dislocation. Sperm variables were examined microscopically while serum was analysed for sex hormones and antioxidants, testicular and epididymal total protein from tissue homogenate. Data were analysed using Students t-test and ANOVA.

Results

Cadmium caused significant decrease in sperm variables. The AEMS decreased sperm motility, count and testosterone. These declines were dose dependent. Total testicular protein was significantly lowered by AEMS but total epididymal protein was not affected. Serum catalase and SOD was reduced by AEMS while MDA increased.

Conclusion

Moringa seeds may exhibit male reproductive toxicity, as observed from its deleterious effect on androgen and sperm variables. It failed to prevent cadmium-induced alteration in reproductive variables and serum antioxidants.

Cross-species coherence in effects and modes of action in support of causality determinations in the U.S. Environmental Protection Agency's Integrated Science Assessment for Lead

The peer-reviewed literature on the health and ecological effects of lead (Pb) indicates common effects and underlying modes of action across multiple organisms for several endpoints. Based on such observations, the United States (U.S.) Environmental Protection Agency (EPA) applied a cross-species approach in the 2013 Integrated Science Assessment (ISA) for Lead for evaluating the causality of relationships between Pb exposure and specific endpoints that are shared by humans, laboratory animals, and ecological receptors (i.e., hematological effects, reproductive and developmental effects, and nervous system effects). Other effects of Pb (i.e., cardiovascular, renal, and inflammatory responses) are less commonly assessed in aquatic and terrestrial wildlife limiting the application of cross-species comparisons. Determinations of causality in ISAs are guided by a framework for classifying the weight of evidence across scientific disciplines and across related effects by considering aspects such as biological plausibility and coherence. As illustrated for effects of Pb where evidence across species exists, the integration of coherent effects and common underlying modes of action can serve as a means to substantiate conclusions regarding the causal nature of the health and ecological effects of environmental toxicants.

THE EFFECTS OFTREMELLA AURANTIAON TESTOSTERONE AND CORTICOSTERONE PRODUCTIONS IN NORMAL AND DIABETIC RATS

Tremella aurantia (TA) has been traditionally used as food and crude medicine in Chinese society. The polysaccharide isolated from the fruiting bodies of TA exhibits significant hypoglycemic activity in diabetic mouse models of insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus (NIDDM). Diabetes will cause sexual dysfunction in patients. In the present study, we examined if the treatment of TA on IDDM and NIDDM rats will restore steroidogenesis and then the reproductive function. The fruiting bodies (FB), mycelium (TM) and polysaccharide (GX) of TA were fed to the IDDM and NIDDM rats, and testosterone and corticosterone levels in plasma, the weight of steroidogenic organs, and the expression of steroidogenic acute regulatory (StAR) protein and P450scc enzyme were determined. Plasma testosterone productions were significantly suppressed with the feeding of FB or TM in normal rat (p < 0.05). Testosterone productions were also significantly suppressed in IDDM diabetes rats (p <0.05), and FB or TM could not restore the inhibitory effects (p > 0.05). There was no significant difference of the testosterone production between normal and NIDDM rats (p > 0.05). In plasma corticosterone production, there were no differences among control, FB- or TM-fed normal rats (p > 0.05). Corticosterone levels were reduced in IDDM rats compared to control, and FB or TM could restore its level. Corticosterone levels were induced in NIDDM rats compared to control (p <0.05), but FB, TM or GX significantly brought the corticosterone back (p < 0.05) to the control levels. Considering steroidogenic organs, IDDM rats with or without TA treatments had heavier testis and adrenal glands, but not epididymis, than normal rats with or without TA treatments. There were no effects of TA on the weight of steroidogenic organs among normal and NIDDM rats. However, GX feeding in NIDDM rat had lesser testis weight compared to NIDDM rats. The expression of StAR protein and P450scc enzyme were not different among groups in IDDM and NIDDM rats. Plasma testosterone productions were suppressed in normal rats with the feeding of TA (FB and TM). IDDM rats did have lower testosterone, but not in NIDDM, and FB or TM could not restore the inhibitory effects. The induction of IDDM or NIDDM rats did affect steroidogenesis and steroidogenic organ weights, and the feeding of TA had different effects on steroidogenesis in different types of diabetic rats.

Plasma 17-alpha-OH-progesterone in male workers exposed to traffic pollutants

The aim of the study is to evaluate if the occupational exposure to urban pollutants could cause alterations on 17-alfa-hydroxy-progesterone plasma levels and related diseases in male traffic policemen. 17-alpha-OH-P is synthesized in Leydig cells and in adrenals; it influences spermiogenesis, acrosoma reaction, testosterone biosynthesis, blocking of gonadotropin secretion; it regulates learning, memory and sleep. After excluding principal confounding factors, i.e., rotating or night shifts, exposure to solvents, paints and pesticides during time-off and smoking, traffic policemen were matched with controls by age, working life and drinking habit. Finally, 112 traffic policemen and 112 controls were included in the study. In traffic policemen 17-alpha-OH-P mean values were significantly higher vs. controls. The distribution of 17-alpha-OH-P values in both groups was significant. An increased frequency of fertility disorders referred to the questionnaire items were found in traffic policemen vs. controls, but the difference was not significant. The occupational exposure to low doses of chemical urban stressor, interacting with and adding to the psychosocial ones, could alter plasma 17-alpha-OH-P concentrations in traffic policemen vs. controls. 17-alpha-OH-P could be used as an early biological marker, even before the onset of the reproductive and mental health diseases.

Lepidium meyenii (Maca) reversed the lead acetate induced—Damage on reproductive function in male rats

Rats were treated with 0, 8, 16 and 24 mg/kg of lead acetate (LA) (i.p.) for 35 days with or without Maca. Maca was co-administrated orally from day 18 to day 35. The lengths of stages of the seminiferous epithelium were assessed by transillumination. Also, sex organ weights, testicular and epididymal sperm count, sperm motility, daily sperm production, sperm transit rate and serum testosterone levels were measured. Lead acetate treatment resulted in a dose-response reduction of lengths of stages VIII and IX-XI, and serum testosterone levels. However, rats treated with 8 and 16 mg/kg but not 24 mg/kg of lead acetate showed a low number of testicular spermatids, low daily sperm production (DSP) and low epididymal sperm count. Administration of Maca to rats treated with lead acetate resulted in higher lengths of stages VIII and IX-XI with respect to lead acetate-treated rats. Moreover, treatment with Maca to lead acetate-treated rats resulted in lengths of stages VIII and IX-XI similar to the control group. Maca administration also reduced the deleterious effect on DSP caused by lead acetate treatment. Maca prevented LA-induced spermatogenic disruption in rats and it may become in a potential treatment of male infertility associated with lead exposure.

Simultaneous effect of lead and cadmium on granulosa cells: a cellular model for ovarian toxicity

Lead (Pb) and cadmium (Cd) are known reproductive toxicants, which accumulate in granulosa cells of the ovary. Female Charles foster rats were treated with sodium acetate (control), lead acetate and cadmium acetate either alone or in combination at a dose 0.05 mg/kg body weight intra-peritoneally for 15 days daily. Animals were killed at proestrous stage and granulosa cells were isolated from the ovaries. Binding of (125)I-luteinizing hormone ((125)I-LH), (125)I-follicle stimulating hormone ((125)I-FSH) and 17beta-hydroxysteroid dehydrogenase activity were measured. As these receptors are localized on the surface of the cell membrane, we also estimated the membrane parameters of these cells. Our results demonstrated that both lead and cadmium caused a significant reduction in gonadotropin binding, which altered steroidogenic enzyme activity of granulosa cells. These changes exhibited a positive correlation with membrane changes of the granulosa cells.