Link between low-dose environmentally relevant cadmium exposures and asthenozoospermia in a rat model

Targeting TLR4/NF-κB signaling, oxidative stress, and apoptosis by farnesol mitigates cadmium-induced testicular toxicity in rats

Cadmium (Cd) is a highly toxic heavy metal, and its detrimental effects on reproductive health pose a significant risk to the general population. Farnesol (FAR), a sesquiterpene alcohol, exhibits anti-inflammatory, antioxidant, and anticancer properties. This study investigated the protective effects of FAR against Cd-induced testicular toxicity, focusing on its antioxidant and anti-inflammatory mechanisms. Rats were randomly divided into four experimental groups: control, FAR (10 mg/kg), Cd (1.2 mg/kg), and Cd + FAR. Cd administration caused testicular tissue damage, altered hormone levels, oxidative stress and apoptosis, upregulated TLR4/NF-κB signaling and diminished antioxidants. FAR ameliorated gonadotropins and testosterone, prevented tissue damage, and attenuated oxidative stress. Additionally, FAR significantly attenuated the inflammatory response triggered by Cd, as evidenced by reduced levels of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) and suppression of the TLR4/NF-κB signaling pathway. FAR inhibited testicular apoptosis by upregulating the anti-apoptotic protein Bcl-2 and downregulating the pro-apoptotic markers Bax and caspase-3. These results suggest that FAR mitigates Cd-induced testicular toxicity through upregulation of antioxidants, suppression of TLR4/NF-κB signaling, and inhibition of apoptotic pathways. Thus, FAR represents a promising therapeutic agent for protecting against Cd-induced reproductive damage.

Oral Supplementation with Modified Natural Clinoptilolite Protects Against Cadmium Toxicity in ICR (CD-1) Mice

For the first time, this study investigates in vivo the potential of Na-modified natural clinoptilolite to mitigate cadmium toxicity in ICR mice, a model relevant to human health. We enhanced natural clinoptilolite to improve its cadmium (Cd) exchange capacity. Mice were exposed to environmentally realistic cadmium nitrate Cd(NO3)2 doses in their drinking water. The detoxification efficacy of the mineral was evaluated over 45 days in four groups: control (no supplementation), Cd(NO3)2 only, clinoptilolite only, and a combination of Cd(NO3)2 and clinoptilolite. We assessed Cd bioaccumulation in the liver and kidneys, genotoxicity (micronucleus assay), hematological parameters, and oxidative stress markers. Cd exposure resulted in significant bioaccumulation, reduced growth, changes in erythrograms, DNA damage, and oxidative stress. Mice receiving clinoptilolite alone showed a significant increase in body mass. Modified clinoptilolite led to a nearly 48% reduction in Cd accumulation and a 30% increase in Cd excretion in the Cd-plus-clinoptilolite group compared to the Cd-only group. Erythrogram and leukogram parameters returned to near-normal levels, with reductions in malondialdehyde (MDA) and increases in glutathione (GSH) observed by the end of the experiment. No elevated levels of micronuclei were found following clinoptilolite supplementation. These results suggest that modified clinoptilolite may be a cost-effective detoxifier in Cd-polluted regions.

Detrimental effects of cadmium on male infertility: A review

Infertility has become a serious health and socio-economic-psychological problem globally. The harmful role of trace metals in male infertility is recognized but still not sufficiently explained. Herein, a comprehensive review was conducted to elucidate the detrimental role of cadmium (Cd) on male infertility, particularly on infertility with unknown (idiopathic) causes. Peer-reviewed studies from 2000 to 2024 dealing with seminal plasma and blood Cd levels of fertile and infertile men were retrieved were interrogated with regard to strict inclusion/exclusion criteria, and then were thoroughly reviewed and analyzed. Another aim of this review was to indicate the potential effects of Cd on changes in seminogram findings. A median range of seminal plasma Cd levels from 0.2 to 1.5 µg/L can be considered safe for men's fertility. This review strongly implies that Cd levels were notably higher in seminal plasma of infertile cases than controls. The review's data also indicate that exposure to tobacco smoke is a major source of elevated seminal and blood Cd levels in infertile men. Newer research points to the importance of Cd in lower levels from the environment on changes in seminogram findings, primarily count, motility of spermatozoa, and their morphology. Overall, this review implies that seminal plasma Cd levels could be a good indicator of semen quality. However, new, in-depth studies are needed to confirm or reject the causal relationship of Cd with male infertility.

Melatonin counteracts cadmium-induced rat testicular toxicity via the mechanistic target rapamycin (mTOR) pathway

The protective action of melatonin (MLT) against the harmful effects of cadmium (Cd) on testicular activity in rats has been documented previously; however, the involved molecular mechanisms have yet to be elucidated. Herein, we investigate the involvement of the mammalian target of rapamycin (mTOR) on the ability of MLT to counteract the damage induced by Cd on the rat testicular activity. Our study confirmed that Cd has harmful effects on the testes of rats and the protective action exerted by MLT. We reported, for the first time, that the addition of rapamycin (Rapa), a specific mTOR inhibitor, to animals co-treated with Cd and MLT completely abolished the beneficial effects exerted by MLT, indicating that the mTOR pathway partially modulates its helpful effects on Cd testicular toxicity. Interestingly, Rapa-alone treatment, provoking mTOR inhibition, produced altered morphological parameters, increased autophagy of germ and somatic cells, and reduced serum testosterone concentration. In addition, mTOR inhibition also reduced protein levels of markers of steroidogenesis (3β-Hydroxysteroid dehydrogenase) and blood-testis barrier integrity (occludin and connexin 43). Finally, Rapa altered sperm parameters as well as the ability of mature spermatozoa to perform a proper acrosome reaction. Although further investigation is needed to better clarify the molecular pathway involved in MLT action, we confirm that MLT alleviating Cd effects can be used as a supplement to enhance testicular function and improve male gamete quality.

Dietary fat and fatty acid consumptions and the odds of asthenozoospermia: a case-control study in China

STUDY QUESTION

Are dietary fat and fatty acid (FA) intakes related to the odds of asthenozoospermia?

SUMMARY ANSWER

Plant-based fat consumption was associated with decreased asthenozoospermia odds, while the consumption of animal-based monounsaturated fatty acid (MUFA) was positively related to asthenozoospermia odds.

WHAT IS KNOWN ALREADY

Dietary fat and FA are significant ingredients of a daily diet, which have been demonstrated to be correlated to the reproductive health of men. However, to date, evidence on fat and FA associations with the odds of asthenozoospermia is unclear.

STUDY DESIGN SIZE DURATION

The hospital-based case-control study was performed in an infertility clinic from June 2020 to December 2020. Briefly, 549 asthenozoospermia cases and 581 controls with normozoospermia were available for final analyses.

PARTICIPANTS/MATERIALS SETTING METHODS

We collected dietary data through a verified food frequency questionnaire of 110 food items. Asthenozoospermia cases were ascertained according to the World Health Organization guidelines. To investigate the correlations of dietary fat and FA consumptions with the odds of asthenozoospermia, we calculated the odds ratios (ORs) and corresponding 95% CIs through unconditional logistic regression models.

MAIN RESULTS AND THE ROLE OF CHANCE

Relative to the lowest tertile of consumption, the highest tertile of plant-based fat intake was inversely correlated to the odds of asthenozoospermia (OR = 0.68, 95% CI = 0.50-0.91), with a significant dose-response relation (OR = 0.85, 95% CI = 0.75-0.97, per standard deviation increment). Inversely, animal-based MUFA intake (OR = 1.49, 95% CI = 1.04-2.14) was significantly correlated to increased odds of asthenozoospermia, and an evident dose-response relation was also detected (OR = 1.24, 95% CI = 1.05-1.45, per standard deviation increment). Subgroup analyses showed similar patterns of associations to those of the primary results. Moreover, we observed significant interactions on both multiplicative and additive scales between animal-based MUFA and cigarette smoking.

LIMITATIONS REASONS FOR CAUTION

Selection bias and recall bias were unavoidable in any of the observational studies. As we failed to obtain the information of trans-fatty acid (TFA) consumption, the relation of TFA intake and asthenozoospermia odds was unclear.

WIDER IMPLICATIONS OF THE FINDINGS

This study indicated that different sources of fat and FAs might exert different effects on the etiology of asthenozoospermia, and cigarette smoking could exacerbate the adverse effect of high animal-based MUFA intake on asthenozoospermia. Our findings provide novel evidence pertaining to the fields of prevention of asthenozoospermia through decreasing animal-derived fat and FA consumptions and smoking cessation.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the JieBangGuaShuai Project of Liaoning Province, Natural Science Foundation of Liaoning Province, Clinical Research Cultivation Project of Shengjing Hospital, and Outstanding Scientific Fund of Shengjing Hospital. All authors have no conflict of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Evidence of the protective role of D-Aspartate in counteracting/preventing cadmium-induced oxidative stress in the rat testis

Cadmium (Cd), by producing oxidative stress and acting as an endocrine disruptor, is known to cause severe testicular injury, documented by histological and biomolecular alterations, such as decreased serum testosterone (T) level and impairment of spermatogenesis. This is the first report on the potential counteractive/preventive action of D-Aspartate (D-Asp), a well-known stimulator of T biosynthesis and spermatogenesis progression by affecting hypothalamic-pituitary-gonadal axis, in alleviating Cd effects in the rat testis. Our results confirmed that Cd affects testicular activity, as documented by the reduction of serum T concentration and of the protein levels of steroidogenesis (StAR, 3β-HSD, and 17β-HSD) and spermatogenesis (PCNA, p-H3, and SYCP3) markers. Moreover, higher protein levels of cytochrome C and caspase 3, together with the number of cells positive to TUNEL assay, indicated the intensification of the apoptotic process. D-Asp administered either simultaneously to Cd, or for 15 days before the Cd-treatment, reduced the oxidative stress induced by the metal, alleviating the consequent harmful effects. Interestingly, the preventive action of D-Asp was more effective than its counteractive effect. A possible explanation is that giving D-Asp for 15 days induces its significant uptake in the testes, reaching the concentrations necessary for optimum function. In summary, this report highlights, for the first time, the beneficial role played by D-Asp in both counteracting/preventing the adverse Cd effects in the rat testis, strongly encouraging further investigations to consider the potential value of D-Asp also in improving human testicular health and male fertility.

Dietary trends and the decline in male reproductive health

Over the twentieth century, male reproductive health has suffered a substantial decline, as evidenced by decreases in sperm counts and testosterone levels and increases in reproductive pathologies. At the same time, the prevalence of chronic diseases such as obesity, diabetes, and metabolic syndrome has risen dramatically. Metabolic and reproductive health are highly interconnected, suggesting that their respective trends are intertwined and, given the timeframe of such trends, environmental and not genetic factors are most likely to be the primary causes. Industrialization, which began in Europe in the mid-eighteenth century, has resulted in profound changes to our diet, lifestyle, and environment, many of which are causal factors in the rise in chronic diseases. Industrialization results in a nutrition transition from an agricultural unprocessed to a modern processed diet, incorporating increases in sugar, vegetable oils, ultra-processed foods, linoleic acid, trans-fats, and total energy. This dietary shift has incurred numerous adverse effects on metabolic and reproductive health, characterized by chronic inflammation, oxidative stress, and insulin resistance. Moreover, these effects appear to multiply across subsequent generations via epigenetic inheritance. Men's fertility is markedly affected by obesity and diabetes, with an increase in total energy via processed food intake arguably being the key factor driving the diabesity pandemic. In contrast, wholefoods rich in micronutrients and phytonutrients support male fertility and a healthy body weight. Therefore, men wanting to maximize their fertility should consider making positive dietary changes, such as replacing processed foods with unprocessed foods that support metabolic and reproductive health.

Mechanisms of Cadmium-Induced Testicular Injury: A Risk to Male Fertility

Cadmium is a heavy toxic metal with unknown biological functions in the human body. Over time, cadmium accretion in the different visceral organs (liver, lungs, kidney, and testis) is said to impair the function of these organs, which is associated with a relatively long biological half-life and a very low rate of excretion. Recently studies have revealed that the testes are highly sensitive to cadmium. In this review, we discussed the adverse effect of cadmium on the development and biological functions of the testis. The Sertoli cells (SCs), seminiferous tubules, and Blood Testis Barrier are severely structurally damaged by cadmium, which results in sperm loss. The development and function of Leydig cells are hindered by cadmium, which also induces Leydig cell tumors. The testis's vascular system is severely disturbed by cadmium. Cadmium also perturbs the function of somatic cells and germ cells through epigenetic regulation, giving rise to infertile or sub-fertile males. In addition, we also summarized the other findings related to cadmium-induced oxidative toxicity, apoptotic toxicity, and autophagic toxicity, along with their possible mechanisms in the testicular tissue of different animal species. Consequently, cadmium represents a high-risk factor for male fertility.

Short total sleep duration and poor sleep quality might be associated with asthenozoospermia risk: A case-control study

Sleep has been related to a variety of health outcomes. However, no association between sleep and asthenozoospermia has been reported. The aim of this study is to first investigate the relationship between sleep status and asthenozoospermia risk. A case-control study, including 540 asthenozoospermia cases and 579 controls, was performed from June 2020 to December 2020 in the infertility clinic from Shengjing Hospital of China Medical University. Data on sleep status were collected by Pittsburgh sleep quality index questionnaires and asthenozoospermia was diagnosed based on the World Health Organization guidelines. Odds ratio (OR) with 95% confidence interval (95% CI) was calculated by logistic regression analysis to assess the aforementioned association. Results of this study demonstrated that compared with total sleep duration of 8–9 h/day, < 8 h/day was related to asthenozoospermia risk (OR: 1.44, 95% CI: 1.05–1.99); compared to good sleep quality, poor sleep quality was associated with asthenozoospermia risk (OR: 1.35; 95% CI: 1.04–1.77). There were multiplicative model interaction effects between sleep quality and tea drinking (p = 0.04), rotating night shift work (p < 0.01) on asthenozoospermia risk. However, we failed to detect any associations between night sleep duration, daytime napping duration, night bedtime, wake-up time, sleep pattern and asthenozoospermia risk. In conclusion, short total sleep duration and poor sleep quality might be related to asthenozoospermia risk. Further well-designed prospective studies are warranted to confirm our findings.

Impacts of cadmium on male fertility: Lessons learnt so far

Cadmium (Cd) is one of the most dangerous heavy metals in the world. Globally, toxicities associated with cadmium and its attendant negative impact on humans and animals cannot be under-estimated. Cd is a heavy metal, and people are exposed to it through contaminated foods and smoking. Cd exerts its deleterious impacts on the testes (male reproductive system) by inducing oxidative stress, spermatogenic cells apoptosis, testicular inflammation, decreasing androgenic and sperm cell functions, disrupting ionic homeostasis, pathways and epigenetic gene regulation, damaging vascular endothelium and blood testes barrier. In association with other industrial by-products, Cd has been incriminated for the recent decline of male fertility rate seen in both man and animals. Understanding the processes involved in Cd-induced testicular toxicity is vital for the innovation of techniques that will help ameliorate infertility in males. In this review, we summed up recent studies on the processes of testicular toxicity and male infertility due to Cd exposure. Also, the usage of different compounds including phytochemicals, and plant extracts to manage Cd reprotoxicity will be reviewed.

Cadmium induces apoptosis and autophagy in swine small intestine by downregulating the PI3K/Akt pathway

Cadmium (Cd) is an environmental contaminant, which is potentially toxic. It is well known that Cd can accumulate in the liver and kidney and cause serious damage. However, few studies have investigated the mechanism of intestinal damage induced by Cd in swine. Here, we established Cd poisoning models in vivo and in vitro to explore the mechanism of intestinal injury induced by Cd in swine. The morphology of intestinal tissue cells was observed by TUNEL staining and electron microscopy, and the morphology of IPEC-J2 cells was observed by flow cytometry, Hoechst staining, and MDC staining. Cell morphological observations revealed that Cd treatment induced ileal apoptosis and autophagy. The effects of Cd on the PI3K/Akt pathway, as well as on apoptosis and autophagy-related protein expression in intestinal cells, were analyzed by western blot (WB) and the expression of mRNA was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The results showed that Cd induced autophagy by increasing the levels of autophagy markers Beclin1, Autophagy-associated gene 5 (ATG5), Autophagy-associated gene 16 (ATG16), and Microtubule-associated protein light chains 3-2 (LC3-II), and by reducing the expression levels of Mechanistic target of rapamycin kinase (mTOR) and Microtubule-associated protein light chains 3-1 (LC3-I). Cell apoptosis was induced by increasing the expression of apoptosis markers Bcl-2 associated X protein (Bax), Cysteinyl aspartate specific proteinase 9 (Caspase9), cleaved Caspase9, Cysteinyl aspartate specific proteinase 3 (Caspase3), and cleaved Caspase3, and by reducing the expression of B cell lymphoma/leukemia 2 (Bcl-2). At the same time, Cd decreased the expression of phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt), and their phosphorylation. We treated IPEC-J2 cells with the PI3K activator 740Y-P and analyzed the morphological changes as well as autophagy and apoptosis-related gene expression. The results showed that 740Y-P could reduce apoptosis and autophagy induced by Cd. In conclusion, our findings suggest that Cd induces intestinal apoptosis and autophagy in swine by inactivating the PI3K/Akt signaling pathway.

Ficus natalensis extract alleviates Cadmium chloride-induced testicular disruptions in albino rats

BACKGROUND

Cadmium is a potential environmental pollutant with worldwide health problems. Many Ficus species are reported to have an extensive diversity of traditional uses, among them the treatment of reproductive toxicity.

OBJECTIVES

This study set out to evaluate the effect of Ficus natalensis extract on the testicular impairments induced by cadmium chloride (CdCl₂) and investigated the potential mechanisms associated with its treatment.

METHODS

Thus, 40 male albino rats were categorized into 4 groups (n = 10); group I (control), group II (cadmium-treated group) orally received 5 mg/kg/day CdCl₂ for one month, group III (cadmium + Ficus natalensis extract) orally received 5 mg/kg/day CdCl₂ for one month plus 200 mg/kg/day Ficus natalensis extract for another month, and group IV (cadmium + reference drug (mesterolone) orally received 5 mg/kg/day CdCl₂ for one month plus 4.16 mg/kg/day mesterolone for another month.

RESULTS

At the end of experiment, CdCl₂ administration markedly induced histological and histo-morphometric changes with a substantial (p < 0.05) decrease in the sperm count, sperm motility, serum TAC, serum testosterone, downregulation in the mRNA expression levels of testicular 17β-HSD and StAR, in addition to a significant increase in serum TNF-α and testicular MDA level compared to the control group. Conversely, the treatment with Ficus natalensis methanolic extract as well as the reference drug significantly ameliorated the above-mentioned adverse effects induced by CdCl₂.

CONCLUSIONS

Our results suggested that Ficus natalensis extract can attenuate the CdCl₂-induced testicular impairments via inhibiting the oxidative cell damage and inflammation that contributed to CdCl₂ toxicity.

The Association Between Dairy Product Consumption and Asthenozoospermia Risk: A Hospital-Based Case-Control Study

Background: Evidence of an association between dairy product and main related dairy nutrient intake, and the asthenozoospermia risk have been limited and controversial. Methods: A hospital-based case-control study including 549 men with asthenozoospermia and 581 normozoospermic controls was carried out in the infertility clinics of Shengjing Hospital of China Medical University between June, 2020 and December, 2020. Dietary intake was assessed with a validated food frequency questionnaire. According to the World Health Organization guidelines, semen parameters were collected through masturbation and were measured with WLJY9000 instrument and flow cytometry. The daily intake of dairy products and related nutrients was categorized into three groups according to control distribution, and the lowest tertile was used as the reference category. An unconditional multiple logistic regression was used to estimate the odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) for asthenozoospermia risk. Results: After adjustment for potential confounders, we found no statistically significant associations between the intake of total dairy products and asthenozoospermia risk (OR_T3vs.T1 = 1.19, 95%CI = 0.85-1.67). Additionally, we generated null findings regarding the main related nutrients from dairy, including protein (OR_T3vs.T1 = 1.19, 95%CI = 0.85-1.68), fat (OR_T3vs.T1 = 1.28, 95%CI = 0.91-1.80), calcium (OR_T3vs.T1 = 1.20, 95%CI = 0.85-1.68), saturated fatty acids (OR_T3vs.T1 = 1.30, 95%CI = 0.92-1.83), and phosphorous (OR_T3vs.T1 = 1.18, 95%CI = 0.84-1.67), and the asthenozoospermia risk. Of note, after stratification by body mass index (BMI), and the saturated fatty acids consumption from dairy was significantly associated with a higher asthenozoospermia risk (OR_T3vs.T1 = 1.76, 95%CI = 1.01-3.09) among participants with a BMI below 25 kg/m². Conclusion: This study provided limited evidence of an association between the intake of total dairy products and the main related dairy nutrients including protein, fat, calcium, saturated fatty acids, and phosphorus, and the asthenozoospermia risk. Further studies are warranted to confirm our findings in the future.

Ultra-acute exposure to cadmium does not impair whitefish sperm motility

Cadmium (Cd) exposure can impair the traits of aquatic animals associated with reproduction. In natural lakes Cd is typically detected at concentrations below 0.001 mg l^-1 . The authors investigated the impact of ultra-acute Cd exposure on sperm motility in European whitefish (Coregonus lavaretus). They activated sperm with water containing various nominal concentrations of Cd and recorded sperm motility parameters. Only the highest Cd concentration (500 mg l^-1 ) was associated with decreased sperm swimming velocity and increases in both the percentage of static cells and curvature of the sperm swimming trajectory. The results indicate that environmentally realistic concentrations of Cd during the sperm motility activation are not critically harmful to male C. lavaretus fertilization potential.

Beneficial effects and health benefits of Astaxanthin molecules on animal production: A review

Astaxanthin (AST) is a red pigment of carotenoid and is considered a high-quality keto-carotenoid pigment with food, livestock, cosmetic, therapeutic and nutraceutical proposes. Astaxanthin exists naturally in fish, crustacean, algae, and birds that naturally exists, principally as fatty acid esters. Many investigations have exhibited the beneficial impacts of astaxanthin when utilized as a pharmaceutical agent in animal nutrition. Astaxanthin has a variety of considerable biological actions, such as being antihypertensive, an antioxidant, anti-obesity properties, and anti-carcinogenic. Astaxanthin has recently acquired popularity as a powerful immunomodulator to maintain the health status and well-being of both animals and humans. The use of astaxanthin is broadly utilized in medical sciences and the nutrition pf aquatic species; however, it presently has limited applications in broader animal nutrition. Understanding astaxanthin's structure, source, and mode of action in the body provides a conceptual base for its clinical application and could enhance the screening of compounds associated with the treatment of many diseases. This review article aims to clarify the important aspects of astaxanthin such as its synthesis, bioavailability, and therapeutics actions, with special interest in practical applications. Awareness of this benefits and production is expected to aid the livestock industry to develop nutritional strategies that ensure the protection of animal health.

The effect of seminal plasma cadmium and lead levels on semen parameters in male subjects of infertile couples: a prospective cohort study

The aim of this prospective study was to investigate whether there is a relationship between seminal plasma cadmium (Cd) and lead (Pb) levels and semen parameters in male partners of infertile couples. Two hundred fifty one (251) men recruited with no history of occupational exposure to toxic metals. After semen analysis, seminal Cd and Pb levels were measured using atomic absorption spectrometry. Cadmium levels in men with hypospermia was significantly higher than men with normal semen volume (p = .049). In contrast, there was no statistically significant difference in median seminal Pb levels between men with hypospermia and men with normal semen volume (p = .13). There was no statistically significant association between seminal plasma Cd and Pb levels sperm concentration, motility, morphology and total progressively motile sperm count. These findings suggest that environmental Cd exposure may contribute to low semen volume in male partners of infertile couples.IMPACT STATEMENTWhat is already known on this subject? Toxic metals may adversely affect both male and female reproductive system.What the results of this study add? Seminal plasma cadmium levels in men with hypospermia were statistically significantly higher than men with normal semen volume.What the implications are of these findings for clinical practice and/or further research? Patients should be informed about possible adverse effects of toxic metals.

Yishentongluo decoction in treatment of idiopathic asthenozoospermia infertility: Study protocol for a randomized controlled trial

BACKGROUND

The reproductive dilemma faced by men has always been the focus of the whole society. Idiopathic asthenozoospermia (AZS), as one of the common causes of male infertility, lack of specific treatment. Traditional Chinese medicine has shown potential benefits in the management of male infertility. Yishentongluo decoction (YSTL) is a representative Chinese herbal formula; however, there is still no rigorous clinical trial supporting its application. Therefore, we designed a randomized controlled trial to evaluate the efficacy and safety of YSTL for patients with idiopathic AZS and explain the possible action mechanisms of YSTL in improving sperm motility.

METHODS

In this randomized controlled study, a total of 160 eligible patients will be assigned to YSTL group or the Levocarnitine oral solution group in a 1:1 ratio. The treatment period will be 12 weeks and the follow-up period will last 4 weeks. The primary outcome will be the the progressive (motility), sperm rate (%). Secondary outcomes will include the progressive (motility) + non-progressive (motility) sperm rate(%), total effective sperm count, inner mitochondrial membrane potential (MMP) in spermatozoa, and spouse pregnancy rate (%). Safety outcomes will cover electrocardiogram , blood tests (including blood routine test, hepatic function, and renal function), urine routine test, and stool routine test. The semen parameters, sperm MMP test, and all the safety outcomes will be performed at the baseline, 4th, 8th and 12th week. The pregnancy outcome will be evaluated at 4 weeks after treatment.

DISCUSSION

This study will provide initial evidence regarding the efficacy and safety of YSTL in the treatment of idiopathic AZS with kidney deficiency and blood stasis pattern. In addition, potential mechanisms of YSTL in improving sperm motility will be explored based on sperm MMP test.

TRIAL REGISTRATION

Chinese Clinical Trials Register identifier, ChiCTR2000033290, registered on 26 May 2020.

Current mechanistic perspectives on male reproductive toxicity induced by heavy metals

Environmental and occupational exposures to heavy metals have led to various deleterious damages to the biological system of which infertility is one of them. Infertility is a global public health concern, affecting 15% of all couples of reproductive age. Out of the 100% cases of reported infertility among couples, 40% of the cases are related to male factors; including decreased semen quality. This review focuses on the recent mechanistic perspectives of heavy metal-induced male reproductive toxicity. The associated toxic metal-mediated mechanisms of male reproductive toxicity include ion mimicry, disruption of cell signaling pathways, oxidative stress, altered gene expression, epigenetic regulation of gene expression, apoptosis, disruption of testis/blood barrier, inflammation and endocrine disruption. The current literature suggests that non-coding RNAs (ncRNAs) mediate paternal intergenerational epigenetic inheritance and thus has a direct functional importance, as well as possess novel biomarker potential, for male reproductive toxicity. To identify the specific ncRNAs with the most profound impacts on heavy metal-induced male reproductive toxicity should be thrust of further research.

Determination of cadmium induced acute and chronic reproductive toxicity with Raman spectroscopy

Cadmium (Cd) is one of the toxic heavy metals which is confirmed to be related to male sterile. Here, confocal Raman spectroscopy was employed to detect biomolecular composition and changes in testis under acute and chronic Cd treatment. Specific Raman shifts associated with mitochondria, nucleic acids, proteins, lipids, and cholesterol were identified which were distinguishing among groups undergoing different Cd treatment times. Supporting evidences were provided by conventional experimental detections. The relevant biochemical parameters, pathological changes, and protein expression related to testosterone synthesis were all changed and consistent with Raman spectrum information. In conclusion, confocal Raman spectroscopy presents a reliable data and provides a novel method which is expected to be a promising strategy in reproduction toxicity research.

Effect of astaxanthin nanoparticles in protecting the post-thawing quality of rooster sperm challenged by cadmium administration

The protective role of astaxanthin nanoparticles (Ast NPs, 25 mg/kg p.o) against cadmium (Cd, 1 mg/100 g b.w. SC), a known inductor of lipid peroxidation and changes in the antioxidant defense system in the Ross 308 breeder roosters sperm, was examined. Sperm motility (computer-assisted sperm motility analysis), membrane integrity (hypoosmotic swelling test), viability, total abnormality, and enzymatic parameters were assessed after thawing. The testis/body weight (mg/kg) ratio and HE staining results of testis were also performed. The obtained results showed that Cd induced detrimental effects on testis and sperm, while Cd treated by Ast NPs (Cd Ast) diminished this change compared to the Cd group. Cd-treated group resulted in significantly (P < 0.05) lowest total (37.29 ± 2.46) and progressive (5.84 ± 0.47) motility and decreased antioxidant enzyme activity (CAT, TAC, and GPx), as well as producing a significant (P < 0.05) decrease in testis weight (mg) compared to the control group. Treatment with Ast NPs (Ast NPs + Cd) had reversed Cd-induced changes in the antioxidant defense system and significantly prevented Cd-induced testis damage. In conclusion, the results of our work suggest that Ast NPs at 25 mg/kg act as a potent antioxidant in protecting rooster testes against oxidative stress induced by Cd.

In vitro and in vivo effects of a mycotoxin, deoxynivalenol, and a trace metal, cadmium, alone or in a mixture on the intestinal barrier

Deoxynivalenol (DON), one of the most widespread mycotoxins in Europe, and cadmium (Cd), a widespread environmental pollutant, are common food contaminants. They exert adverse effects on different organs including kidney, liver, and intestine. The intestine is a common target of DON and Cd when they are ingested. Most studies have focused on their individual effects whereas their combined toxicity has rarely been studied. The aim of this study was thus to evaluate their individual and combined effects on the intestinal barrier function in vitro and in vivo. In vitro, Caco-2 cells were treated with increasing concentrations of DON and Cd (1-30 μM). In vivo, Wistar rats were used as controls or exposed to DON contaminated feed (8.2 mg/kg feed), Cd-contaminated water (5 mg/l) or both for four weeks. In Caco-2 cells, DON, Cd and the DON+Cd mixture reduced transepithelial electrical resistance (TEER) and increased paracellular permeability in a dose-dependent manner. Impairment of the barrier function was associated with a decrease in the amount of E-cadherin and occludin after exposure to the two contaminants alone or combined. A decrease in E-cadherin expression was observed in rats exposed to the two contaminants alone or combined, whereas occludin expression only decreased in animals exposed to DON and DON+Cd. Jejunal crypt depth was reduced in rats exposed to DON or Cd, whereas villi height was not affected. In vitro and in vivo results showed that the effects of exposure to combined DON and Cd on the intestinal barrier function in the jejunum of Wistar rats and in the colorectal cancer cell line (Caco-2) was similar to the effects of each individual contaminant. This suggests that regulations for each individual contaminant are sufficiently protective for consumers.

Health risk assessment of cadmium, chromium and nickel from car paint dust from used automobiles at auto-panel workshops in Nigeria

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Fairly used vehicular importation into Nigeria is reputed to be the highest in Africa.

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Most modern cars/vehicles are fitted with some electronic, electrical devices and mechanical components that contain heavy metals.

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Due to prevailing economic hardship and the fact that new vehicles are out of reach of average Nigerians, the vehicles are taken to the automobile workshops for total overhaul and refurbishing.

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Metal values of soil from all the workshops were higher than that of paint dust matrix, this can be attributed to the fact that as vehicles are repaired and taken away, more are brought into the workshops for repair.

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For cadmium and chromium, children are marginally at risk of cancer than adult through ingestion, while dermal contact does not pose any serious threat.

Nigeria’s economic problems which inhibited local production has resulted in massive importation of used automobiles. Most of these automobiles need some repairs and reworking, having outlived their lifespan in the manufacturer’s country. This study centers on the human carcinogenic and non-carcinogenic health risk assessment of cadmium, chromium and nickel exposures from reworking of imported used vehicles. Scraped car paint dusts from 56 Japanese made cars were collected from 8 different panel beating (body works) workshops (A–H) in Southeastern Nigeria. They were homogenized, mixed, divided into fine particles, filtered and digested by standard method. The filtrates were assayed for cadmium, chromium and nickel with atomic absorption spectrophotometry (AAS, 200A), workshops F and D have the highest concentration (mg/kg) of Cd (3.58 ± 0.02) and (3.36 ± 0.04) and higher than levels in workshops A, B, C, E, G and H. Chromium (mg/kg) in workshops F and G were (2.87 ± 0.04) and (2.95 ± 0.06) and higher than the other workshops. Nickel in workshop A (3.84 ± 0.04) is close to other workshop values. The highest hazard quotients for adults were cadmium in workshops B (1.37E-01), D (1.69E-01), E (1.79E-01) (inhalation), chromium [workshops G (5.45E-02), F (5.29E-02) and C (5.24E-02) inhalation]. Nickel -workshop A (5.9E-03) for children (inhalation). HQ in children through ingestion is cadmium (3.72E-04) workshop F and ingestion- 3.21E-01(workshop F) while nickel is 1.06E-02 (workshop A).The highest cancer risks were in exponents -4,-7 and -8 (adult) and -3, -6 and -9 (children) for workshops A–H through inhalation, ingestion and dermal contact, exposures to scrap car paint dust may be of significant public health importance in Nigeria as it can add to body burden of some carcinogenic heavy metals.

Toxin-induced hormesis may restrain aging

Mild environmental stress might have beneficial effects in aging by activating maintenance and repair processes in cells and organs. These beneficial stress effects fit to the concept of hormesis. Prominent stressors acting in a hormetic way are physical exercises, fasting, cold and heat. This review will introduce some toxins, which have been found to induce hormetic responses in animal models of aging research. To highlight the molecular signature of these hormetic effects we will depict signaling pathways affected by low doses of toxins on cellular and organismic level. As prominent examples for signaling pathways involved in both aging processes as well as toxin responses, PI3K/Akt/mTOR- and AMPK-signal transduction will be described in more detail. Due to the striking overlap of signaling pathways mediating toxin induced responses and aging processes we propose considering the ability of low doses of toxins to slow down the rate of aging.

Countering the effects of lead as an environmental toxicant on the microanatomy of female reproductive system of adult wistar rats using aqueous extract of Ficus vogelii

BACKGROUND

Lead without nutritional value is a widely studied occupational and environmental toxicant. Leads' toxic effects on female reproduction are decreased fertility, inability to sustain pregnancy and reduced pregnancy.

OBJECTIVE

This study aimed at examining the effect of oral administration of lead acetate (1.5 mg/kg) on the histology of female albino Wistar rats' ovary and Uterus and the extracts' protective role against toxicity.

METHODS

The experiment took 28 days involving 25 female Wistar rats divided into 5 groups A, B, C, D and E. A is an untreated group that received normal saline, D lead acetate group that received lead acetate solution, E received aqueous extract, B and C low and high dose of aqueous extract respectively and lead acetate solution.

RESULTS

The positive control group showed a significant increase in SOD at P ≤ 0.01 compared to the negative control. Group E showed significant decrease ovarian SOD. The organs weights were significantly reduced in group D. The changes seen in the organs include oedema, necrosis, optical empty spaces, denudations and fatty changes. Administrating the extract protected the organs against the lead acetate. These alterations are shown to cause infertility in female rats.

CONCLUSION

The results suggested that the extract has protective role against lead reproductive toxicity.

Protective effects of methanol extract of Plukenetia conophora seeds and 4H-Pyran-4-One 2,3-Dihydro-3,5-Dihydroxy-6-Methyl on the reproductive function of male Wistar rats treated with cadmium chloride

OBJECTIVES

Male infertility caused by exposure to heavy metals is a current global issue. Exposure to cadmium chloride (CdCl2) negatively affects the male reproductive system. Many infertile people, especially in developing countries, resort to folkloric treatment. Plukenetia conophora is used in Nigerian folk medicine to promote fertility. This study investigated the effects of Plukenetia conophora (PC) and 4H-Pyran-4-One 2,3-Dihydro-3,5-Dihydroxy-6-Methyl (DDMP) on Wistar rats with cadmium chloride-induced testicular damage.

METHODS

Forty-two male Wistar rats (150-190g) were divided into seven groups (n=6) and treated daily for 54 days as follows: Controls (normal saline); CdCl2 (2mg/kg single IP dose); CdCl2 + 200 mg/kg vitamin E; CdCl2 + 100 or 200 mg/kg PC; and CdCl2 + 25 or 50 mg/kg DDMP. The rats were sacrificed 55 days after the start of the study; Samples were collected for analysis. Biochemical parameters malondialdehyde, nitric oxide, antioxidant enzymes, and proton pumps were measured by spectrophotometry. Reproductive hormones were measured using ELISA. Data were analysed using ANOVA and differences in mean values were considered significant at p<0.05.

RESULTS

Significant increases in sperm count, motility, and viability were observed in the groups given CdCl2+Vitamin E, CdCl2+PC or CdCl2+DDMP as compared with the CdCl2 group. Malondialdehyde and nitric oxide levels in the groups treated with CdCl2+PC or CdCl2+DDMP decreased significantly when compared with the group given CdCl2. Significant increases were observed in antioxidant enzymes, proton pump, and testosterone in the groups treated with CdCl2+PC or CdCl2+DDMP, respectively.

CONCLUSION

Plukenetia conophora alleviated male reproductive toxicity induced by cadmium chloride in Wistar rats. 4H-Pyran-4-One 2,3-Dihydro-3,5-Dihydroxy-6-Methyl present in Plukenetia conophora may be responsible for the ameliorative effects.

Quantitative assessment of heavy metal effects on sperm function using computer-aided sperm analysis and cytotoxicity assays

One known environmental risk factor impacting on human reproduction is heavy metal pollution. Although some metals (e.g., Cu, Se and Zn) have protective effects on the male reproductive system in low doses, heavy metals can accumulate to toxic levels and result in poor semen quality and decreased sperm function. We investigated the effect of CuSO₄ and CdCl₂ (10, 50, 100 and 250 µg/ml or 500 µg/ml) on human sperm motility and vitality by using computer-aided sperm analysis (CASA) and two cytotoxicity assays (WST-1 and XTT). Several sperm motility parameters were significantly reduced after 5 hr of exposure to the highest concentrations of CuSO₄ (250 µg/ml) and CdCl₂ (500 µg/ml). The WST-1 assay also revealed significantly lower absorbance values for 50, 100 and 250 µg/ml CuSO₄ and for 500 µg/ml CdCl₂ ; however, no significant effect was seen with XTT. The calculated average IC₅₀ value was 50.31±  4.34 µg/ml for CuSO₄ and 392.32  ±76.79 µg/ml for CdCl₂ . The effects of these metals were confirmed with MgCl₂ , a positive control. This study provides threshold concentrations for the harmful effect of CuSO₄ and CdCl₂ on human spermatozoa and recommends the use of WST-1 as vitality assay in future in vitro studies.

Downregulation of DJ-1 Fails to Protect Mitochondrial Complex I Subunit NDUFS3 in the Testes and Contributes to the Asthenozoospermia

Asthenozoospermia (AS), an important cause of male infertility, is characterized by reduced sperm motility. Among the aetiologies of AS, inflammation seems to be the main cause. DJ-1, a conserved protein product of the PARK7 gene, is associated with male infertility and plays a role in oxidative stress and inflammation. Although our previous studies showed that a reduction in DJ-1 was accompanied by mitochondrial dysfunction in the sperm of patients with AS, the specific mechanism underlying this association remained unclear. In this study, we found that compared to the patients without AS, the expression of mitochondrial protein nicotinamide adenine dinucleotide dehydrogenase (ubiquinone) Fe-S protein 3 (NDUFS3) was also significantly decreased in the sperm of patients with AS. Similarly, decreased expression of DJ-1 and NDUFS3 and reduced mitochondria complex I activity were evident in a rat model of AS. Moreover, we showed that the interaction between DJ-1 and NDUFS3 in rat testes was weakened by ORN treatment. These results suggest that the impaired mitochondrial activity could be due to the broken interaction between DJ-1 and NDUFS3 and that downregulation of DJ-1 in sperm and testes contributes to AS pathogenesis.

Dose-Dependent Differential Effects of In Vivo Exposure of Cadmium on Myometrial Activity in Rats: Involvement of VDCC and Ca2+-Mimicking Pathways

Present study was undertaken to study the effect of 28-days exposure of female adult rats to cadmium (Cd) in drinking water @ 3, 10 and 30 parts per million (ppm) on myometrial responsiveness to different spasmogens and unravel the possible mechanism of alterations in myometrial activity. Cadmium and Ca²⁺ levels in blood and uterus were measured by atomic absorption spectroscopy while isometric tension in myometrial strips was measured using data acquisition system-based physiograph. Dose-dependent increase in levels of cadmium was observed in both blood and uterus while calcium was increased only in the uterus as compared to those in control. Significant increase in absolute tension and mean integral tension along with non-significant increase in frequency of myometrial contraction was observed in rats of Cd-treated groups. As compared to the control, cadmium decreased and increased the effects of calcium chloride, 80 mM KCl, histamine (0.1 μM) and oxytocin (10^-2 IU/ml) in lower-dose (3 ppm) and higher-dose groups (10 and 30 ppm), respectively. Cadmium potentiated and inhibited the relaxant response to phenylephrine in myometrium of rats at lower-dose (3 ppm) and highest-dose (30 ppm) Cd-treated groups, respectively. Results of our study revealed that Cd accumulates in the myometrium of rats and alters its responsiveness to oxytocin, histamine, 80 mM KCl, calcium chloride and phenylephrine, and these effects are differentially mediated depending on levels of exposure possibly through voltage-dependent calcium channel (VDCC) and Ca²⁺-mimicking pathways.

Reproductive effects of cadmium on sperm function and early embryonic development in vitro

Cadmium is a major environmental toxicant that is released into the atmosphere, water and soil in the form of cadmium oxide, cadmium chloride, or cadmium sulfide via industrial activities, such as the manufacturing of batteries and pigments, metal smelting and refining and municipal waste incineration. In the present study, we investigated the effects of cadmium exposure on sperm quality parameters, fertilization capacity and early embryonic development. Our study showed that in vitro incubation of human or mouse sperms with cadmium for a long time (up to 24 hours) could significantly decreased sperm motility in a concentration- and time-dependent manner. Exposure to cadmium in the environment for a short term (30 min) did not affect sperm motility but significantly reduced in vitro fertilization rate. We also evaluated the effects of cadmium at concentrations of 0.625 μg/ml, and 1.25 μg/ml on early embryonic development in vitro and observed that the blastocyst formation rate dramatically decreased with increasing cadmium concentration. This finding emphasizes the hazardous effects of cadmium on sperm quality as well as on natural embryo development and raises greater concerns regarding cadmium pollution.

The environment and male reproduction: The effect of cadmium exposure on reproductive function and its implication in fertility

Cadmium is an environmental pollutant known as endocrine disruptor. Testis is particularly susceptible to cadmium, and testis injury occurs at high but even low levels of exposure. Cadmium reproductive toxicity is mediated by multiple mechanisms, including structural damage to testis vasculature and blood-testis barrier, inflammation, cytotoxicity on Sertoli and Leydig cells, oxidative stress mainly by means of mimicry and interference with essential ions, apoptosis, interference with selected signaling pathways and epigenetic regulation of genes involved in the regulation of reproductive function, and disturbance of the hypothalamus-pituitary-gonadal axis. The current review outlines epidemiological observational findings from environmental and occupational exposure in humans, and reports experimental studies in humans and animals. Lastly, a focus on the pathogenetic mechanisms of cadmium toxicity and on the specific mechanisms of cadmium sensitivity and resistance, particularly assessed in animal models, is included. Despite convincing experimental findings in animals and supporting evidences in humans identifying cadmium as reproductive toxicant, observational findings are controversial, suffering from heterogeneity of study design and pattern of exposure, and from co-exposure to multiple pollutants.

Increasing CACNA1C expression in placenta containing high Cd level: an implication of Cd toxicity

Cadmium (Cd) has known to produce many adverse effects on organs including placenta. Many essential transporters are involved in Cd transport pathways such as DMT-1, ZIP as well as L-VDCC. Fourteen pregnant women participated and were divided into two groups: high and low Cd-exposed (H-Cd, L-Cd) groups on the basis of their residential areas, Cd concentrations in the blood (B-Cd), urine (U-Cd), and placenta (P-Cd). The results showed that the B-Cd and U-Cd were significantly increased in H-Cd group (p < 0.05). Interestingly, the P-Cd in H-Cd group was elevated (p < 0.05) and positively related to their B-Cd and U-Cd values (p < 0.05). However, the mean cord blood Cd (C-Cd) concentration in H-Cd group was not significantly increased about 2.5-fold when comparing to L-Cd group. To determine the Cd accumulation in placental tissues, metallothionein-1A (MT-1A) and metallothionein-2A (MT-2A) expressions were used as biomarkers. The results revealed that mean MT-1A and MT-2A mRNAs and MT-1/2 proteins were up-regulated in H-Cd group (p < 0.05). In addition, the Ca channel alpha 1C (CACNA1C) mRNA and protein expressions were noticeably elevated in H-Cd group (p < 0.05). From these findings, we suggested that CACNA1C might be implicated in Cd transport in human placenta.

Cadmium inhibits mouse sperm motility through inducing tyrosine phosphorylation in a specific subset of proteins

Cadmium (Cd) has been reported to impair male fertility, primarily by disrupting sperm motility, but the underlying molecular mechanism remains unclear. Here we investigated the effects of Cd on sperm motility, tyrosine phosphorylation, AMP-activated protein kinase (AMPK) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity, and ATP levels in vitro. Our results demonstrated that Cd inhibited sperm motility, GAPDH activity, AMPK activity and ATP production, and induced tyrosine phosphorylation of 55-57KDa proteins. Importantly, all the parameters affected by Cd were restored to normal levels when incubated with 10μM Cd in the presence of 30μM ethylene diamine tetraacetic acid (EDTA). Interestingly, changes of tyrosine phosphorylation levels of 55-57KDa proteins are completely contrary to that of other parameters. These results suggest that Cd-induced tyrosine phosphorylation of 55-57KDa proteins might act as an engine to block intracellular energy metabolism and thus decrease sperm motility.

Environmentally Realistic Doses of Cadmium as a Possible Etiologic Agent for Idiopathic Pathologies

Cadmium is a heavy metal of increasing environmental concern that has long been associated to several human pathological processes. Recent population surveys have correlated cadmium non-occupational exposure to widespread idiopathic pathologies. Food and tobacco are reported to be the main exposure sources of cadmium to the general population, as phosphate fertilizers are rich in such a metal, thus contaminating the crops. Although its mechanisms of toxicity are not a consensus in the literature, it is well established that reactive oxygen species play a key role in this process, leading to the oxidation of several biological molecules. We have therefore assessed whether three environmentally realistic doses of cadmium alter the oxidative status of Wistar rat testis and eventually result in histological damages. Our results show that even the lowest environmental dose of cadmium was able to disturb the endogenous antioxidant system in Wistar testis, although an increase in lipid peroxidation was observed only within the group exposed to the highest environmental dose. Despite that no remarkable morphological changes were observed in any group, significant alterations in blood vessel lumen were reported for some cadmium-exposed animals, suggesting that endothelium is one of the primary targets involved in cadmium toxicity.

Association between environmental exposure to cadmium and human semen quality

Cadmium (Cd) is a heavy metal with toxicant to reproductive functions. The aim of this study was to explore the effects of environmental exposure to Cd on human semen quality. A total of 587 men from the general population, aged from 20 to 59 years old, and without occupational exposure to Cd were recruited from three provinces in China to participate in the study. The median of serum Cd was 1.9 μg/L (P25-P75:1.1-2.9). In case Cd was less than or equal to 6.3 μg/L (P95) and the semen parameters were logarithmically transformed, the inverse associations between Cd and semen volume (-0.03 ± 0.007), progressive motility (-0.01 ± 0.004), and sperm morphology (-0.04 ± 0.004) were found across the whole group, after adjusting for age group, occupation, season of semen sample collection, abstinence intervals, smoking, alcohol drinking, and body mass index. Our findings indicate that higher Cd may reduce the semen volume, progressive motility, and morphology among men without occupational exposure to Cd.

Sexually immature male ERE-Luc reporter mice to assess low dose estrogen-like effects of CdCl2 versus dietary Cd

CdCl2 salt is widely used in exposure oriented studies, while the biological exposure of Cadmium (Cd) occurs mostly through diet. Hence, we designed a in vivo imaging methodology with sexually immature male ERE-Luc reporter mice to test the estrogen-like (EL) effects of Cd as a natural component in wheat and flax bread based diets (containing 17.57 and 49.22 ug/kg Cd concentrations respectively) and CdCl2 per-oral dose of 1 ug/kg/bw/day. Total exposure of ingested and % bioaccumulation of Cd in selected organs were estimated as 547 ng (4.4%), 776 ng (0.3%) and 2131.8 ng (0.1%) corresponding to CdCl2, wheat and flax bread based diet treatments respectively. Cd from CdCl2 bioaccumulated more readily, despite the exposure of Cd is higher with bread based diets. Longitudinal in vivo imaging did not reveal significant changes in luciferase activity. White adipose tissue (WAT) and prostate were identified as novel target organs of Cd. Indeed, the rest of the observed EL effects, endogenous target gene expression and necropsy findings are not consistent to any particular organ or treatment. This implies that, the observed EL effects due to low doses of Cd (either from CdCl2 or dietary form) occur only as subtle changes at the molecular level, but inadequate to cause significant changes at the anatomo-pathological level during the 21 day exposure period. The study demonstrates the sensitivity of the methodology to assess EL effects of food embedded Cd and underlines the limitations of directly extrapolating the results of suspected chemicals in their pure form to dietary exposure scenarios.

Resveratrol reverses cadmium chloride-induced testicular damage and subfertility by downregulating p53 and Bax and upregulating gonadotropins and Bcl-2 gene expression

This study was performed to investigate the protective and therapeutic effects of resveratrol (RES) against CdCl2-induced toxicity in rat testes. Seven experimental groups of adult male rats were formulated as follows: A) controls+NS, B) control+vehicle (saline solution of hydroxypropyl cyclodextrin), C) RES treated, D) CdCl2+NS, E) CdCl2+vehicle, F) RES followed by CdCl2 and M) CdCl2 followed by RES. At the end of the protocol, serum levels of FSH, LH and testosterone were measured in all groups, and testicular levels of TBARS and superoxide dismutase (SOD) activity were measured. Epididymal semen analysis was performed, and testicular expression of Bcl-2, p53 and Bax was assessed by RT-PCR. Also, histopathological changes of the testes were examined microscopically. Administration of RES before or after cadmium chloride in rats improved semen parameters including count, motility, daily sperm production and morphology, increased serum concentrations of gonadotropins and testosterone, decreased testicular lipid peroxidation and increased SOD activity. RES not only attenuated cadmium chloride-induced testicular histopathology but was also able to protect against the onset of cadmium chloride testicular toxicity. Cadmium chloride downregulated the anti-apoptotic gene Bcl2 and upregulated the expression of pro-apoptotic genes p53 and Bax. Resveratrol protected against and partially reversed cadmium chloride testicular toxicity via upregulation of Bcl2 and downregulation of p53 and Bax gene expression. The antioxidant activity of RES protects against cadmium chloride testicular toxicity and partially reverses its effect via upregulation of BCl2 and downregulation of p53 and Bax expression.

Exposure to cadmium in male urban and rural workers and effects on FSH, LH and testosterone

OBJECTIVE

This cross-sectional study was conducted to assess the relationship between exposure to cadmium and circulating reproductive hormone levels in urban and rural male workers.

MATERIALS AND METHODS

Urinary cadmium, blood cadmium, luteinizing hormone (LH), follicle stimulating hormone (FSH) and testosterone were obtained from 86 non-smoking traffic policemen and 86 subjects working as roadmen in a rural area. All subjects were monitored to evaluate airborne exposure to cadmium.

RESULTS

The mean value of exposure to cadmium was 1.3 ng m(-3) in traffic policemen, while the mean value was less than 0.5 ng m(-3) in roadmen. The mean concentrations of urinary cadmium (1.4 vs. 0.9 μg g(-1) creatinine; p=0.001), blood cadmium (1.1 vs. 0.7 μg l(-1); p=0.000), FSH (2.6 vs. 3.2 μlU ml(-1); p=0.02) and LH (2.6 vs. 3.1 μlU ml(-1); p=0.03) were significantly different between traffic policemen and roadmen. No differences were found in the mean values of testosterone between the two groups. Multiple linear regression models showed associations between (a) urinary cadmium, airborne cadmium, working life, job category and consumption of water from water supply (b) blood cadmium, airborne cadmium and job category (c) the values of FSH and age, working life, job category, urinary cadmium and blood cadmium (d) the values of LH and both the age and working life.

CONCLUSION

The above results must be confirmed by further studies, but they indicate the influence of exposure to the cadmium present in urban air on the circulating FSH, even at low doses.

Insight into oxidative stress in varicocele-associated male infertility: part 1

Varicocele is recognized as the leading cause of male infertility because it can impair spermatogenesis through several distinct pathophysiological mechanisms. Current evidence supports oxidative stress as a key element in the pathophysiology of varicocele-related infertility, although these mechanisms have not yet been fully described. Measurement of the reactive oxygen species and other markers of oxidative stress, including the levels of the antioxidant enzymes catalase and superoxide dismutase, can provide valuable information on the extent of oxidative stress and might guide therapeutic management strategies. The testis can respond to varicocele-associated cell stressors, such as heat stress, ischaemia or production of vasodilators (for example, nitric oxide) at the expense of the generation of excessive reactive oxygen species. These responses have their own implications in exacerbating the underlying oxidative stress and on the subsequent infertility.

Sperm quality in adult male rats exposed to cadmium in utero and lactation

Recent studies indicate that several anomalies of the male reproductive system may be produced by acute or chronic exposure to chemical substances released into the environment, attributed to increased industrial development. Among these substances are trace metals such as cadmium (Cd). The aim of this study was to assess reproductive parameters in adult male rats whose mothers were exposed to Cd during pregnancy and lactation. For this, pregnant rats were divided into two experimental groups: treated rats, which received ad libitum cadmium acetate (CdAc) solution in distilled water (10 mg Cd/L), and control rats, which received sodium acetate (NaAc) solution in distilled water (equimolar to the CdAc). The results showed that the exposure to Cd in utero and through lactation adversely affected sperm quality of adult rats, as evidenced by compromised sperm morphology and motility and increased rate of cell death in testis.

The blood-testis barrier and its implications for male contraception

The blood-testis barrier (BTB) is one of the tightest blood-tissue barriers in the mammalian body. It divides the seminiferous epithelium into the basal and the apical (adluminal) compartments. Meiosis I and II, spermiogenesis, and spermiation all take place in a specialized microenvironment behind the BTB in the apical compartment, but spermatogonial renewal and differentiation and cell cycle progression up to the preleptotene spermatocyte stage take place outside of the BTB in the basal compartment of the epithelium. However, the BTB is not a static ultrastructure. Instead, it undergoes extensive restructuring during the seminiferous epithelial cycle of spermatogenesis at stage VIII to allow the transit of preleptotene spermatocytes at the BTB. Yet the immunological barrier conferred by the BTB cannot be compromised, even transiently, during the epithelial cycle to avoid the production of antibodies against meiotic and postmeiotic germ cells. Studies have demonstrated that some unlikely partners, namely adhesion protein complexes (e.g., occludin-ZO-1, N-cadherin-β-catenin, claudin-5-ZO-1), steroids (e.g., testosterone, estradiol-17β), nonreceptor protein kinases (e.g., focal adhesion kinase, c-Src, c-Yes), polarity proteins (e.g., PAR6, Cdc42, 14-3-3), endocytic vesicle proteins (e.g., clathrin, caveolin, dynamin 2), and actin regulatory proteins (e.g., Eps8, Arp2/3 complex), are working together, apparently under the overall influence of cytokines (e.g., transforming growth factor-β3, tumor necrosis factor-α, interleukin-1α). In short, a "new" BTB is created behind spermatocytes in transit while the "old" BTB above transiting cells undergoes timely degeneration, so that the immunological barrier can be maintained while spermatocytes are traversing the BTB. We also discuss recent findings regarding the molecular mechanisms by which environmental toxicants (e.g., cadmium, bisphenol A) induce testicular injury via their initial actions at the BTB to elicit subsequent damage to germ-cell adhesion, thereby leading to germ-cell loss, reduced sperm count, and male infertility or subfertility. Moreover, we also critically evaluate findings in the field regarding studies on drug transporters in the testis and discuss how these influx and efflux pumps regulate the entry of potential nonhormonal male contraceptives to the apical compartment to exert their effects. Collectively, these findings illustrate multiple potential targets are present at the BTB for innovative contraceptive development and for better delivery of drugs to alleviate toxicant-induced reproductive dysfunction in men.

DESTAF: a database of text-mined associations for reproductive toxins potentially affecting human fertility

The Dragon Exploration System for Toxicants and Fertility (DESTAF) is a publicly available resource which enables researchers to efficiently explore both known and potentially novel information and associations in the field of reproductive toxicology. To create DESTAF we used data from the literature (including over 10500 PubMed abstracts), several publicly available biomedical repositories, and specialized, curated dictionaries. DESTAF has an interface designed to facilitate rapid assessment of the key associations between relevant concepts, allowing for a more in-depth exploration of information based on different gene/protein-, enzyme/metabolite-, toxin/chemical-, disease- or anatomically centric perspectives. As a special feature, DESTAF allows for the creation and initial testing of potentially new association hypotheses that suggest links between biological entities identified through the database. DESTAF, along with a PDF manual, can be found at http://cbrc.kaust.edu.sa/destaf. It is free to academic and non-commercial users and will be updated quarterly.