Mancozeb exposure in vivo impairs mouse oocyte fertilizability

Effects of glyphosate, mancozeb and their combinations on mouse neuroblastoma cells

Pesticides-related toxicities have long been studied. Data regarding the effects of combined exposure to environmentally relevant pesticides however remain lacking. The herbicide glyphosate and the fungicide mancozeb are extensively used in agriculture. Residues of both compounds are frequently found in food and water and therefore, environmental exposure to both pesticides is a possibility. Neurotoxicity of glyphosate, mancozeb and their combinations were investigated using mouse neuroblastoma cells. Cytotoxicity observed with the glyphosate and mancozeb combinations was higher than that observed when glyphosate was tested alone. Combinations of glyphosate followed by mancozeb increased copper, manganese, and zinc levels. Mixture of mancozeb + glyphosate increased manganese and zinc levels. Combination of mancozeb followed by glyphosate increased copper and zinc levels. Glutathione ratio was decreased as a result of combinations of glyphosate and mancozeb. The decrease in glutathione ratio was greater in the combination groups than in glyphosate alone.

Ultrastructural Evaluation of Mouse Oocytes Exposed In Vitro to Different Concentrations of the Fungicide Mancozeb

Mancozeb is a widely used fungicide, considered to be an endocrine disruptor. In vivo and in vitro studies evidenced its reproductive toxicity on mouse oocytes by altering spindle morphology, impairing oocyte maturation, fertilization, and embryo implantation. Mancozeb also induces dose-dependent toxicity on the ultrastructure of mouse granulosa cells, including chromatin condensation, membrane blebbing, and vacuolization. We evaluated the effects on the ultrastructure of mouse oocytes isolated from cumulus-oocyte complexes (COCs), exposed in vitro to increasing concentrations of mancozeb. COCs were matured in vitro with or without (control) low fungicide concentrations (0.001-1 μg/mL). All mature oocytes were collected and prepared for light and transmission electron microscopy. Results showed a preserved ultrastructure at the lowest doses (0.001-0.01 μg/mL), with evident clusters of round-to-ovoid mitochondria, visible electron-dense round cortical granules, and thin microvilli. Mancozeb concentration of 1 μg/mL affected organelle density concerning controls, with a reduction of mitochondria, appearing moderately vacuolated, cortical granules, and microvilli, short and less abundant. In summary, ultrastructural data revealed changes mainly at the highest concentration of mancozeb on mouse oocytes. This could be responsible for the previously described impaired capability in oocyte maturation, fertilization, and embryo implantation, demonstrating its impact on the reproductive health and fertility.

Mancozeb induces nephrotoxicity by impairing the oxidative phosphorylation pathway: A transcriptome study

This study analyzed the mechanism underlying mancozeb (MCZ)-induced kidney injury by detecting kidney function indicators, combined with transcriptome and metabolome sequencing. Twenty mice were randomly assigned into two groups (control and MCZ groups) to explore the MCZ-induced kidney toxicity. The control group was gavaged with 0.2 mL of deionized water, and the MCZ group with 0.2 mL of 100 mg/kg MCZ for 30 days. The kidney structure of the MCZ group was damaged, with slight hyaline degeneration in the kidney tubular epithelial envelope. The creatinine (CRE) and uric acid (UA) were significantly increased in the MCZ group than in the control group. Moreover, the reactive oxygen species (ROS) significantly accumulated in the MCZ group kidneys. Compared to the control group, superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) were significantly decreased in the MCZ group, while the MDA content was substantially increased. The differentially expressed genes (DEGs) in the MCZ group were mainly enriched in the oxidative phosphorylation pathway. Besides, in the MCZ group, ndufs1 and ndufab1 genes were significantly up-regulated, while cox5b, ndufa5, and ndufa6 genes were significantly down-regulated, consistent with the PCR verification results. The metabolomic analysis identified cGMP-PKG signaling pathway of MCZ-induced nephrotoxicity, with Guanosine monophosphate and Adenosine 5'-monophosphate as the main altered metabolites. These results indicated that MCZ impairs the mice kidneys by obstructing the oxidative phosphorylation pathway, which increases oxidative stress in the kidneys, resulting in kidney injury.

Histopathological, immunohistochemical and biochemical alterations in liver tissue after fungicide-mancozeb exposures in Wistar albino rats

PURPOSE

To evaluate the histopathological, immunohistochemical, and biochemical effects of liver changes after mancozeb administration.

METHODS

Rats were divided into groups-the control group (n=7) and the mancozeb group (n=7)-, given 500 mg/kg mancozeb dissolved in corn oil daily for four weeks by an orogastric tube. Caspase-3 and tumor necrosis factor-alpha (TNF-α) primary antibodies were used for immunohistochemical analysis.

RESULTS

Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) values of the mancozeb group increased significantly than ones of the control group. Venous dilatation, inflammation, hepatocyte degeneration, TNF-α, and caspase-3 expression scores increased significantly in the mancozeb group. In the mancozeb group, intensive caspase-3 expression was observed in hepatocyte cells around the central vein in the center of the liver lobule, and there was an increase in TNF-α expression in the inflammatory cells around the enlarged central vein and Kupffer cells and apoptotic hepatocyte cells.

CONCLUSIONS

Subacute mancozeb exposure in rats leads to elevated toxicity with impaired liver function, increased inflammation in tissue and increased apoptosis due to cellular damage in the liver, and decreased liver regeneration ability due to congestion and degeneration of blood vessels.

Impact of Environmental Pollution on Female Reproduction

The increased pollution in the world atmosphere is a global concern. Water, air, and soil are polluted by various sources, such as farm fertilizer, sewage industrial waste products, fumes, and plastics, which in turn impact human health. Plastics and other mixtures of waste affect live in the water. Moreover, the ecosystem is disrupted by the use of heavy metal-containing chemicals in agriculture, and those are eventually consumed by humans. The consequences are a significant negative impact on health including reproductive health, which impairs fertility in the human population. Reproductive functions are severely affected by different chemicals which may interfere with hormonal functions. Greater consequences are faced by the women as the number of germ cells present in the ovary is fixed during fetal life, and which are nonrenewable. From the production of ovum to fertilization, to implantation, and finally continuation of pregnancy, all are affected by the heavy metals and endocrine disruptors. Lifestyle modifications such as consumption of organic foods, plastic product avoidance, separation of residential areas from industrial/agricultural areas, proper waste disposal, and so on, may help to improve the situation.

In vivo and in vitro postovulatory aging: when time works against oocyte quality?

In mammalian species an optimal fertilization window during which successful fertilization occurs. In the majority of mammals estrus marks ovulation time and coincident with mating, thereby allowing the synchronized meeting in the fallopian tubes, between freshly ejaculated sperm and freshly ovulated oocytes. Conversely, women do not show natural visual signs of ovulation such that fertilization can occur hours later involving an aged oocyte and freshly ejaculated spermatozoa. During this time, the oocyte undergoes a rapid degradation known as “postovulatory aging” (POA). POA may become particularly important in the human-assisted reproductive technologies, as the fertilization of retrieved mature oocytes can be delayed due to increased laboratory workload or because of unforeseeable circumstances, like the delayed availability of semen samples. This paper is an updated review of the consequences of POA, either in vivo or in vitro, on oocyte quality with particular attention to modifications caused by POA on oocyte nuclear, cytoplasmic, genomic, and epigenetic maturation, and embryo development.

Impairment of caprine oocyte maturation in vitro and alteration of granulosa cells functions by widely used fungicide mancozeb

Mancozeb is classified as an endocrine disruptor; thus the present study was carried out to investigate the impact of mancozeb on mammalian ovarian functions using in vitro caprine oocyte maturation and granulosa cell culture models. Caprine cumulus oocyte complexes (COCs) and granulosa cells were cultured under standard culture conditions and treated with mancozeb concentrations of 0.3, 3, and 30 μg/ml along with a control for 24 h and assessed. Granulosa cell viability and progesterone concentration in spent culture media after treatments were also assessed. Mancozeb significantly decreased (P < 0.05) the oocytes cumulus expansion and the maturation of caprine oocytes. Marked changes in granulose cell morphology were observed with 30 μg/ml mancozeb and significantly reduced (P < 0.05) cell viability. Interestingly, the same concentrations significantly increased (P < 0.05) the progesterone secretion by the cells. Significant reduction of granulosa cells viability and reduction of cumulus expansion and suppression of metaphase plate formation in oocyte can impair the fertilization ability and developmental potential of the oocytes. High progesterone concentration due to mancozeb treatment may suppress LH surge and suppress ovulation. In conclusion, mancozeb suppresses granulosa cells viability, reduces cumulus expansion, and suppresses metaphase plate formation but induces progesterone secretion from granulosa cells that may inhibit LH surge for ovulation process.

The fungicide Mancozeb reduces spheroid attachment onto endometrial epithelial cells through downregulation of estrogen receptor β and integrin β3 in Ishikawa cells

Mancozeb is a metal-containing ethylene bis-dithiocarbamate fungicide widely used in agriculture. Ethylene thiourea (ETU) is the primary metabolite of Mancozeb. Mancozeb has been associated with spontaneous abortions and abnormal menstruation in women. However, the effects of Mancozeb and ETU on embryo attachment remain unknown. The human blastocyst surrogate trophoblastic spheroids (JEG-3), endometrial epithelial surrogate adenocarcinoma cells (Ishikawa), or human primary endometrial epithelial cells (EECs) monolayer were used in the spheroid attachment models. Ishikawa and EECs were pretreated with different concentrations of Mancozeb or ETU for 48 h before the attachment assay. Gene expression profiles of Ishikawa cells were examined to understand how Mancozeb modulates endometrial receptivity with Microarray. The genes altered by Mancozeb were confirmed by qPCR and compared with the ETU treated groups. Mancozeb and ETU treatment inhibited cell viability at 10 μg/mL and 5000 µg/mL, respectively. At non-cytotoxic concentrations, Mancozeb at 3 μg/mL and ETU at 300 μg/mL reduced JEG-3 spheroid attachment onto Ishikawa cells. A similar result was observed with human primary endometrial epithelial cells. Mancozeb at 3 μg/mL modified the transcription of 158 genes by at least 1.5-fold in Microarray analysis. The expression of 10 differentially expressed genes were confirmed by qPCR. Furthermore, Mancozeb decreased spheroid attachment possibly through downregulating the expression of endometrial estrogen receptor β and integrin β3, but not mucin 1. These results were confirmed in both overexpression and knockdown experiments and co-culture assay. Mancozeb but not its metabolite ETU reduced spheroid attachment through modulating gene expression profile and decreasing estrogen receptor β and integrin β3 expression of endometrial epithelial cells.

Endocrine-disrupting activity of mancozeb

The objective of the present study was to review the existing data on the mechanisms involved in the endocrine disrupting activity of mancozeb (MCZ) in its main targets, including thyroid and gonads, as well as other endocrine tissues that may be potentially affected by MCZ. MCZ exposure was shown to interfere with thyroid functioning through impairment of thyroid hormone synthesis due to inhibition of sodium-iodine symporter (NIS) and thyroid peroxidase (TPO) activity, as well as thyroglobulin expression. Direct thyrotoxic effect may also contribute to thyroid pathology upon MCZ exposure. Gonadal effects of MCZ involve inhibition of sex steroid synthesis due to inhibition of P450scc (CYP11A1), as well as 3β-HSD and 17β-HSD. In parallel with altered hormone synthesis, MCZ was shown to down-regulate androgen and estrogen receptor signaling. Taken together, these gonad-specific effects result in development of both male and female reproductive dysfunction. In parallel with clearly estimated targets for MCZ endocrine disturbing activity, namely thyroid and gonads, other endocrine tissues may be also involved. Specifically, the fungicide was shown to affect cortisol synthesis that may be mediated by modulation of CYP11B1 activity. Moreover, MCZ exposure was shown to interfere with PPARγ signaling, being a key regulator of adipogenesis. The existing data also propose that endocrine-disrupting effects of MCZ exposure may be mediated by modulation of hypothalamus-pituitary-target axis. It is proposed that MCZ neurotoxicity may at least partially affect central mechanisms of endocrine system functioning. However, further studies are required to unravel the mechanisms of MCZ endocrine disrupting activity and overall toxicity.

Female Fertility and Environmental Pollution

A realistic picture of our world shows that it is heavily polluted everywhere. Coastal regions and oceans are polluted by farm fertilizer, manure runoff, sewage and industrial discharges, and large isles of waste plastic are floating around, impacting sea life. Terrestrial ecosystems are contaminated by heavy metals and organic chemicals that can be taken up by and accumulate in crop plants, and water tables are heavily contaminated by untreated industrial discharges. As deadly particulates can drift far, poor air quality has become a significant global problem and one that is not exclusive to major industrialized cities. The consequences are a dramatic impairment of our ecosystem and biodiversity and increases in degenerative or man-made diseases. In this respect, it has been demonstrated that environmental pollution impairs fertility in all mammalian species. The worst consequences are observed for females since the number of germ cells present in the ovary is fixed during fetal life, and the cells are not renewable. This means that any pollutant affecting hormonal homeostasis and/or the reproductive apparatus inevitably harms reproductive performance. This decline will have important social and economic consequences that can no longer be overlooked.

In vitro and in vivo impairment of embryo implantation by commonly used fungicide Mancozeb

The fungicide Mancozeb is an endocrine-disrupting chemical and the mode of action of Mancozeb on embryo implantation is largely unknown. Mancozeb (1 and 3 μg/ml) significantly reduced Jeg-3 trophoblastic spheroids attachment to endometrial epithelial Ishikawa cells. Mancozeb treatment from gestation day (GD) 1 to GD8 or from GD4 to GD8 significantly lowered the number of implantation sites with higher incidence of morphological abnormalities in the reproductive tissues. However, these were not seen in the treatment from GD1 to GD4. Mancozeb at 30 mg/kg BW/d did not alter the expression of p53, COX-2, or PGFS transcripts in the uterus, but down-regulated the PGES transcript and protein. Mancozeb treatment in human endometrial stromal cells did not alter the decidualization response, but the morphological transformation was impaired. Taken together, exposure to Mancozeb affected embryo implantation probably through the modulation of decidualization and to delineate the exact mode of action needs further investigations.

Association between Female Reproductive Health and Mancozeb: Systematic Review of Experimental Models

Mancozeb is a widely used fungicide approved for use in agriculture in many countries with long persistence in the environment and consequent bioaccumulation in tissues and biological fluids. Despite the large amount of studies published in recent years, the relationship between mancozeb exposure and female reproductive health is not fully elucidated. In order to summarize current evidence on mancozeb exposure and female reproductive disease, we performed a systematic review of literature. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to make this review. An adapted version of the National Toxicology Program’s Office of Health and Assessment and Translation (OHAT) framework was used to evaluate the risk of bias. Electronic search on two databases (PubMed and Scopus) was used to find experimental studies (in vitro and in vivo) on mancozeb exposure. The database search identified 250 scientific articles, 20 of which met our inclusion criteria. Selected data were then reviewed and summarized in tables. Overall, mancozeb represents a hazard for female reproductive health, with different mechanisms of action. Undoubtedly more experimental and epidemiological studies are required to definitively validate mancozeb as reproductive toxicant.

Mancozeb exposure during development and lactation periods results in decreased oocyte maturation, fertilization rates, and implantation in the first-generation mice pups: Protective effect of vitamins E and C

This study aimed to evaluate the mancozeb (MNZ) impact on oocyte maturation of first-generation mice pups as well as their fertilization rate, embryo development, and implantation along with the preventative effect of vitamins E and C. Pregnant mice were randomly divided into six groups: control, vehicle, and MNZ (500 mg/kg body weight (BW)), vitamin E (200 mg/kg BW), MNZ plus vitamin E, MNZ plus vitamin C (100 mg/kg BW), and MNZ plus two vitamins. All treatments were conducted by oral gavage every 2 days from the second day of gestation until the end of lactation. Vitamin treatment was initiated 30 min before receiving MNZ. After birth, first-generation mice pups were kept until adulthood (8-10 W). Adult female mice pups superovulated and then the collected oocytes were examined for nuclear maturity status. After in vitro fertilization of metaphase II oocytes with sperm of the first-generation male mice pups, fertilization rate and embryo development were evaluated over 24 h. Also, the fecundity rate and the number of implanted embryos in vivo were studied on the eighth day of pregnancy. MNZ exposure during embryo development and lactation significantly decreased the total number of collected oocytes, oocyte maturation, fertilization rate, implantation rate, fecundity rate, and embryo development compared with the control group in the first-generation pups. In contrast, vitamin treatments significantly increased these parameters compared to the MNZ group. Reduction in the quality of oocyte, the rate of fertilization, embryo implantation, and development following MNZ exposure could decrease female reproductive success, while coadministration of vitamins E and C could prevent these complications.

Curcumin mitigates mancozeb-induced hepatotoxicity and genotoxicity in rats

Mancozeb (MZ) is a widely used ethylene-bis-dithiocarbamate fungicide in agriculture causing hepatoxic and genotoxic effects in rats. Curcumin (CUR) has various pharmacological effects including antioxidant and anti-inflammatory properties. This study investigated the efficacy of CUR in mitigating MZ-induced hepatotoxicity and genotoxicity in rats. Twenty-four male rats were divided into four equal groups; group I (control) was given carboxymethyl cellulose, group II was orally administered CUR (100 mg/kg b.wt), group III was gavaged with MZ (750 mg/kg b.wt), and group IV was co-treated with MZ and CUR at the same doses daily for 10 weeks. As a result, the concurrent treatment with CUR and MZ minimized the increased levels of liver function markers in serum, lipid peroxidation, pro-inflammatory mediators and DNA damage parameters in liver. In addition, CUR administration improved the depleted markers of hepatic antioxidant status in MZ-treated rats. Moreover, CUR protected the liver against the histological alterations elicited by MZ exposure and also, reduced the immunopositive reactivity of pro-apoptotic p53 in cytoplasm of hepatocytes. The present findings suggest that CUR exerts a significant protective effect against MZ-induced hepatotoxicity and genotoxicity.

Preventative Effects of Vitamin E on Testicular Damage and Sperm Parameters in the First-Generation Mice Pups due to Pre- and Postnatal Mancozeb Exposure

The present study aimed to evaluate the effects of vitamin E on mancozeb-induced testis damage of the first-generation pups during intrauterine and lactating periods. Two groups of pregnant NMRI mice received 500 mg/kg mancozeb (MNZ) as MNZ group and 200 mg/kg vitamin E as MNZ+vit.E group before receiving MNZ. In addition, a vehicle and a control group were designed every other day in gestation and lactation periods. The male pups from each group were maintained until adulthood (8-10 W). The left testes and epididymides were removed following the sacrifice of the pups. Then, they were weighed, and sperm parameters including number, viability, motility, and morphology and testis structure were evaluated. A significant decrease occurred in sperm parameters of the mancozeb-treated pups compared to the control and vehicle groups. Treatment with vitamin E reversed the deleterious effects of MNZ to a nearly normal condition. Testis parameters including the weight, gonadosomatic index, seminiferous tubule diameters, and Johnsen's score, as well as the number of germ cells such as spermatogonia, spermatocyte, spermatid, and Sertoli, decreased significantly in the MNZ group, compared to the amount in the control and vehicle groups. Interestingly, the treatment with vitamin E was reversed in most of these parameters. Based on the results, the exposure of pups to mancozeb during pregnancy and lactating periods negatively affects the reproductive system of male pups. However, the coadministration of vitamin E could prevent the deleterious effects of mancozeb on sperm and testis parameters.

Technologies for the Production of Fertilizable Mammalian Oocytes

Women affected by ovarian pathologies or with cancer can usually preserve fertility by egg/embryo freezing. When oocyte retrieval is not feasible, the only option available is ovarian tissue cryopreservation and transplantation. The culture of follicles isolated from fresh or cryopreserved ovaries is considered still experimental, although this procedure is considered safer, because the risk of unintentional spreading of cancer cells eventually present in cryopreserved tissue is avoided. Animal and human small follicles can be cultured in vitro, but standardized protocols able to produce in vitro grown oocytes with the same developmental capacity of in vivo grown oocytes are not available yet. In fact, the different sizes of follicles and oocytes, the hormonal differences existing between mono- (e.g., human, goat, cow, and sheep) and poly-ovulatory (rodents and pig) species, and the incomplete identification of the mechanisms regulating the oocyte–follicle and follicle–ovary interrelationships affect the outcome of in vitro culture. From all these attempts, however, new ideas arise, and the goal of assuring the preservation of female reproductive potential appears a more realistic possibility. This review surveys and discusses advances and challenges of these technologies that, starting from a simple attempt, are now approaching the biosynthesis of a functional engineered ovary.

Vitamins E and C prevent apoptosis of testicular and ovarian tissues following mancozeb exposure in the first-generation mouse pups

The aim of this study was to evaluate the role of apoptosis in the first-generation pups' testicular and ovarian tissue changes following mancozeb (MNZ) administration during intrauterine and lactating periods and also the preventive effect of the co-administration of vitamins E and C on these changes. Naval Medical Research Institute (NMRI) pregnant mice were randomly divided into six groups: control, vehicle, MNZ, vitamin E plus MNZ, vitamin C plus MNZ and vitamins E and C plus MNZ. Administered doses of MNZ and vitamins E and C were 500, 200 and 100 mg/kg of body weight, respectively. These agents were administered to the animals by oral gavage every 2 days. Vitamin treatment was carried out 30 min prior to MNZ administration. Treatment was started on the second day of gestation and continued until weaning. Separated testes and ovaries of animals were prepared for apoptosis detection by terminal deoxynucleotidyl transferase end-labeling (TUNEL) staining. The percentage of TUNEL-positive cells was reported using the 4,6-diamidino-2-phenylindole method. As compared to the control and vehicle groups, MNZ induced a significant increase ( p < 0.001) in the number of TUNEL-positive cells. The administration of both vitamins E and C alone and together significantly ( p < 0.001) prevented the apoptotic impacts of MNZ. The preventive effect of the co-administration of these vitamins on the ovary was greater compared to the single administration of vitamins E ( p < 0.001) or C ( p < 0.001). Meanwhile, the results revealed the stronger preventive effect of vitamin C as compared to E on testicular tissue ( p < 0.05). The apoptotic impact of MNZ exposure during intrauterine and lactating periods on first-generation testicular and ovarian tissues was significant. The co-administration of vitamins E and C could prevent MNZ-induced testicular and ovarian changes.

Transcriptional landscape of mouse-aged ovaries reveals a unique set of non-coding RNAs associated with physiological and environmental ovarian dysfunctions

The progressive and physiological decline in ovarian function depends on the rate of follicular loss by atresia, contributing to the reduction in ovarian reserve. Genetics and environmental factors play important roles in ovarian senescence and in the onset of ovarian dysfunctions such as diminished ovarian reserve. A better understanding of the mechanisms underlying ovarian aging and their regulation by genetic and environmental factors is needed to evaluate ovarian reserve and to predict fertility potential by identification of more accurate and less invasive markers. We report transcriptomic data (i) implicating novel (e.g. EIF2 signalling) and well-known pathways (e.g. TGFβ signalling), and (ii) defining a unique set of non-coding RNA (ncRNA), both associated with ovarian function. The latter includes miRNAs (e.g. Mir143 and Mir145), snoRNAs (e.g. Snord16a and Snora34), and one lncRNA (Gas5), which are differentially expressed in middle-aged ovaries (12 months) vs young-aged (3 months) from CD1 mice. Experimental analysis confirms that ovary lifespan varies across genetic backgrounds in mice and, genetics influences the response to environmental perturbations such as diet. Moreover, the identified ncRNAs were verified in a model of reproductive dysfunction promoted by the environmental toxicant ethylenthiourea. We also report the increase of miRNA143 and miRNA145 in follicular fluid of women with diminished ovarian reserve. Their levels inversely correlate with the hormonal profile and with the number of the oocytes recruited upon hormonal stimulation. Overall, we report a transcriptomic signature for ovarian dysfunction in vivo that provides a valuable resource for translational research in human reproductive aging.

Protective effects of resveratrol against mancozeb induced apoptosis damage in mouse oocytes

Mancozeb, a mixture of ethylene-bis-dithiocarbamate manganese and zinc salts, is one of the most widely used fungicides in agriculture. Mancozeb could lead to mitochondria dysfunction, cellular anti-oxidation enzymes depletion and apoptotic pathways activation. Previous studies indicated the exposure of mancozeb through mother would lead to irregular estrous cycles, decreased progesterone levels, reduced litter sizes, and more frequent delivery of dead fetuses. In this study, we investigated mancozeb inducing reproductive toxicity, especially focusing on its apoptotic effect and epigenetic modifications. We also showed that resveratrol, a kind of phytoalexin found in peanuts and grapes, can alleviate mancozeb's adverse effects, such as declined fertility, decreased ovary weight and primary follicles. Besides, mancozeb treated oocytes displayed suboptimal developmental competence and this can also be improved by treatment of resveratrol. More detailed investigation of these processes revealed that mancozeb increased reactive oxygen species, causing cell apoptosis and abnormal epigenetic modifications, and resveratrol can block these cytotoxic changes. Collectively, our results showed that resveratrol can alleviate mancozeb induced infertility and this was mainly through the correction of apoptotic tendency and the abnormity of cellular epigenetic modification.

Mancozeb impairs the ultrastructure of mouse granulosa cells in a dose-dependent manner

Mancozeb, an ethylene bis-dithiocarbamate, is widely used as a fungicide and exerts reproductive toxicity in vivo and in vitro in mouse oocytes by altering spindle morphology and impairing the ability to fertilize. Mancozeb also induces a premalignant status in mouse granulosa cells (GCs) cultured in vitro, as indicated by decreased p53 expression and tenuous oxidative stress. However, the presence and extent of ultrastructural alterations induced by mancozeb on GCs in vitro have not yet been reported. Using an in vitro model of reproductive toxicity, comprising parietal GCs from mouse antral follicles cultured with increasing concentrations of mancozeb (0.001–1 µg/ml), we sought to ascertain the in vitro ultrastructural cell toxicity by means of transmission (TEM) and scanning (SEM) electron microscopy. The results showed a dose-dependent toxicity of mancozeb on mouse GCs. Ultrastructural data showed intercellular contact alterations, nuclear membrane irregularities, and chromatin marginalization at lower concentrations, and showed chromatin condensation, membrane blebbing, and cytoplasmic vacuolization at higher concentrations. Morphometric analysis evidenced a reduction of mitochondrial length in GCs exposed to mancozeb 0.01−1 µg/ml and a dose-dependent increase of vacuole dimension. In conclusion, mancozeb induced dose-dependent toxicity against GCs in vitro, including ultrastructural signs of cell degeneration compatible with apoptosis, likely due to the toxic breakdown product ethylenethiourea. These alterations may represent a major cause of reduced/delayed/missed oocyte maturation in cases of infertility associated with exposure to pesticides.

A systematic review of Mancozeb as a reproductive and developmental hazard

BACKGROUND

The potential adverse reproductive and developmental effects of Mancozeb, especially in sensitive subpopulations, have not been fully reviewed for this widely used fungicide.

OBJECTIVE

To review the experimental and epidemiologic evidence for the association between exposure to Mancozeb and reproductive and developmental health outcomes using an adaptation of the National Toxicology Program's Office of Health Assessment and Translation (OHAT) systematic review framework.

DATA SOURCES

Four databases (PubMed, TOXNET, Web of Science, Google Scholar) were searched for published studies on Mancozeb. Of 403 identified articles, 30 met our inclusion criteria for systematic review.

RESULTS

Results from in vitro studies provide evidence that Mancozeb may indirectly disrupt or impair reproduction at the cellular level and should be regarded as a reproductive toxicant. Animal studies confirm reproductive and developmental toxicity in mammals and suggest that males chronically exposed to Mancozeb experience significant changes in physiological, biochemical, and pathological processes that may lead to infertility. Epidemiological studies were limited to indirect methods of exposure assessment and examined the effect of fungicides more broadly during pre-conception, pregnancy, and birth, yielding mixed results.

CONCLUSIONS

High confidence ratings from in vitro and animal studies, in combination with moderate confidence ratings from epidemiologic studies employing indirect methods of exposure assessment, provide evidence that Mancozeb should be regarded as a suspected developmental hazard and a presumed reproductive hazard in humans. More population-based studies linking direct measures and/or biomarkers of exposure to adverse effects on male and female fertility, as well as in utero and early life development, are needed to improve the quality of the evidence base concerning the human reproductive and developmental consequences of Mancozeb exposure.

Mancozeb, a fungicide routinely used in agriculture, worsens nonalcoholic fatty liver disease in the human HepG2 cell model

Mancozeb, a manganese/zinc ethylene-bis-dithiocarbamate, is a fungicide routinely used in pest control programs. However, it has been found to have deleterious effects on human health and on the environment. Indeed, its massive use has raised the issue of possible health risks for agrarian communities; the molecule can also reach human cells via the food chain and alter metabolism, endocrine activity and cell survival. In particular, mancozeb induces many toxic effects on hepatic cell metabolism. For this reason, we investigated its effect in an in vitro model of hepatic damage, namely fatty acid-induced nonalcoholic fatty liver disease in the HepG2 cell line. We found that the hepatic toxicity of the fungicide exacerbated fatty acid-induced steatosis, as manifested by an increase in intracellular lipid droplet accumulation. Furthermore, mancozeb altered cell metabolism and induced cell death through upregulation of lactate dehydrogenase and cytochrome c, respectively, in dose-dependent manners. Therefore, mancozeb may play an important role in the pathogenesis and progression of chronic disease in humans and represents a danger for human health in high doses.

Mancozeb affects mitochondrial activity, redox status and ATP production in mouse granulosa cells

BACKGROUND

Mancozeb (MZ) is a fungicide that belongs to the subclass of metal (Mn/Zn) ethylene-bis-dithiocarbamate pesticides. In mouse and human granulosa cells (GCs) exposed to MZ (0.01 μg/ml), morphological modifications and significant alterations of p53 expression level in comparison with control GCs were recorded.

OBJECTIVES

To investigate if MZ (0.01 μg/ml) induces oxidative stress and alters energy metabolism in exposed mouse GCs.

RESULTS

Following fungicide exposure, GCs showed low p53 content, a depolarized mitochondrial membrane potential (ΔΨm), as well as low ATP and reduced glutathione (GSH) levels associated with increased reactive oxygen species (ROS) generation. No remarkable differences on other parameters such as ATP/ADP ratio, energy charge, as well as induction of apoptosis and DNA damage were found. The activation of AKT and PDK1 kinases in MZ-treated cells was observed. Inhibition of ROS generation by the antioxidant N-acetylcysteine (NAC) restored a normal expression level of p53.

CONCLUSIONS

Our results demonstrate that the low dose of MZ here used induces a mild oxidative stress in GCs, and provides evidence for the possible involvement of AKT/PKB signaling pathway in triggering adaptive and survival response.

Pesticide-induced decrease in rat testicular steroidogenesis is differentially prevented by lipoate and tocopherol

We have previously demonstrated that the sub-chronic administration of low doses of Toc or α-Toc, glyphosate and zineb to rats (i.p. 1/250 LD50, three times a week for 5 weeks) provoked severe oxidative stress (OS) in testicles. These effects were also reflected in plasma. Lipoic acid (LA) and α-tocopherol are considered as antioxidants due to their ability to neutralize reactive oxygenated species (ROS) and reset endogenous antioxidant levels. To investigate the possible protective effect on reproductive function, LA and Toc (i.p. 25, 50 and 100mg/kg) were administered simultaneously with the pesticide mixture (PM) for 5 weeks. Both drugs prevented OS and the damage to proteins and lipids caused by PM in a dose-dependent manner. The PM-induced increase levels of prostaglandins E2 and F2α was completely restored by LA but not by Toc. Similarly, only LA was able to restore the inhibition of testosterone production, the decrease of 3β- and 17β-hydroxysteroid dehydrogenases activities, and the elevation of gonatropins (FSH and LH) levels produced by PM. Furthermore, LA was more efficient than Toc in normalizing the histological alterations produced by PM administration, suggesting that pesticides act though other mechanisms that generate oxidative stress. In our experimental model LA displayed a higher protective role against pesticide-induced damage than that observed by Toc administration. Our results suggest that LA administration is a promising therapeutic strategy for coping with disorders suspected to be caused by OS generators - such as pesticides - in male reproductive system.

Effects of trifluralin on the mouse ovary

Trifluralin, a herbicide used to protect many arable and horticultural crops, was evaluated for its potential toxicity on the mammalian ovary. To this end, adult female mice were fed or not (control) with a trifluralin-enriched diet (150 mg/kg body weight/day) during gestation and lactation. After weaning, 3-week-old female mice from either trifluralin-treated or control groups were used to evaluate whether the exposure to this herbicide in utero and during lactation could induce stress responses in the ovary. It was found that trifluralin exposure caused a significantly higher level of p53, but not of pRb, in the whole ovary, and in particular in granulosa cells. TUNEL staining showed that herbicide treatment did not increase the apoptotic index of the somatic compartment. Also oocyte fertilizability was unaffected, as metaphase II oocytes retrieved from treated mice were capable of forming male and female pronuclei after in vitro fertilization as control mice. However, trifluralin determined a slightly higher number of oocytes with cytoplasmic degeneration compared with control animals. In conclusion, our results suggest that exposure to a low trifluralin dose during pregnancy and lactation does not impair oocyte quality, but can induce a stress response in ovarian somatic cells.

Exposure to the widely used fungicide mancozeb causes thyroid hormone disruption in rat dams but no behavioral effects in the offspring

The widely used fungicide mancozeb has been shown to cause hypothyroxinemia and other adverse effects on the thyroid hormone system in adult experimental animals. In humans, hypothyroxinemia early in pregnancy is associated with adverse effects on the developing nervous system and can lead to impaired cognitive function and motor development in children. The aim of the present study was therefore to assess whether perinatal mancozeb exposure would cause developmental neurotoxicity in rats. Groups of 9-21 time-mated Wistar rats were dosed with 0, 50, 100, or 150 mg mancozeb/kg body weight (bw)/day by gavage from gestation day (GD) 7 to postnatal day (PND) 16, and total thyroxine (T(4)) levels were measured in dams during gestation. On PND 16, hormone levels and several organ weights were measured in the offspring, whereas motor activity, startle response, and cognitive function were assessed in the adult offspring. The dose of 150 mg/kg/day caused neurotoxicity in the pregnant dams and was therefore reduced to 100 mg/kg bw/day in mid study. T(4) levels showed a dose-dependent and significant decrease in dams from all three dose groups on GD 15, whereas offspring T(4) levels, thyroid weights, and histology were unaffected on PND 16. No effects on reproductive organ weights were seen, and no behavioral changes were observed. Taken together, these results indicate that in rats, moderate maternal hypothyroxinemia during gestation does not necessarily lead to hyperactivity or reduced special learning abilities in the offspring. Mancozeb exposure did, however, reduce T(4) levels in dams and may therefore still be a potential contributor to thyroid disruption in humans and in result adversely affects the developing brain.

Mancozeb adversely affects meiotic spindle organization and fertilization in mouse oocytes

In this study the effects of mancozeb, a widely used ethylenebisdithiocarbamate fungicide, on mouse oocyte meiotic maturation and fertilization were analyzed. Oocyte cumulus cell-complexes were matured in vitro with or without increasing concentrations of the fungicide (from 0.001 to 1 microg/ml) that, due to its different stability in organic solvents and in water, was resuspended either in dimethyl sulfoxide or in culture medium. Although, about 95% of oocytes reached the metaphase II stage; mancozeb-exposed oocytes showed a dose-dependent increase of alterations in spindle morphology, and this negative effect was more evident when the fungicide was resuspended in culture medium. Under the latter culture condition, oocytes matured in the presence of 0.1 and 1 microg/ml mancozeb showed a significant reduction also in the formation of male and female pronuclei. These results indicate that mancozeb can adversely affect mammalian reproductive performance, likely by perturbing microtubular organization during meiotic maturation.