The environment and female reproduction: Potential mechanism of cadmium poisoning to the growth and development of ovarian follicle

Association Between Exposure to Multiple Toxic Metals in Follicular Fluid and the Risk of PCOS Among Infertile Women: The Mediating Effect of Metabolic Markers

Polycystic ovary syndrome (PCOS) severely affects women's fertility and accompanies serious metabolic disturbances, affecting 5%-20% of women of reproductive age globally. We previously found that exposure to toxic metals in the blood raised the risk of PCOS, but the association between exposure to toxic metals and the risk of PCOS in the follicular fluid, the microenvironment for oocyte growth and development in females, and its effect on metabolism has not been reported. This study aimed to evaluate the associations between the concentrations of cadmium (Cd), mercury (Hg), barium (Ba) and arsenic (As) in FF and the risk of PCOS, and to explore the mediating effect of metabolic markers in FF on the above relationship. We conducted a case-control study, including 557 women with PCOS and 651 controls. Ba, Cd, Hg and As levels in FF were measured by ICP-MS, metabolites levels in FF was measured by LC-MS/MS among 168 participants randomly selected from all the participants. Logistic regression models were used to assess the association of a single metal level with the PCOS risk, and linear regression models were used to assess the relationships of a single metal level with clinical phenotype parameters and metabolites levels. Combined effect of metals mixture levels on the risk of PCOS were assessed via weighted quantile sum (WQS) regression and bayesian kernel machine regression (BKMR). Medication analysis was performed to explore the role of metabolic markers on the relationship of toxic metals levels with the risk of PCOS. The exposure levels of Cd, Hg, Ba and As in FF were all positively and significantly associated with the PCOS risk (with respect to the highest vs. lowest tertile group: OR = 1.57, 95% CI = 1.17 ~ 2.12 for Cd, OR = 1.69, 95% CI = 1.22 ~ 2.34 for Hg, OR = 1.76, 95% CI = 1.32 ~ 2.34 for Ba, OR = 1.42, 95% CI = 1.05 ~ 1.91 for As). In addition, levels of metal mixture also significantly correlated with the risk of PCOS, Cd level contributed most to it. Moreover, we observed significant positive relationships between Cd level and LH (β = 0.048, 95% CI = 0.002 ~ 0.094), T (β = 0.077, 95% CI = 0.029 ~ 0.125) and HOMA-IR value (β = 0.060, 95% CI = 0.012 ~ 0.107), as well as Hg level with LH, FSH/LH ratio and TC. Furthermore, we revealed that estrone sulfate, LysoPE 22:6 and N-Undecanoylglycine were significantly and positively mediating the association between Cd level and the risk of PCOS (with mediated proportion of 0.39, 0.24 and 0.35, respectively), and between Hg level and the risk of PCOS (with mediated proportion of 0.29, 0.20 and 0.46, respectively). These highly expressed metabolites significantly enriched in the fatty acid oxidation, steroid hormone biosynthesis and glycerophospholipids metabolism, which may explain the reason why the levels of Cd and Hg in FF associated with the phenotype of PCOS. Ba and As in FF was not found the above phenomenon. Our results suggested that exposure to multiple toxic metals (Cd, Hg, Ba and As) in FF associated with the increased risk of PCOS, Cd was a major contributor. Levels of Cd and Hg in FF significantly associated with the phenotype of PCOS. The above association may result from that Cd and Hg in FF related with the disturbance of fatty acid oxidation, steroid hormone biosynthesis and the glycerophospholipids metabolism.

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.

N6-methyladenosine mediated-NRF2 signaling pathway attenuates cadmium cytotoxicity by inhibiting oxidative damage in bronchial epithelial cells

Although N6-methyladenosine (m6A) and its regulatory proteins were involved in multiple cellular damage processes, the roles of m6A and its regulatory proteins in cadmium-induced pulmonary cell damage remain largely unknown. Our present data indicated that cadmium exposure caused serious damage in bronchial epithelial cells, as evidenced by reduction of cell viability and elevation of oxidative damage and apoptosis. These processes were accompanied by alterations of m6A modification and its regulatory proteins (FTO, ALKBH5, YTHDC2). It is noteworthy that pretreatment with the m6A agonist entacapone (ENT) markedly attenuated the detrimental effects of cadmium, including cell death, oxidative damage, and the activation of the nuclear factor erythroid 2-related factor 2 (NRF2）signalling pathway. Conversely, the detrimental effects of CdSO4 were significantly exacerbated when m6A levels were inhibited by 3-deazidyladenosine (DAA). Further prediction result revealed that multiple m6A-modified sites occur on NRF2 mRNA with high confidence level, implicating that m6A modification on NRF2 mRNA may affect the protein expression of NRF2. In conclusion, our data together suggest that m6A modification play critical roles in cadmium-induced bronchial epithelial cell damage, during which NRF2 signaling pathway may act as an important bridge for m6A modification to regulate cellular damage. This study offer a promising avenue for further investigation into the mechanisms underlying cadmium-induced bronchial epithelial cell damage from the perspective of RNA epigenetics.

In Vitro Toxicity of a DEHP and Cadmium Mixture on Sheep Cumulus-Oocyte Complexes

Di-(2-ethylhexyl) phthalate (DEHP) and Cadmium (Cd) affect female reproduction. To date, toxicological research has focused on the effects of individual contaminants, whereas living beings are exposed to mixtures. This study analyzed the effects of a DEHP/Cd mixture on nuclear and cytoplasmic maturation of sheep cumulus-oocyte complexes (COCs) compared with single compounds. COCs recovered from slaughterhouses-derived sheep ovaries were in vitro exposed to 0.5 μM DEHP, 0.1 μM Cd, or DEHP/Cd mixture at the same concentrations during 24 h of in vitro maturation (IVM). After IVM, oocyte nuclear chromatin configuration was evaluated, and bioenergetic/oxidative parameters were assessed on expanded cumulus cells (CCs) and matured oocytes (chi-square test and one-way ANOVA; p < 0.05). Under examined conditions, oocyte nuclear maturation was never impaired. However, COC bioenergetics was affected with stronger effects for the mixture than single compounds. Indeed, the percentages of matured oocytes with healthy mitochondrial distribution patterns were reduced (p < 0.001 and p < 0.05 for mixture and single compounds, respectively). Oocyte mitochondrial membrane potential, intracellular ROS levels, and mitochondria/ROS co-localization were reduced, with the same significance level, in all contaminated conditions. CCs displayed increased ROS levels only upon mixture exposure (p < 0.001). In conclusion, in vitro exposure to the DEHP/Cd mixture affected COC quality in the sheep to a greater extent than separate compounds.

Epigenetic Modifications Are Involved in Transgenerational Inheritance of Cadmium Reproductive Toxicity in Mouse Oocytes

Maternal cadmium exposure during pregnancy has been demonstrated to have detrimental effects on offspring development. However, the impact of maternal cadmium exposure on offspring oocytes remains largely unknown, and the underlying mechanisms are not fully understood. In this study, we found that maternal cadmium exposure during pregnancy resulted in selective alteration in epigenetic modifications of mouse oocytes in offspring, including a decrease in H3K4me2 and H4K12ac, as well as an increase in DNA methylation of H19. Although ROS levels and mitochondrial activity remain at normal levels, the DNA damage marker γH2AX was significantly increased and the DNA repair marker DNA-PKcs was remarkably decreased in offspring oocytes from maternal cadmium exposure. These alterations are responsible for the decrease in the quality of mouse oocytes in offspring induced by maternal cadmium exposure. As a result, the meiotic maturation of oocytes and subsequent early embryonic development are influenced by maternal cadmium exposure. RNA-seq results showed that maternal cadmium exposure elicits modifications in the expression of genes associated with metabolism, signal transduction, and endocrine regulation in offspring ovaries, which also contribute to the disorders of oocyte maturation and failures in early embryonic development. Our research provides direct evidence of transgenerational epigenetic inheritance of cadmium reproductive toxicity in mouse germ cells.

Melatonin prevents histopathologies stem from cadmium chloride in pregnant mice lungs

Heavy metals may cause structural and functional changes in organs. Cadmium, taken into the body through oral and respiratory routes, can lead to lesions. Cadmium may lead to lesions by accumulating in organs. The lungs are significantly affected by cadmium. Melatonin, an antioxidant hormone with therapeutic effects, is secreted by the pineal gland. The aim of the study is to treat cadmium-induced lesions in the lungs of pregnant mice with Melatonin. Four groups were created with 24 pregnant mice, named Control, Cadmium Chloride, Melatonin, and Melatonin + Cadmium Chloride groups (n: 6) Cadmium Chloride (2 mg/kg/bw) and Melatonin (3 mg/kg/bw) were given orally through gavage during pregnancy (21 days) After routine histological procedures, the lung tissues were stained with Hematoxylin-Eosin and evaluated under a light and electron microscope. ANOVA tests were applied for one-way analysis of variance, and LSD tests were applied for pairwise comparisons (p < 0.05) The average lung weight decreased in the Cadmium Chloride group (p: 0.03) The average lung weight in the Cadmium Chloride + Melatonin group was found to be close to the control group (p: 0.06) Cadmium Chloride caused thickening of the lung alveolar wall, inflammatory cell infiltration, and fibrin deposition. Because the lesions were not observed in the Melatonin group, lesions may be prevented by melatonin. Additional studies may be useful to determine the protective effect of Melatonin at different doses of Cadmium Chloride.

Cadmium exposure induces multigenerational inheritance of germ cell apoptosis and fertility suppression in Caenorhabditis elegans

Cadmium is a significant environmental pollutant that poses a substantial health hazard to humans due to its propensity to accumulate in the body and resist excretion. We have a comprehensive understanding of the damage caused by Cd exposure and the mechanisms of tolerance, however, the intricate mechanisms underlying multigenerational effects resulting from Cd exposure remain poorly understood. In this study, Caenorhabditis elegans were used as a model organism to investigate Cd-induced multigenerational effects and its association with epigenetic modifications. The results showed that Cd exposure leads to an increase in germ cell apoptosis and a decrease in fertility, which can be passed down to subsequent generations. Further analysis revealed that transcription factors DAF-16/FOXO and SKN-1/Nrf2 play essential roles in responding to Cd exposure and in the transgenerational induction of germ cell apoptosis. Additionally, histone H3K4 trimethylation (H3K4me3) marks stress-responsive genes and enhances their transcription, ultimately triggering multigenerational germ cell apoptosis. This study provides compelling evidence that the detrimental effects of Cd on the reproductive system can be inherited across generations. These findings enhance our understanding of the multigenerational effects of environmental pollutants and may inform strategies for the prevention and control of such pollutants.

Naringenin mitigates cadmium-induced cell death, oxidative stress, mitochondrial dysfunction, and inflammation in KGN cells by regulating the expression of sirtuin-1

The objective of this study was to examine the potential protective role of naringenin against the harmful effects induced by cadmium in KGN cell line. Cell viability was evaluated by cell counting kit-8 assay. Caspase-3/-9 activities were determined by caspase-3/-9 activity assay kits, respectively. Intracellular reactive oxygen species (ROS) level was detected by ROS-Glo™ H2O2 Assay, antioxidant capacity was determined by a total antioxidant capacity assay kit. Mitochondrial membrane potential (MMP), ATP level, and ATP synthase activity were determined by JC-1, ATP assay kit, and ATP synthase activity assay kit, respectively. The mRNA expression was determined by qRT-PCR. Cadmium reduced cell viability and increased caspase-3/-9 activities in a concentration-dependent manner. Naringenin improved cell viability and reduced caspase-3/-9 activities in cadmium-stimulated KGN cells in a concentration-dependent manner. Cadmium diminished the antioxidant capacity, increased ROS production, and induced mitochondrial dysfunction in KGN cells. These effects were ameliorated by naringenin treatment in a concentration-dependent manner. Furthermore, naringenin reduced the levels of pro-inflammatory cytokines in KGN cells exposed to cadmium. SIRT1 knockdown downregulated its expression in KGN cells and compromised the protective effects of naringenin on cell viability and caspase-3/-9 activities in cadmium-stimulated KGN cells. Naringenin prevented the reduction of MMP, ATP levels, and ATP synthase activity in cadmium-stimulated KGN cells in a concentration-dependent manner. However, these protective effects were significantly reversed by SIRT1 knockdown. In conclusion, this study suggests that naringenin protects against cadmium-induced damage by regulating oxidative stress, mitochondrial function, and inflammation in KGN cells, with SIRT1 playing a potential mediating role.

Protein expression patterns and metal metabolites in a protogynous hermaphrodite fish, the ricefield eel (Monopterus albus)

BACKGROUND

The ricefield eel Monopterus albus undergoes a natural sex change from female to male during its life cycle, and previous studies have shown the potential mechanisms of this transition at the transcriptional and protein levels. However, the changes in protein levels have not been fully explored, especially in the intersexual stage.

RESULTS

In the present study, the protein expression patterns in the gonadal tissues from five different periods, the ovary (OV), early intersexual stage gonad (IE), middle intersexual stage gonad (IM), late intersexual stage gonad (IL), and testis (TE), were determined by untargeted proteomics sequencing. A total of 5125 proteins and 394 differentially expressed proteins (DEPs) were detected in the gonadal tissues. Of the 394 DEPs, there were 136 between the OV and IE groups, 20 between the IM and IE groups, 179 between the IL and IM groups, and 59 between the TE and IL groups. Three candidate proteins, insulin-like growth factor 2 mRNA-binding protein 3 isoform X1 (Igf2bp3), triosephosphate isomerase (Tpi), and Cu-Zn superoxide dismutase isoform X1 [(Cu-Zn) Sod1], were validated by western blotting to verify the reliability of the data. Furthermore, metal metabolite-related proteins were enriched in the IL vs. IM groups and TE vs. IL groups, which had close relationships with sex change, including Cu2+-, Ca2+-, Zn2+- and Fe2+/Fe3+-related proteins. Analysis of the combined transcriptome data revealed consistent protein/mRNA expression trends for two metal metabolite-related proteins/genes [LOC109953912 and calcium Binding Protein 39 Like (cab39l)]. Notably, we detected significantly higher levels of Cu2+ during the sex change process, suggesting that Cu2+ is a male-related metal metabolite that may have an important function in male reproductive development.

CONCLUSIONS

In summary, we analyzed the protein profiles of ricefield eel gonadal tissues in five sexual stages (OV, IE, IM, IL, and TE) and verified the plausibility of the data. After preforming the functional enrichment of metal metabolite-related DEPs, we detected the contents of the metal metabolites Zn2+, Cu2+, Ca2+, and Fe2+/Fe3+ at these five stages and screened for (Cu-Zn) Sod1 and Mmp-9 as possible key proteins in the sex reversal process.

Histopathological effects of long-term exposure to realistic concentrations of cadmium in the hepatopancreas of Sparus aurata juveniles

In recent decades, cadmium has emerged as an environmental stressor in aquatic ecosystems due to its persistence and toxicity. It can enter water bodies from various natural and anthropogenic sources and, once introduced into aquatic systems, can accumulate in sediments and biota, leading to bioaccumulation and biomagnification in the food chain. For this reason, the effects of cadmium on aquatic life remain an area of ongoing research and concern. In this paper, a multidisciplinary approach was used to assess the effects of long-term exposure to an environmental concentration on the hepatopancreas of farmed juveniles of sea bream, Sparus aurata. After determining metal uptake, metallothionein production was assessed to gain insight into the organism's defence response. The effects were also assessed by histological and ultrastructural analyses. The results indicate that cadmium accumulates in the hepatopancreas at significant concentrations, inducing structural and functional damage. Despite the parallel increase in metallothioneins, fibrosis, alterations in carbohydrate distribution and endocrine disruption were also observed. These effects would decrease animal fitness although it did not translate into high mortality or reduced growth. This could depend on the fact that the animals were farmed, protected from the pressure deriving from having to search for food or escape from predators. Not to be underestimated is the return to humans, as this species is edible. Understanding the behaviour of cadmium in aquatic systems, its effects at different trophic levels and the potential risks to human health from the consumption of contaminated seafood would therefore be essential for informed environmental management and policy decisions.

Mechanism of cadmium-induced nephrotoxicity

Heavy metals are found naturally in our environment and have many uses and applications in daily life. However, high concentrations of metals may be a result of pollution due to industrialization. In particular, cadmium (Cd), a white metal abundantly distributed in the terrestrial crust, is found in mines together with zinc, which accumulates after volcanic eruption or is found naturally in the sea and earth. High levels of Cd have been associated with disease. In the human body, Cd accumulates in two ways: via inhalation or consumption, mainly of plants or fish contaminated with high concentrations. Several international organizations have been working to establish the limit values of heavy metals in food, water, and the environment to avoid their toxic effects. Increased Cd levels may induce kidney, liver, or neurological diseases. Cd mainly accumulates in the kidney, causing renal disease in people exposed to moderate to high levels, which leads to the development of end-stage chronic kidney disease or death. The aim of this review is to provide an overview of Cd-induced nephrotoxicity, the mechanisms of Cd damage, and the current treatments used to reduce the toxic effects of Cd exposure.

MicroRNA-129-1-3p protects chicken granulosa cells from cadmium-induced apoptosis by down-regulating the MCU-mediated Ca2+ signaling pathway

Cadmium (Cd) is known as a female reproductive toxicant. Our previous study has shown that Cd can influence the proliferation and cell cycle of granulosa cells and induce apoptosis. MicroRNAs (miRNAs) play an important role in the regulation of Cd-induced granulosa cell damage in chickens. However, the mechanism remains unclear. In this study, we investigated the mechanisms by which microRNA-129-1-3p (miR-129-1-3p) regulates Cd-induced cytotoxicity in chicken granulosa cells. As anticipated, exposure to Cd resulted in the induction of oxidative stress in granulosa cells, accompanied by the downregulation of antioxidant molecules and/or enzymes of Nrf2, Mn-SOD, Cu-Zn SOD and CAT, and the upregulation of Keap1, GST, GSH-Px, GCLM, MDA, hydrogen peroxide and mitochondrial reactive oxygen species (mtROS). Further studies found that Cd exposure causes mitochondrial calcium ions (Ca2+) overload, provoking mitochondrial damage and apoptosis by upregulating IP3R, GRP75, VDAC1, MCU, CALM1, MFF, caspase 3, and caspase 9 gene and/or protein expressions and mitochondrial Ca2+ levels, while downregulating NCX1, NCLX and MFN2 gene and/or protein expressions and mitochondrial membrane potential (MMP). The Ca2+ chelator BAPTA-AM or the MCU inhibitor MCU-i4 significantly rescued Cd-induced mitochondrial dysfunction, thereby attenuating apoptosis. Additionally, a luciferase reported assay and western blot analysis confirmed that miR-129-1-3p directly target MCU. MiR-129-1-3p overexpression almost completely inhibited protein expression of MCU, increased the gene and protein expressions of NCLX and MFN2 downregulated by Cd, and attenuated mitochondrial Ca2+ overload, MMP depression and mitochondria damage induced by Cd. Moreover, the overexpression of miR-129-1-3p led to a reduction in mtROS and cell apoptosis levels, and a suppression of the gene and protein expressions of caspase 3 and caspase 9. As above, these results provided the evidence that IP3R-MCU signaling pathway activated by Cd plays a significant role in inducing mitochondrial Ca2+ overload, mitochondrial damage, and apoptosis. MiR-129-1-3p exerts a protective effect against Cd-induced granulosa cell apoptosis through the direct inhibition of MCU expression in the ovary of laying hens.

Spermidine suppresses oxidative stress and ferroptosis by Nrf2/HO-1/GPX4 and Akt/FHC/ACSL4 pathway to alleviate ovarian damage

AIMS

Oxidative stress is considered to be one of the culprits of ovarian dysfunction. Spermidine (SPD) is a natural aliphatic polyamine that is widely present in living organisms and has been shown to exert preventive effects on various ageing-related diseases. This study seeks to investigate the potential preventive and protective effects of SPD on ovarian oxidative damage.

MAIN METHODS

Ovarian oxidative stress model in C57BL/6 mice was established by 3-nitropropionic acid. Female mice were administrated 10 mg/kg or 15 mg/kg SPD. The estrous cycle, serum hormone levels and mating test were measured to evaluate ovarian function. Follicle counts and AMH levels to assess ovarian reserve. Masson's trichrome to assess ovarian fibrosis. TUNEL analysis to evaluate follicular granulosa cells (GCs) apoptosis. Oxidative stress and autophagy indicators (Nrf2, HO-1, GPX4, LC3B, P62) were measured in vivo and in vitro. RNA-sequencing was performed on SPD-treated GC to study the effects of SPD on Akt and FHC/ACSL4 signaling.

KEY FINDINGS

SPD supplementation improved ovarian endocrine function and reproductive capacity in oxidative stress mice. SPD regularized the estrous cycle and alleviated oxidative stress. Furthermore, SPD increased the ovarian reserve, reducing GC apoptosis by activating the Nrf2/HO-1/GPX4 pathway. RNA-sequencing showed that SPD induced 230 genes changes in porcine GC, which were mainly involved in oocyte meiosis, arginine biosynthesis and glutathione metabolism pathways. SPD attenuated H2O2-induced ferroptosis by regulating Akt/FHC/ACSL4 signaling.

SIGNIFICANCE

SPD alleviates oxidative stress and ferroptosis by regulating the Nrf2/HO-1/GPX4 and Akt/FHC/ACSL4 pathway, which may be a novel potential strategy to protect ovarian oxidative damage.

DNA damage resulting from human endocrine disrupting chemical exposure: Genotoxicity, detection and dietary phytochemical intervention

In recent years, exposure to endocrine disrupting chemicals (EDCs) has posed an increasing threat to human health. EDCs are major risk factors in the occurrence and development of many diseases. Continuous DNA damage triggers severe pathogenic consequences, such as cancer. Beyond their effects on the endocrine system, EDCs genotoxicity is also worthy of attention, owing to the high accessibility and bioavailability of EDCs. This review investigates and summarizes nearly a decade of DNA damage studies on EDC exposure, including DNA damage mechanisms, detection methods, population marker analysis, and the application of dietary phytochemicals. The aims of this review are (1) to systematically summarize the genotoxic effects of environmental EDCs (2) to comprehensively summarize cutting-edge measurement methods, thus providing analytical solutions for studies on EDC exposure; and (3) to highlight critical data on the detoxification and repair effects of dietary phytochemicals. Dietary phytochemicals decrease genotoxicity by playing a major role in the detoxification system, and show potential therapeutic effects on human diseases caused by EDC exposure. This review may support research on environmental toxicology and alternative chemo-prevention for human EDC exposure.

Association of blood cadmium and lead levels with self-reported reproductive lifespan and pregnancy loss: The national health and nutrition examination survey 1999-2018

Cadmium and lead are known to interfere with the endocrine function. Thus, hormonally regulated processes such as menarche, menopause and pregnancy are likely influenced by chronic exposure to these metals. In US post-menopausal women, who already completed their reproductive lifespan, we evaluated the association between blood cadmium and lead levels with self-reported reproductive lifespan and personal history of pregnancy loss. We selected 5317 post-menopausal women participating in the National Health and Nutrition Examination Survey (NHANES), 1999-2018. Blood cadmium and lead levels were measured by inductively coupled plasma mass spectrometry. Reproductive lifespan was defined as the number of years between self-reported age at menarche and menopause. Personal history of pregnancy loss was defined as number of self-reported pregnancy losses out of the self-reported number of pregnancies. The fully adjusted mean difference in reproductive lifespan (95% confidence interval [CI]) comparing the 80th to the 20th percentiles of blood cadmium and lead distributions was, respectively, 0.50 (0.10, 0.91) and 0.72 (0.41, 1.03) years. Ever smoker showed stronger association of blood lead with reproductive lifespan. For self-reported pregnancy loss, the corresponding fully adjusted relative prevalence (95% CI) was 1.10 (0.93, 1.31) for cadmium and 1.10 (1.00, 1.21) for lead, and remained similar after additional adjustment for reproductive lifespan. In never smokers, the relative prevalence was 1.07 (1.04, 1.11) and 1.16 (1.05, 1.28) for blood cadmium and lead, respectively. These findings suggest that blood cadmium and lead exposures increase reproductive lifespan and prevalence of pregnancy loss in the general population. Additional studies are needed to improve the understanding of mechanisms and prevention potential of metals-related pregnancy outcomes.

Toxic Effects of Cadmium on the Female Reproductive Organs a Review

Cadmium (Cd) is a common environmental pollutant present in soil and associated with many modern industrial processes. Cadmium may adversely influence the health of experimental animals and humans and exert significant effects on the reproductive tract morphology and physiology. During embryonic development, cadmium suppresses the normal growth and development of the ovaries, and in adults it disrupts the morphology and function of the ovaries and uterus. The exposure to cadmium has adverse effects on the oocyte meiotic maturation affecting the structure of ovarian tissue. The distribution of follicles and corpus luteum in the ovarian tissues has been shown to be disrupted, affecting the normal growth and development of the follicles. In the ovarian cortex, the number of follicles at different stages of maturation decreased, and the number of atretic follicles increased. In the medulla, oedema and ovarian haemorrhage and necrosis appears at higher doses. Granulosa cells exposed to cadmium exhibited morphological alterations. Oocyte development was inhibited and the amount of oocyte apoptosis was higher. Cadmium exposure also caused changes in the structure of the ovarian blood vessels with reduction in the vascular area. Cadmium effects included increased uterine weight, hyperplasia and hypertrophy of the endometrial lining. Exposure to cadmium had specific effects on gonadal steroidogenesis by suppressing steroid biosynthesis of the ovarian granulosa cells and luteal cells. Progesterone, follicle stimulating hormone, and luteinizing hormone decreased significantly after CdCl2 administration. Cadmium can suppress the female’s ovulation process and cause temporary infertility.