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

Fertility loss: negative effects of environmental toxicants on oogenesis

There has been a global decline in fertility rates, with ovulatory disorders emerging as the leading cause, contributing to a global lifetime infertility prevalence of 17.5%. Formation of the primordial follicle pool during early and further development of oocytes after puberty is crucial in determining female fertility and reproductive quality. However, the increasing exposure to environmental toxins (through occupational exposure and ubiquitous chemicals) in daily life is a growing concern; these toxins have been identified as significant risk factors for oogenesis in women. In light of this concern, this review aims to enhance our understanding of female reproductive system diseases and their implications. Specifically, we summarized and categorized the environmental toxins that can affect oogenesis. Here, we provide an overview of oogenesis, highlighting specific stages that may be susceptible to the influence of environmental toxins. Furthermore, we discuss the genetic and molecular mechanisms by which various environmental toxins, including metals, cigarette smoke, and agricultural and industrial toxins, affect female oogenesis. Raising awareness about the potential risks associated with toxin exposure is crucial. However, further research is needed to fully comprehend the mechanisms underlying these effects, including the identification of biomarkers to assess exposure levels and predict reproductive outcomes. By providing a comprehensive overview, this review aims to contribute to a better understanding of the impact of environmental toxins on female oogenesis and guide future research in this field.

Therapeutic effects of avocado (Persea americana Mill.) seed powder against reproductive toxicity induced by Mancozeb (herbicide) in female rabbits

Pesticides like Mancozeb are being increasingly indispensable in the control of crop pests. Unfortunately, they have been implicated in genotoxicity due to their ubiquity, toxicological properties, persistence and presence in the food chain. This study sought to evaluate the efficacy of powdered avocado seed on reproductive parameters in the management of oxidative stress in female rabbits caused by the herbicide Mancozeb. Twenty-eight female rabbits aged 7-8 months and weighing between 2780.4 g and 3143.7 g were randomly divided into four groups of seven rabbits each. Each group received for 90 consecutive days distilled water or Mancozeb associated or not with avocado seed powder orally as follows: T1: 10 ml distilled water; T2, T3 and T4: 100 mg/kg bw Mancozeb. This was followed by oral administration of 250, 500, and 0 mg/kg of avocado seed powder for T2, T3, and T4, respectively. Water and feed were distributed ad libitum. Collected data concerned growth, carcass and reproductive performances, hematological and biochemistry characteristics. Results demonstrated that pregnant and lactating female rabbits administered Mancozeb exhibited a significant decrease (P < 0.05) in food intake, body weight, and body weight gain. Female rabbits exposed to Mancozeb had a decrease in litter size and weight from birth to weaning, as well as in weaning body weight and weight increase, fertility and prolificacy rate, milk yield, and daily milk efficiency. However, administration of avocado seed powder reversed (P < 0.05) the trends in these parameters in a dose-dependent manner. The increase in relative weight of the kidney and liver, concentrations of urea, creatinine, alanine and aspartate aminotransferases, mean cell volume, white blood cells, and lymphocytes were all associated with increased Mancozeb rates (P < 0.05). On the contrary, administration of the Mancozeb caused decrease in hemoglobin (Hb), Red blood Cell (RBC) and protein content. Administration of avocado seed powder significantly (P < 0.05) ameliorated the Mancozeb effects on these parameters. Applying 500 mg/kg b.w Avocado seed powder may be suggested as an alternative therapy for reproductive defects induced by Mancozeb in female rabbits.

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.

Ameliorating Effects of Natural Antioxidant Compounds on Female Infertility: a Review

The prevalence of female infertility cases has been increasing at a frightening rate, affecting approximately 48 million women across the world. However, oxidative stress has been recognized as one of the main mediators of female infertility by causing various reproductive pathologies in females such as endometriosis, PCOS, preeclampsia, spontaneous abortion, and unexplained infertility. Nowadays, concerned women prefer dietary supplements with antioxidant properties over synthetic drugs as a natural way to lessen the oxidative stress and enhance their fertility. Therefore, the current review is an attempt to explore the efficacy of various natural antioxidant compounds including vitamins, carotenoids, and plant polyphenols and also of some medicinal plants in improving the fertility status of females. Our summarization of recent findings in the current article would pave the way toward the development of new possible antioxidant therapy to treat infertility in females. Natural antioxidant compounds found in fruits, vegetables, and other dietary sources, alone or in combination with other antioxidants, were found to be effective in ameliorating the oxidative stress-mediated infertility problems in both natural and assisted reproductive settings. Numerous medicinal plants showed promising results in averting the various reproductive disorders associated with female infertility, suggesting a plant-based herbal medicine to treat infertility. Although optimum levels of natural antioxidants have shown favorable results, however, their excessive intake may have adverse health impacts. Therefore, larger well-designed, dose-response studies in humans are further warranted to incorporate natural antioxidant compounds into the clinical management of female infertility.

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.