Persistent testicular structural and functional alterations after exposure of adult rats to atrazine

Exploring the endocrine-disrupting potential of atrazine for male reproduction: A systematic review and meta-analysis

Atrazine is an herbicide widely used on plantations worldwide. Experimental studies suggest that the herbicide impairs male reproductive function in mammals. This systematic review and meta-analysis aimed to evaluate the impact of atrazine exposure on the levels of hormones from the hypothalamic-pituitary-testicular axis using murine as the animal model. After an extensive literature search, we selected 25 articles for the systematic review. Bias analysis and methodological quality assessments were examined using the SYRCLE Risk of Bias tool. Moreover, 20 out of the 25 studies were eligible for performing a meta-analysis to evaluate the intensity of atrazine damage on the levels of intratesticular testosterone and serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, estradiol, and progesterone. The meta-analysis revealed that atrazine exposure decreased serum FSH, LH, and testosterone levels, besides increased serum estradiol and progesterone levels. Atrazine also caused a reduction in intratesticular testosterone levels. Exposure to atrazine in high concentrations (≥ 100 mg Kg-1) was the main cause of endocrine disruption, regardless of the exposure time. None of the studies have tested doses relevant to human health risk. Oxidative stress and inflammation are involved in atrazine toxicity, impairing the gonadotropin release by the pituitary, disturbing steroidogenesis, and affecting the male hormone regulatory system. We may conclude that hormone disturbances lead to a failure in testicular steroidogenesis, with possible implications for male reproductive function. The registration number on the Prospero platform is CRD42024495626.

Co-Administration of a Plantain-Based Diet and Quercetin Modulates Atrazine-Induced Testicular Dysfunction in Rats via Testicular Steroidogenesis and Redox-Inflammatory Processes

Plantain has been reported to enhance testicular function indices, however, the mechanism remains unknown. The present study investigated the action mechanisms of a plantain-based diet in the treatment of rat testicular dysfunction caused by exposure to atrazine (ATZ). The rats were grouped into 10 groups (5 rats each); control group, 50% plantain-based diet (50% PBD), 25% PBD, 12.5% PBD, quercetin (QUE), ATZ only, 50% PBD + ATZ, 25% PBD + ATZ, 12.5% PBD + ATZ, and QUE + ATZ for 21 days. Results revealed that ATZ treatments in rats lowered gonadal hormone levels and the semen quality (sperm concentration, motility, count, and viability), damaged testicular morphology and functions, and impaired redox-inflammatory balance as well as cholinergic and purinergic activities. However, treatment with PBD and QUE ameliorated the testicular toxicity induced by ATZ, although the treatment did not improve the rat semen quality. In addition, the ATZ + QUE and QUE groups showed mild to moderate atrophic degenerative changes, with reduced spermatogenic activity. Together, the results are evidence that 21 days of exposure to ATZ impaired testicular function. However, co-administration of atrazine and PBD improves rat gonadal hormones, redox state, inflammatory indices, cholinergic, and purinergic activities, as well as histoarchitecture of the testes.

Morroniside repairs atrazine-induced skin damage by ameliorating lipid metabolism disorders and inhibiting ferroptosis

Morroniside (MOR) has shown great potential in treating atrazine (ATZ)-induced skin damage. This study aims to elucidate MOR's mechanism of action in mitigating lipid metabolism disorders and inhibiting ferroptosis to repair ATZ-induced skin damage. Twenty C57BL/6 mice were divided into four groups: the control group, the ATZ group, the MOR-H group and the MOR-L group, each comprising five mice. Following a one-month intervention, mouse skin tissues were harvested for untargeted lipid metabolomics analysis. Subsequently, the samples were assessed for indices related to ferroptosis. Untargeted lipid metabolomics analysis showed 127 differential metabolites in the ATZ vs. Ctrl group. There were 57 differential metabolites in the MOR-L vs. ATZ group. 34 differential metabolites in the MOR-H vs. ATZ group. the most obvious lipid reversal occurred after MOR-L administration, which primarily involved phospholipids, ceramides, and sphingomyelins. The levels of GPX4, Ferritin, MDA, SOD and GSH-PX, ferroptosis-related indicators, and the levels of p21 and p53, apoptosis-related indicators, were most significantly regressed in the MOR-L group (all P < 0.05). MOR may delay cellular aging and correct skin damage by reversing ATZ-induced lipid metabolism disorders, inhibiting ferroptosis and excessive oxidative stress occurrence.

Acute effects of atrazine on the immunoexpressions of sertoli and germ cells molecular markers, cytokines, chemokines, and sex hormones levels in mice testes and epididymides

Atrazine is currently one of the most commonly used agrochemicals in the United States and elsewhere. Here, we studied the immunoexpression of molecular markers of mammalian testicular functions: androgen receptor (AR), promyelocytic leukemia zinc finger (PLZF), GDNF family receptor alpha-1 (GFRA1), VASA/DDX4 (DEAD-Box Helicase 4) as well as the levels of intratesticular and intra-epididymal estradiol (E2) and dihydrotestosterone (DHT), tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), interleukins (IL-1β and IL-6, IL-10) and testicular chemokines (CXCL-1, CCL-2 and CCL3) in BalB/c mice after a sub-acute gavage treatment with a gonado-toxin, atrazine (50 mg/kg body wt.) for three days. We found high numbers of AR immunopositive Sertoli cells and low numbers of GFRA1, PLZF and VASA/DDX4-positive germ cells in the seminiferous tubule regions of the testes. While TNF-α level in the testes fell and remained unchanged in the epididymides, IFN-γ levels in the testes remained constant but increased in the epididymides. E2 and DHT concentrations remained unaltered in the testes but were changed in the epididymides. There were no significant changes in the levels of interleukins in the testis and epididymis. Intratesticular chemokines were also not significantly altered, except for CCL-4, which was increased in the testis. Light microscopy of the epididymis showed detached epithelium and some detached cells in the lumen. It is concluded that atrazine changed the inflammatory status of the gonads and highlighted Sertoli and undifferentiated spermatogonia as important targets for atrazine's toxic effects in the testis of mice. Concerning the epididymis, atrazine altered the epididymal hormonal concentrations and promoted histopathological modifications in its parenchyma.

Influence of triazines and lipopolysaccharide coexposure on inflammatory response and histopathological changes in the testis and liver of BalB/c mice

Background

Triazines are environmental active chemicals that have been reported to alter the inflammatory status of the gonads. We tested the anti-inflammatory effect of the triazines (atrazine; ATZ, simazine; SMZ and cyanazine; CYZ) on the testis and compared it with the more classical liver model that has substantial populations of resident macrophages comparable to the testis.

Methods

BalB/c mice were treated with 25 mg/kg ATZ, SMZ and CYZ for 30 days and injected with lipopolysaccharide (0.5 mg/kg i.p.) 6 h before sacrifice. Myeloperoxidase activity and nitric oxide level in the testis and liver homogenates were determined by spectrophotometry whereas tumor necrosis factor-alpha and interleukin-6 concentrations were evaluated by immunoassay. Haematoxylin and eosin stained sections of the tissues were observed using a light microscope.

Results

Myeloperoxidase activity, nitric oxide, tumor necrosis factor-alpha, and interleukin-6 levels were decreased in the liver and testis of the triazines co-treated animals. SMZ has the most potent inhibitory effect and ATZ the least effect on inflammatory mediators in both tissues. Microscopic evaluation showed loss of inflammatory cells in the inter-tubular areas of the testis and few patchy masses of infiltrating inflammatory cells around the central vein of the liver.

Conclusion

Triazines inhibit the levels of inflammatory mediators in the testis and liver of mice. The anti-inflammatory effect of triazines in a lipopolysaccharide-induced inflammation model was established in this study.

Testosterone restores TM3 and TM4 cell viability, reduces reactive oxygen species generation, and protects against atrazine-induced stereological changes in rat testes

In this study, we performed the stereological examination of rat testes and evaluated the protective effect of testosterone against atrazine (ATZ) toxicity in TM3 Leydig and TM4 Sertoli cells. Testosterone intake in rats increased the volumetric density of the seminiferous tubules; tubular diameter; germinal epithelial height; number of spermatogonia, primary and secondary spermatocytes, round spermatids, Sertoli cells, and Leydig cells; and Johnsen scores compared with the values after ATZ treatment (p < 0.05). Furthermore, testosterone increased the viability of TM3 cells and reduced reactive oxygen species (ROS) generation in TM4 cells compared to the ATZ-treated group. In conclusion, exogenous testosterone intake maintains testicular morphometry and spermatogenesis in rats, and minimizes cell death and ROS generation in testicular cell lines exposed to ATZ. However, TM4 cells are more responsive to testosterone-mediated regulation of ROS generation induced by ATZ than TM3 cells.

Atrazine exposure caused oxidative stress in male rats and inhibited brain-pituitary-testicular functions

Exposure to the herbicide atrazine has been shown to have deleterious effects on human and animal reproduction. To determine whether atrazine influences the brain-pituitary-testicular axis directly or indirectly, the present study examined the toxic effects of atrazine on fertility potential by assessing gonadal hormones, testicular function indices, sperm quality, and oxido-inflammatory markers in rats. Twelve animals were grouped into two groups; control and atrazine. The control group received oral administration of olive oil (2 mL/kg), while the atrazine group received 120 mg/kg of atrazine. Treatments were daily and lasted for 7 days. Upon treatment cessation, rats were necropsied for biochemical and histopathological analyses. The biochemical function indices in the rat brain, testis, and epididymis decreased significantly in the atrazine group. Atrazine exposure led to decreases in gonadal hormonal concentrations, semen quality parameters, and testicular function indices compared with the control. Furthermore, there was a marked increase in oxidative stress and inflammatory markers as well as degeneration of the histo-architecture in atrazine-treated rats. Overall, atrazine exposure impaired sperm quality, led to increased inflammation and oxidative stress, and decreased the activity of the brain-pituitary-testicular axis via endocrine disruption.

Atrazine Toxicity: The Possible Role of Natural Products for Effective Treatment

There are various herbicides which were used in the agriculture industry. Atrazine (ATZ) is a chlorinated triazine herbicide that consists of a ring structure, known as the triazine ring, along with a chlorine atom and five nitrogen atoms. ATZ is a water-soluble herbicide, which makes it capable of easily infiltrating into majority of the aquatic ecosystems. There are reports of toxic effects of ATZ on different systems of the body but, unfortunately, majority of these scientific reports were documented in animals. The herbicide was reported to enter the body through various routes. The toxicity of the herbicide can cause deleterious effects on the respiratory, reproductive, endocrine, central nervous system, gastrointestinal, and urinary systems of the human body. Alarmingly, few studies in industrial workers showed ATZ exposure leading to cancer. We embarked on the present review to discuss the mechanism of action of ATZ toxicity for which there is no specific antidote or drug. Evidence-based published literature on the effective use of natural products such as lycopene, curcumin, Panax ginseng, Spirulina platensis, Fucoidans, vitamin C, soyabeans, quercetin, L-carnitine, Telfairia occidentalis, vitamin E, Garcinia kola, melatonin, selenium, Isatis indigotica, polyphenols, Acacia nilotica, and Zingiber officinale were discussed in detail. In the absence of any particular allopathic drug, the present review may open the doors for future drug design involving the natural products and their active compounds.

Impact of Chronic Multi-Generational Exposure to an Environmentally Relevant Atrazine Concentration on Testicular Development and Function in Mice

A common herbicide, atrazine, is associated with poor health. Atrazine acts as an endocrine disruptor at supra-environmental levels. Little research, however, has been conducted regarding chronic exposure to environmental atrazine concentrations across generations. This study utilized comprehensive endpoint measures to investigate the effects of chronic exposure to a conservative atrazine concentration (0.02 ng/mL), measured in Australian waterways, on male mice fertility across two generations. Mice were exposed through the maternal line, from the pre-conception period and through the F1 and F2 generations until three or six months of age. Atrazine did not impact sperm function, testicular morphology nor germ cell parameters but did alter the expression of steroidogenic genes in the F1, down-regulating the expression of Cyp17a1 (Cytochrome P450 family 17, subfamily A member 1; p = 0.0008) and Ddx4 (DEAD-box helicase 4; p = 0.007), and up-regulating the expression of Star (Steroidogenic acute regulatory protein; p = 0.017). In the F2, atrazine induced up-regulation in the expression of Star (p = 0.016). The current study demonstrates that chronic exposure to an environmentally relevant atrazine concentration perturbs testicular steroid-associated gene expression that varies across generations. Future studies through the paternal and combined parental lineages should be undertaken to further elucidate the multigenerational effects of atrazine on male fertility.

Concentration of current-use pesticides in frogs from the Pampa region and correlation of a mixture toxicity index with biological effects

Contamination with current-use pesticides is frequently mentioned as a key factor in global amphibian declines although a limited number of studies have examined the mixture of pesticides accumulated by free-living frogs. This study examined the presence of 46 different pesticide residues in the muscle and kidney tissues of two frog species living in close association with row crops in the Pampa region of Argentina: The terrestrial Leptodactylus latinasus and the semi-aquatic Leptodactylus latrans. A total of 20 different pesticides were identified in frog tissues; chlorpyrifos-methyl, pirimiphos-methyl and acetochlor being the most frequently detected molecules. Overall, one or more pesticide residues (up to 12 in a single frog) were detected in 40-57 % of L. latrans. L. latinasus was found to present more pesticide detections than L. latrans. Interestingly, frog sampled in a natural reserve where no pesticides are applied presented an equivalent frequency of detections as frogs living near a crop. In L. latrans, the calculation of a pesticide toxicity index (PTI) permitted to highlight the existence of a strong positive correlation between PTI and liver GSH contents of females whereas, in males, PTI was negatively correlated with the perimeter of testicular seminiferous tubules. Males also presented near significant negative correlations between PTI and both body condition and the scaled fat index. These results indicate that frogs inhabiting agricultural regions are exposed to a complex and diffuse contamination by pesticide mixtures which is likely responsible for a number of biological effects that may be relevant at the population level.

Evaluation of the oestrogenic potential of oestrone and bisphenol-A on the reproduction of Astyanax bimaculatus males after subacute exposure

In the last decades, oestrogenic compounds have often been reported in environmentally relevant concentrations in aquatic environments around the world. Most laboratory studies of oestrogens try to understand the effects of a single contaminant, but in natural environments, the effects may be quite different due to interactions with other compounds. The present study aimed to compare the action of oestrone (E1) and bisphenol-A (BPA), acting singularly and in combination, on the spermatogenesis of Astyanax bimaculatus. After exposure to 100 ng/L of E1, BPA and a mixture of the two for 15 days, our results showed that E1 and the E1 + BPA mixture significantly altered the number of spermatogenic cells. BPA presented high cytotoxicity when compared to other treatments. Analysis of the two oestrogenic compounds suggests that the E1 + BPA mixture has no additive or synergistic effects. Together, the results of the present study indicate that endocrine-disrupting chemicals (EDCs) analysed alone may behave differently than when administered with other substances.

Atrazine impairs testicular function in BalB/c mice by affecting Leydig cells

Several studies have reported the effects of atrazine on the gonads of many experimental models. However, the short-term effects of in vivo exposure to atrazine on the testes of mice are not well clarified. Here we reported that adult BalB/c mice exposed to atrazine (50 mg kg^-1 body weight) by gavage for three consecutive days have reduced numbers of 3β-hydroxysteroid dehydrogenase positive Leydig cells (LCs), associated with increased in situ cell death fluorescence and caspase-3 immuno-expression in the testes. Consequently, immunostaining for cell cycle gene regulators showed increased expressions of p45, accompanied with increased expressions of cyclin D2 and E2. Histological observations of the gonads showed reduced number of germ cells in particular areas, sloughed seminiferous epithelium, presence of giant apoptotic cells close to the seminiferous tubule lumen and in the epididymal lumen along with low numbers of Leydig cells in the testicular interstitial areas. Similarly, LCs isolated from the testes of BalB/c mice that were exposed to atrazine (0.5, 25, 50 mg kg^-1 body weight) in the same manner as in the first experiment presented dose-dependent increased caspase-3 activity, decreased cell viability, intratesticular and serum testosterone concentrations and LCs testosterone secretion. In summary, atrazine appears to directly decrease the number of testosterone secreting LCs in mice through apoptosis.

Mechanisms of action of agrochemicals acting as endocrine disrupting chemicals

Agrochemicals represent a significant class of endocrine disrupting chemicals that humans and animals around the world are exposed to constantly. Agrochemicals can act as endocrine disrupting chemicals through a variety of mechanisms. Recent studies have shown that several mechanisms of action involve the ability of agrochemicals to mimic the interaction of endogenous hormones with nuclear receptors such as estrogen receptors, androgen receptors, peroxisome proliferator activated receptors, the aryl hydrocarbon receptor, and thyroid hormone receptors. Further, studies indicate that agrochemicals can exert toxicity through non-nuclear receptor-mediated mechanisms of action. Such non-genomic mechanisms of action include interference with peptide, steroid, or amino acid hormone response, synthesis and degradation as well as epigenetic changes (DNA methylation and histone modifications). This review summarizes the major mechanisms of action by which agrochemicals target the endocrine system.

Environmental exposure to oestrogenic endocrine disruptors mixtures reflecting on gonadal sex steroids and gametogenesis of the neotropical fishAstyanax rivularis

Discharge of municipal wastewater promotes the entry of diverse oestrogenic compounds into the water bodies. This complex mixture of substances interferes in the steroidogenic pathway, being able to promote severe reproductive impairment in freshwater fish populations. The purpose of the present study was to evaluate the effects of oestrogenic endocrine disruptors (EDCs) mixture on gonadal sex steroids (testosterone, T; 11-ketotestosterone, 11-KT; 17β-oestradiol, E2; 17-hydroxyprogesterone, 17-OHP) in the peak of the reproductive season of Astyanax rivularis, correlating the results obtained with the proportion of germ cells and gonadal histopathology. Three sampling sites were chosen to conduct the study, one reference site (S1), without contamination by municipal wastewater and two sites (S2 and S3) receiving discharge of municipal wastewater. Males of A. rivularis presented higher concentrations of E2, lower androgens (T and 11-KT) in gonads when compared to males from site S1. Concentrations of 17-OHP did not present significant difference among sites. In sites S2 and S3, the proportion of early spermatocytes, spermatids and Leydig cells increased while spermatozoa decreased compared to fish from S1. The following gonadal histopathologies were detected in the male fishes: intersex gonads (28% in S3) and testicular degeneration with germinal epithelium exhibiting agglutinated germ cells masses and empty cysts (57% in S2 and 71% in S3). In females, concentrations of T, E2 and 17-OHP did not present significant difference among the sites, however higher 11-KT concentrations were detected in females from sites S2 and S3. A lower proportion of perinucleolar follicles and a higher incidence of vitellogenic follicles, besides, aged oocytes and the presence of eosinophilic proteinaceous fluid in the interstitial compartment were also found in females from impacted sites. These results indicate that the urbanization and consequent release of municipal wastewater containing oestrogenic compounds in the headwater creeks are altering the levels of sex hormones and gametogenesis of A. rivularis. Further studies should be performed to determine whether oestrogenic endocrine disrupters are disrupting the reproduction of A. rivularis.

Stage-specific testicular protein levels of the oestrogen receptors (ERα and ERβ) and Cyp19 and association with oestrogenic contamination in the lambari Astyanax rivularis (Pisces: Characidae)

Oestrogens participate in various biological processes such as oogenesis, vitellogenesis and testicular development, but studies regarding the distribution and protein levels of oestrogen receptors (ERα and ERβ) and aromatase (Cyp19) in testis are rarely investigated in fish species. The aim of the present study was to analyse the expression pattern of ERα, ERβ and Cyp19 in testis of Astyanax rivularis and, in addition, to verify if oestrogenic contamination interferes in the expression levels of these proteins. Quarterly, field samplings were carried out during a reproductive cycle in a stream of the Upper Velhas River with a good conservation status (site S1). In the gonadal maturation peak (June), when ripe stage was most abundant, fish collection was made in three streams: S1, reference site, and S2 and S3, sites contaminated by untreated sewage. The results of immunohistochemistry demonstrated labelling of Cyp19 in Leydig cells and acidophilic granulocytes, but spermatogonia, Sertoli cells, spermatids and spermatozoa were also labelled. ERα was more widely distributed than ERβ being found in all developmental germ cell phases. On the other hand, ERβ was found only in spermatogonia and spermatocytes. During testicular maturation, ELISA levels for Cyp19, ERα and ERβ followed the gonadosomatic index (GSI) with significant higher values in the ripe stage. Regarding to endocrine disruption, the males exposed to domestic sewage presented significant higher expression of Cyp19 and ERα when compared to the non-exposed fish. Together, our results demonstrate expression patterns of Cyp19, ERα and ERβ in the testis of A. rivularis. In addition, we indicate ERα and Cyp19 as sensitive biomarkers for monitoring of oestrogenic contamination in freshwater environments.

Atrazine affects the morphophysiology, tissue homeostasis and aromatase expression in the efferent ductules of adult rats with mild alterations in the ventral prostate

The widely used herbicide atrazine is a potent endocrine disruptor known to cause increased aromatase expression and transient increase in testicular weight followed by remarkable testis atrophy. However, whether the effects of atrazine on the testes are primary or secondary to dysfunctions in other components of male reproductive tract remains unknown. Given the high sensitivity of the efferent ductules to estrogen imbalance and the similarity to alterations previously described for other disruptors of these ductules function, and the testicular alterations observed after atrazine exposure, we hypothesized that the efferent ductules could be a target for atrazine. Herein we characterized the efferent ductules and the ventral prostate of adult Wistar rats treated with 200 mg/kg/day of atrazine for 7, 15, and 40 days. Additionally, we evaluated if the effects of atrazine in these organs could be reduced after discontinuation of the treatment. Atrazine exposure resulted in mild effects on the ventral prostate, but remarkable alterations on the efferent ductules, including luminal dilation, reduced epithelial height, and disruption of the epithelial homeostasis, which coincides with increased aromatase expression. Together with our previous data, these results suggest that at least part of the testicular effects of atrazine may be secondary to the alterations in the efferent ductules.

Basal Cells Show Increased Expression of Aromatase and Estrogen Receptor α in Prostate Epithelial Lesions of Male Aging Rats

Besides androgens, estrogen signaling plays a key role in normal development and pathologies of the prostate. Irreversible synthesis of estrogens from androgens is catalyzed by aromatase. Interestingly, animals lacking aromatase do not develop cancer or prostatitis, whereas those with overexpression of aromatase and, consequently, high estrogen levels develop prostatitis and squamous metaplasia via estrogen receptor 1 (ERα). Even with this evidence, the aromatase expression in the prostate is controversial. Moreover, little is known about the occurrence of age-dependent variation of aromatase and its association with histopathological changes commonly found in advanced age, a knowledge gap that is addressed herein. For this purpose, the immunoexpression of aromatase was evaluated in the prostatic complex of young adult to senile Wistar rats. ERα was also investigated, to extend our understanding of estrogen responsiveness in the prostate. Moderate cytoplasmic immunoreactivity for aromatase was detected in the glandular epithelium. Eventually, some basal cells showed intense staining for aromatase. The expression pattern for aromatase appeared similar in the normal epithelium when young and senile rats were compared; this result was corroborated by Western blotting. Conversely, in senile rats, there was an increase in the frequency of basal cells intensely stained for aromatase, which appeared concentrated in areas of intraepithelial proliferation and prostatitis. These punctual areas also presented increased ERα positivity. Together, these findings suggest a plausible source for hormonal imbalance favoring estrogen production, which, by acting through ERα, may favor the development of prostatic lesions commonly found in advanced age.