Precision of in Vivo Pesticide Toxicology Research Can Be Promoted by Mass Spectrometry Imaging Technology

Pesticides are crucial for agricultural production, but their excessive use has become a significant pollution source, leading to increased pesticide residues in the environment and food and posing a threat to human health. In vivo pesticide toxicology research aims to protect humans with detection technology playing a key role. Spatial information plays a crucial role in in vivo pesticide toxicity research. However, current technologies cannot simultaneously analyze the content and spatial information on pesticides in vivo. Mass spectrometry imaging (MSI) technology can address this limitation by simultaneously analyzing the content and spatial distribution of chemicals in vivo with high sensitivity and efficiency, aiding in the discovery of toxic biomarkers and mechanisms. Nevertheless, the limited application of MSI in vivo pesticide toxicology research hinders the accuracy of such research. Therefore, MSI should be promoted to enhance the accuracy of in vivo pesticide toxicology research.

Reproductive hormones, organophosphate esters and semen quality: Exploring associations and mediation effects among men from an infertility clinic

Accumulating evidence indicates that organophosphate esters (OPEs) exposure may affect semen quality. As a crucial factor in male reproduction, reproductive hormones might be linked organophosphate esters (OPEs) exposure and semen quality. This study aimed to explore the mediating role of reproductive hormones on the association between OPEs exposure and semen quality. Five serum reproductive hormones, semen quality, and 16 urinary OPE metabolites were measured among 491 reproductive-aged men from a reproductive center. The associations of urinary OPE metabolites with reproductive hormones and semen quality were assessed using multivariable linear regression models, and the mediating role of reproductive hormones was evaluated by mediation analyses. We found that follicle stimulating hormone (FSH) was positively associated with diphenyl phosphate (DPHP) that in turn was negatively associated with sperm total count. In addition, inverse associations were exhibited between serum FSH and sperm concentration, sperm total count, total motility, and progressive motility (all Ptrend <0.05). Mediation analysis further showed that FSH mediated 13.7% of the inverse association of DPHP and sperm total count. Although further investigations are required, our results suggest that FSH was an intermediate mechanism in the associations between OPEs exposure and impaired semen quality.

Adult Organophosphate and Carbamate Insecticide Exposure and Sperm Concentration: A Systematic Review and Meta-Analysis of the Epidemiological Evidence

BACKGROUND

Evidence of the negative impacts of contemporary use insecticides on sperm concentration has increased over the last few decades; however, meta-analyses on this topic are rare.

OBJECTIVES

This investigation assessed the qualitative and quantitative strength of epidemiological evidence regarding adult exposure to two classes of contemporary use insecticides-organophosphates (OPs) and N -methyl carbamates (NMCs)-and sperm concentration using robust and reproducible systematic review and meta-analysis methods.

METHODS

Three scientific databases (PubMed, Scopus, and Web of Science), two U.S. government databases (NIOSHTIC-2 and Science.gov), and five nongovernmental organization websites were searched for relevant primary epidemiological studies published in any language through 11 August 2022. Risk of bias and strength of evidence were evaluated according to Navigation Guide systematic review methodology. Bias-adjusted standardized mean difference effect sizes were calculated and pooled using a three-level, multivariate random-effect meta-analysis model with cluster-robust variance estimation.

RESULTS

Across 20 studies, 21 study populations, 42 effect sizes, and 1,774 adult men, the pooled bias-adjusted standardized mean difference in sperm concentration between adult men more- and less-exposed to OP and NMC insecticides was - 0.30 (95% CI: - 0.49 , - 0.10 ; P Satt < 0.01 ). Sensitivity and subgroup analyses explored statistical heterogeneity and validated the model robustness. Although the pooled effect estimate was modified by risk of bias, insecticide class, exposure setting, and recruitment setting, it remained negative in direction across all meta-analyses. The body of evidence was rated to be of moderate quality, with sufficient evidence of an association between higher adult OP and NMC insecticide exposure and lower sperm concentration.

DISCUSSION

This comprehensive investigation found sufficient evidence of an association between higher OP and NMC insecticide exposure and lower sperm concentration in adults. Although additional cohort studies can be beneficial to fill data gaps, the strength of evidence warrants reducing exposure to OP and NMC insecticides now to prevent continued male reproductive harm. https://doi.org/10.1289/EHP12678.

A review of the endocrine disrupting effects of micro and nano plastic and their associated chemicals in mammals

Over the years, the vaste expansion of plastic manufacturing has dramatically increased the environmental impact of microplastics [MPs] and nanoplastics [NPs], making them a threat to marine and terrestrial biota because they contain endocrine disrupting chemicals [EDCs] and other harmful compounds. MPs and NPs have deleteriouse impacts on mammalian endocrine components such as hypothalamus, pituitary, thyroid, adrenal, testes, and ovaries. MPs and NPs absorb and act as a transport medium for harmful chemicals such as bisphenols, phthalates, polybrominated diphenyl ether, polychlorinated biphenyl ether, organotin, perfluorinated compounds, dioxins, polycyclic aromatic hydrocarbons, organic contaminants, and heavy metals, which are commonly used as additives in plastic production. As the EDCs are not covalently bonded to plastics, they can easily leach into milk, water, and other liquids affecting the endocrine system of mammals upon exposure. The toxicity induced by MPs and NPs is size-dependent, as smaller particles have better absorption capacity and larger surface area, releasing more EDC and toxic chemicals. Various EDCs contained or carried by MPs and NPs share structural similarities with specific hormone receptors; hence they interfere with normal hormone receptors, altering the hormonal action of the endocrine glands. This review demonstrates size-dependent MPs' bioaccumulation, distribution, and translocation with potential hazards to the endocrine gland. We reviewed that MPs and NPs disrupt hypothalamic-pituitary axes, including the hypothalamic-pituitary-thyroid/adrenal/testicular/ovarian axis leading to oxidative stress, reproductive toxicity, neurotoxicity, cytotoxicity, developmental abnormalities, decreased sperm quality, and immunotoxicity. The direct consequences of MPs and NPs on the thyroid, testis, and ovaries are documented. Still, studies need to be carried out to identify the direct effects of MPs and NPs on the hypothalamus, pituitary, and adrenal glands.

Testicular deficiency associated with exposure to cypermethrin, imidacloprid, and chlorpyrifos in adult rats

The testicular deficiency associated with exposure to three widely used insecticides in Egyptian agriculture was evaluated. Animals were orally treated with sub-lethal dose (1/50 of the oral LD₅₀) of cypermethrin (CYP), imidacloprid (IMC), and chlorpyrifos (CPF) at 5, 9 and 1.9 mg/kg/day, respectively, five times a week for one month. The CYP, IMC, and CPF exposure resulted in a significant decline in animal body weight, sperm count, motility, normality, and viability with increased head and tail deformities. Significant reduction in serum testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), testis superoxide dismutase (SOD), and reduced glutathione (GSH) levels. In contrast, catalase (CAT), lipid peroxidation (LPO), and protein carbonyl content (PCC) levels were significantly stimulated. Jointly, obtained results were confirmed by microscopic examination of testis sections. The present data concluded that the CYP, IMC, and CPF have a public health impact and violently interferes with male rat reproductive system.

Antouka Super® induced oxidative stress and reproductive toxicity in male Japanese quail (Coturnix coturnix japonica)

Background

Antouka Super^® (AS), a combination of insecticide (Pirimiphos-methyl 16% and Permethrin 3%), is one of the most widely used pesticides in agriculture, public health, home and garden, with high potential for human and animal exposure.

Objective

The present study was undertaken to evaluate the effect of AS on the serum testosterone, oxidative stress biomarkers, testis histology and fertility of male Japanese quail.

Methods

Thirty-two (32) male Japanese quails twenty-eight (28) days were randomly divided into four groups: C0 (control), T1, T2 and T3, exposed daily (gavage) to 0, 37.5, 56.25 and 75 mg of AS/kg body weight (b.w), respectively, for 49 consecutive days and were analysed for fertility. Control and experimental male quails were cohabited, for two days, with untreated female quails and sperm positive female quail were analysed for paternal-mediated toxicity. After completion of fertility studies quails were sacrificed and analysed for reproductive endpoints.

Results

There was a dose dependent decrease of the relative weight of testis, epididymis and vas deferens. Additionally, testis total proteins and serum testosterone levels were decreased in AS treated quails (p < 0.05). A decrease of sperm motility, viability and concentration per vas deferens, and an increase of sperm anomalies were recorded in AS exposed quails with respect to the controls. The embryonic and post-embryonic mortality rate were significantly (p < 0.05) higher in group T3 (25.00 ± 3.40% and 31.66 ± 10.22% respectively) than in control group (6.25 ± 3.98% and 9.54 ± 3.72% respectively). The superoxide dismutase (SOD), total peroxidase (POD) and catalase activity (CAT) were significantly (p < 0.05) lower treated than control quails, while the level of malondialdehyde (MDA) was significantly (p < 0.05) higher in groups T1, T2 and T3 (13.00 ± 0.96, 23.50 ± 1.35 and 29.08 ± 1.58 nmol/mg tissues respectively) compared to the control one (9.32 ± 0.67nmol/mg tissues). Histopathological examination of the testes of AS treated quails revealed testicular lesions characterized by moderate to severe degenerative changes of seminiferous tubules, incomplete spermatogenesis and depletion in the germ layers of seminiferous tubules in which immature spermatozoa were hardly seen.

Conclusion

From the above study, it can be inferred that AS (56.25 and 75) mg/kg b.w decrease body and relative organ weights and induces testicular lesions. Also, AS increases the level of MDA while it reduces the levels of enzymatic antioxidant biomarkers, serum testosterone and reproductive indices of intoxicated quails and their offspring. However, further work is needed to establish the genetic toxicology and immunohistochemistry of caspase-3 and claudin-1.

Influence of environmental factors on biodegradation of quinalphos by Bacillus thuringiensis

BACKGROUND

The extensive and intensive uses of organophosphorus insecticide-quinalphos in agriculture, pose a health hazard to animals, humans, and environment because of its persistence in the soil and crops. However, there is no much information available on the biodegradation of quinalphos by the soil micro-organisms, which play a significant role in detoxifying pesticides in the environment; so research is initiated in biodegradation of quinalphos.

RESULTS

A soil bacterium strain, capable of utilizing quinalphos as its sole source of carbon and energy, was isolated from soil via the enrichment method on minimal salts medium (MSM). On the basis of morphological, biochemical and 16S rRNA gene sequence analysis, the bacterium was identified as to be Bacillus thuringiensis. Bacillus thuringiensis grew on quinalphos with a generation time of 28.38 min or 0.473 h in logarithmic phase. Maximum degradation of quinalphos was observed with an inoculum of 1.0 OD, an optimum pH (6.5-7.5), and an optimum temperature of 35-37 °C. Among the additional carbon and nitrogen sources, the carbon source-sodium acetate and nitrogen source-a yeast extract marginally improved the rate of degradation of quinalphos.

CONCLUSIONS

Display of degradation of quinalphos by B. thuringiensis in liquid culture in the present study indicates the potential of the culture for decontamination of quinalphos in polluted environment sites.

Melamine and/or formaldehyde exposures affect steroidogenesis via alteration of StAR protein and testosterone synthetic enzyme expression in male mice

The reproductive effects of melamine and formaldehyde, either alone or in combination, on mature male Swiss mice were investigated. The animals were orally administered melamine (50mg/kg/day), formaldehyde (25mg/kg/day), a mixture of melamine and formaldehyde, or a vehicle control for 65 consecutive days. As a result, the deterioration of sperm characteristics and inhibition of testicular enzyme activity were observed in the melamine- and formaldehyde-exposed groups. In addition, testosterone and luteinizing hormone levels were significantly reduced in the melamine but not in the formaldehyde-exposed group, which correlated with down-regulation of transcription levels of steroidogenic-related genes. Histopathologically, both compounds caused lesions in the testes. However, the co-exposure reduced the induced alterations in spermatogenesis, steroidogenesis, and testicular architecture that were obviously observed in the melamine-exposed group. Consequently, we demonstrated that melamine exhibited more pronounced reproductive impact in comparison with formaldehyde. In addition, formaldehyde was able to substantially temper the melamine -induced reproductive toxic effect.

A comprehensive review of pesticides and the immune dysregulation: mechanisms, evidence and consequences

Nowadays, in many communities, there is a growing concern about possible adverse effects of pesticides on human health. Reports indicate that during environmental or occupational exposure, pesticides can exert some intense adverse effects on human health through transient or permanent alteration of the immune system. There is evidence on the relation between pesticide-induced immune alteration and prevalence of diseases associated with alterations of the immune response. In the present study, direct immunotoxicity, endocrine disruption and antigenicity have been introduced as the main mechanisms working with pesticides-induced immune dysregulation. Moreover, the evidence on the relationship between pesticide exposure, dysregulation of the immune system and predisposition to different types of psychiatric disorders, cancers, allergies, autoimmune and infectious diseases are criticized.

Dialkyl phosphate urinary metabolites and chromosomal abnormalities in human sperm

BACKGROUND

The past decade has seen numerous human health studies seeking to characterize the impacts of environmental exposures, such as organophosphate (OP) insecticides, on male reproduction. Despite an extensive literature on OP toxicology, many hormone-mediated effects on the testes are not well understood.

OBJECTIVES

This study investigated environmental exposures to OPs and their association with the frequency of sperm chromosomal abnormalities (i.e., disomy) among adult men.

METHODS

Men (n=159) from a study assessing the impact of environmental exposures on male reproductive health were included in this investigation. Multi-probe fluorescence in situ hybridization (FISH) for chromosomes X, Y, and 18 was used to determine XX18, YY18, XY18 and total disomy in sperm nuclei. Urine was analyzed using gas chromatography coupled with mass spectrometry for concentrations of dialkyl phosphate (DAP) metabolites of OPs [dimethylphosphate (DMP); dimethylthiophosphate (DMTP); dimethyldithiophosphate (DMDTP); diethylphosphate (DEP); diethylthiophosphate (DETP); and diethyldithiophosphate (DEDTP)]. Poisson regression was used to model the association between OP exposures and disomy measures. Incidence rate ratios (IRRs) were calculated for each disomy type by exposure quartiles for most metabolites, controlling for age, race, BMI, smoking, specific gravity, total sperm concentration, motility, and morphology.

RESULTS

A significant positive trend was seen for increasing IRRs by exposure quartiles of DMTP, DMDTP, DEP and DETP in XX18, YY18, XY18 and total disomy. A significant inverse association was observed between DMP and total disomy. Findings for total sum of DAP metabolites concealed individual associations as those results differed from the patterns observed for each individual metabolite. Dose-response relationships appeared nonmonotonic, with most of the increase in disomy rates occurring between the second and third exposure quartiles and without additional increases between the third and fourth exposure quartiles.

CONCLUSIONS

This is the first epidemiologic study of this size to examine the relationship between environmental OP exposures and human sperm disomy outcomes. Our findings suggest that increased disomy rates were associated with specific DAP metabolites, suggesting that the impacts of OPs on testis function need further characterization in epidemiologic studies.

Quercetin mitigates fenitrothion-induced testicular toxicity in rats

Fenitrothion (FNT) is a widely used organophosphorus pesticide in agriculture. Quercetin (QR), a plant-derived flavonoid, has a free radical scavenging property. This study investigated the protective effect of QR on FNT-induced testicular toxicity in rats. Twenty-four male rats were divided into four groups. Group I (control) received normal saline. Group II was administered QR at the dose of 50 mg kg(-1) b.wt. Group III was orally administered FNT (20 mg kg(-1) b.wt). Group IV was gavaged FNT and QR together at the same doses. All administrations were performed daily by gavage and maintained for 70 days. Sperm parameters and histopathological changes in testes were investigated. Serum testosterone and luteinising hormone were estimated using radioimmunoassay kits. In testes, expressions of steroidogenic genes (3β-hydroxysteroid dehydrogenase type 6, 17 β-hydroxysteroid dehydrogenase type 3 and steroidogenic factor-1) and oxidative stress genes (catalase and superoxide dismutase) were determined using real-time PCR. FNT administration caused significant decreases in sperm count, motility and hormonal levels, a significant increase in abnormal sperm morphology and a significant down-regulation of steroidogenic and antioxidant genes in the testis. However, QR administration ameliorated FNT-induced toxic effects. Our results concluded that QR effectively mitigated testicular damage induced by FNT in rats.

Associations between urinary organophosphate pesticide metabolite levels and reproductive parameters in men from an infertility clinic

Organophosphate (OP) pesticides are compounds used for pest control at home or in agriculture activities. Almost all OP pesticides are metabolized to at least one of six possible dialkylphosphates (DAPs). Despite wide use, their potential effects on human reproductive health have not yet been fully characterized. The aim of this study was to evaluate the associations between urinary concentrations of six DAP metabolites and reproductive parameters in men. All men were attended an infertility clinic and provided urine, serum and semen samples on the same day. Six DAP metabolites were measured in urine (dimethylphosphate [DMP], dimethylthiophosphate [DMTP], dimethyldithiophosphate [DMDTP], diethylphosphate [DEP], diethylthiophosphate [DETP], and diethyldithiophosphate [DEDTP]). Sperm quality was assessed by measuring volume, concentration, total sperm count (TSC), motility and morphology, and serum samples were analyzed for reproductive hormones, including follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, prolactin and estradiol. Pearson correlations were used for unadjusted analyses, and multiple linear regression analysis was performed controlling for appropriate covariates. All men presented detectable concentrations of at least one urinary OP metabolite. After adjustment by important covariates, there was a significant positive association between DEDTP concentrations and LH [(β)=11.4; 95% CI 0.81-22.1] as well as FSH levels [(β)=3.2; 95% CI 0.08-6.2]. Sperm concentration and TSC were both significantly inversely associated with DMP, DMDP, DMDTP and ∑DAP in multivariate analysis. Besides, there was a significant inverse association between percentage of motile sperm and DMTP, DMDTP and DEP metabolite concentrations. Our results suggest that exposure to OP pesticides may be associated with decreased sperm counts and motility and altered reproductive hormone levels in male partners of couples seeking for infertility treatment. However, further studies are warranted to confirm and extent these findings.

Photocatalytic actions of the pesticide metabolite 2-hydroxyquinoxaline: destruction of antioxidant vitamins and biogenic amines – implications of organic redox cycling

Toxicity of the pesticide quinalphos may comprise secondary, delayed effects by its main metabolite 2-hydroxyquinoxaline (HQO). We demonstrate that HQO can destroy photocatalytically vitamins C and E, catecholamines, serotonin, melatonin, the melatonin metabolite AMK (N(1)-acetyl-5-methoxykynuramine), and unsubstituted and substituted anthranilic acids when exposed to visible light. In order to avoid HQO-independent ascorbate oxidation by light and to exclude actions by hydroxyl radicals, experiments on this vitamin were carried out in ethanolic solutions. Other substances tested (vitamin E, melatonin, anthranilic acids) were also photocatalytically destroyed by HQO in ethanol. After product analyses had indicated that HQO was not, or only poorly, degraded in the light, despite its catalytic action on other compounds, we followed directly the time course of HQO and ascorbate concentrations in ethanol. While ascorbate was largely destroyed, no change in HQO was demonstrable within 2 h of incubation. Destruction was not prevented by the singlet oxygen quencher DABCO. Obviously, HQO is capable of undergoing a process of organic redox cycling, perhaps via an intermediate quinoxaline-2-oxyl radical. Health problems from HQO intoxication may not only arise from the loss of valuable biomolecules, such as antioxidant vitamins and biogenic amines, but also from the formation of potentially toxic products. Dimerization and oligomerization are involved in several oxidation processes catalyzed by HQO, especially in the indoleamines, in dopamine, and presumably also in vitamin E. Melatonin oxidation by HQO did not only lead to the well-known - and usually protective - metabolite AFMK (N(1)-acetyl-N(2)-formyl-5-methoxykynuramine), but also to a high number of additional products, among them dimers and trimers. DABCO did not prevent melatonin destruction, but changed the spectrum of products. Serotonin was preferentially converted to a dimer, which can further oligomerize. Several indole dimers are known to be highly neurotoxic, as well as oxidation products formed from catecholamines via the adrenochrome/noradrenochrome pathway. Destruction of melatonin may cause deficiencies in circadian physiology, in immune functions and in antioxidative protection.

Pesticide exposure and endocrine dysfunction in the cotton crop agricultural workers of southern Punjab, Pakistan

This study evaluated pesticide effects on reproductive and thyroid hormones of cotton farmers of southern Punjab, Pakistan. A total of 88 cotton farmers (42 spray applicators and 46 cotton pickers) were randomly included with an equal number of age- and sex-matched controls. Sampling was done in high spraying and peak picking seasons. Serum levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, prolactin, thyroid-stimulating hormone (TSH), total triiodothyroxine (TT3), and free thyroxine (fT4) were carried out by enzymatic immunoassay. Plasma cholinesterase (PChE) levels were measured by Ellman's method. Serum FSH, LH, and testosterone levels were significantly high in spray applicators (P < .01).Serum FSH and testosterone levels were significantly raised in cotton pickers (P < .01). Serum prolactin was decreased significantly in both groups (P < .01).Serum fT4 was significantly reduced in cotton pickers (P < .01). Pesticide exposure is associated with thyroid and reproductive hormone levels disturbance.

Changes in male hormone profile after occupational organophosphate exposure. A longitudinal study

There is a growing concern about the endocrine effects of long-term, low-level exposure to organophosphate (OP) compounds. Studies on experimental animals have found that OP pesticides have an impact on the endocrine system and a few clinical and epidemiological studies have also shown that OPs may affect the male hormone profile, although results are inconsistent. We have evaluated the effect of exposure to OP pesticides, measured through urinary levels of six dialkylphosphate (DAP) metabolites, on male hormone profile in 136 floriculture workers from the State of Mexico and Morelos during two agricultural periods with different degree of pesticide exposure. Generalized estimated equations (GEE) models were developed and adjusted for several potential confounders, including PON1 enzyme activity, as a biomarker of susceptibility, and serum levels of p,p'-DDE, a metabolite of the pesticide DDT widely used in Mexico until 1999 for control of agricultural pests and malaria. Exposure of male floriculture workers to OP pesticides was associated with increased serum levels of follicle-stimulating hormone (FSH) and prolactin and with decreased serum testosterone and inhibin B levels. Among all DAPs tested, only DETP was inversely associated with luteinizing hormone (LH). Estradiol showed a marginally significant positive trend with DEP and DETP derivatives. In conclusion, OP pesticides may have an impact on the endocrine function because of their potential to modify the male hormone profile as a function of the type of pesticide used as well as the magnitude of exposure.

Quinalphos induced oxidative stress and histoarcheitectural alterations in adult male albino rats

Quinalphos is a synthetic organophosphate used as a broad spectrum insecticide and acaricide. The present study investigates the effect of three sub-lethal doses (0.52, 1.04, 2.6 mg/kg b.wt) of quinalphos for variable durations (15, 30 and 90 days) on oxidative stress and histopathological changes in adult male rats. Quinalphos treatment for 15 and 30 days resulted in a dose dependent significant increase in malondialdehyde (MDA) levels and glutathione-S-transferase (GST) activity together with a concurrent decrease in ferric reducing ability of plasma (FRAP) and glutathione (GSH) content. Quinalphos treatment for 90 days also induced a significant increase in MDA levels and GST activity but the effect was not dose-dependent. Histopathological examination of liver revealed architectural disarray and dilatation of sinusoids, focal fatty changes, accumulation of eosinophils and single cell necrosis with increasing doses. However, spleen and kidney did not show any histological changes. Administration of quinalphos resulted in oxidative stress and free radical induced injury as evidenced by increased lipid peroxidation, decreased FRAP and histopathological changes in liver.

In vitro and in vivo studies on degradation of quinalphos in rats

A pharmacokinetic in vitro and in vivo degradation study has been carried out in rat to evaluate the deleterious effects of exposure to quinalphos on a target population. Degradation of quinalphos in simulated gastric and intestinal phases has been investigated. The metabolic intermediates of quinalphos in serum and urine of albino rats at different time intervals were identified after dosing the animals with 5 mg kg(-1) body weight. All the samples were lyophilised, extracted and analysed by HPLC and GC-MS. The rate of degradation of quinalphos was accelerated in the presence of the enzymes pepsin and pancreatin contained in the gastric and intestinal simulations, respectively. Quinalphos oxon, O-ethyl-O-quinoxalin-2-yl phosphoric acid, 2-hydroxy quinoxaline and ethyl phosphoric acid are among the important metabolites identified both in in vitro and in vivo investigations. In simulated in vitro study some isomerised derivatives which were missing in the blood and urine of treated animals were identified. This could possibly be either due to non-formation or faster decay of the isomerised derivatives because of slightly different conditions prevailing in the two cases. The results also indicate that the metabolites, 2-hydroxy quinoxaline and oxon, which are more toxic than the parent compound, seem to persist for a longer time.

Endocrine-disrupting and cytotoxic potential of anticholinesterase insecticide, diazinon in reproductive toxicity of male mice

We evaluated the effects of diazinon (2, 4.1 and 8.2mg/kg bw/day for 4 weeks) in gonadotropins, testosterone and estrogen levels, whether the regulatory interactions in the hypothalamic-pituitary-testicular axis are modified by acetylcholinesterase inhibition and histopathological changes in adult mice testes. Diazinon at doses higher than 2mg/kg bw/day resulted in decreased testis weight, inhibition in acetylcholinesterase activities, decrease in levels of luteinizing hormone and follicle stimulating hormone, following reduction in mating and fertility indices. Diazinon increased testosterone content in 4.1mg/kg group, but decreased testosterone concentration in 8.2mg/kg group. Diazinon increased estrogen, prolactine and decreased levels of acetylcholinesterase activities in 4.1mg/kg group but levels of luteinizing hormone and follicle stimulating hormone remained unmodified. It may be simply postulated a scenario that acetylcholine in the cholinergic neurons has a potential threshold to perform a crucial part in the complex circuitry of neuroendocrine regulatory mechanisms. On overaccumulation, other neurotransmitters can be appropriately recruited to modulate the mechanisms of circuitry.

Histopathological effects of carbaryl on testes of snake-eyed lizard, Ophisops elegans

BACKGROUND, AIM AND SCOPE

Due to their ecological niche and insectivore nature, lizards are of increased risk of exposure to pesticides in agricultural areas. In addition to their potential direct effects on non-target species, insecticides can also result in indirect impacts on lizard population by reducing their food source. Carbaryl is a common insecticide that is widely used in areas of Turkey that are home to a variety of reptiles. However, to date, little is known about the potential effects of the exposure of reptiles such as lizards or snakes to this pesticide. The aim of the study was to investigate toxic effects of carbaryl on the testes of snake-eyed lizard, Ophisops elegans that is common to regions in Turkey where Carbaryl is applied and that it can be easily cultured in the laboratory.

MATERIAL AND METHODS

Adult male lizards were exposed to carbaryl once by oral gavage in concentrations of 2.5, 25 and 250 μg/g. After 96 h, lizards were euthanized and dissected. Histopathological changes were detected by randomly counting 100 tubules in each lizard. Seminiferous tubules were categorized as normal, sloughing and disorganized tubules. Diameters of tubules were also measured. The differences in histopathological changes and tubule diameters were compared for statistical significance by one-way ANOVA, using SPSS 16.0.

RESULTS AND DISCUSSION

Histopathological changes were more prominent in medium- (25 μg/g) and high-dose (250 μg/g) groups than in the low-dose (2.5 μg/g) group. In the medium-dose group, the hexagonal appearance of most tubules disappeared, and they took on an oval shape. Sloughing was the characteristic tubule appearance of the medium group. In the high-dose group, significant increases in the number of disorganized tubules and prominence of haemorrhages was observed.

CONCLUSION

Carbaryl caused histopathological defects on the testes of O. elegans, so it is clear that carbaryl affects male fertility in O. elegans.

Environmental chemical mediated male reproductive toxicity: Drosophila melanogaster as an alternate animal model

Industrialization and indiscriminate use of agrochemicals have increased the human health risk. Recent epidemiological studies raised a concern for male reproduction given their observations of reduced sperm counts and altered semen quality. Interestingly, environmental factors that include various metals, pesticides and their metabolites have been causally linked to such adversities by their presence in the semen at levels that correlate to infertility. The epidemiological observations were further supported by studies in animal models involving various chemicals. Therefore, in this review, we focused on male reproductive toxicity and the adverse effects of different environmental chemicals on male reproduction. However, it is beyond the scope of this review to provide a detailed appraisal of all of the environmental chemicals that have been associated with reproductive toxicity in animals. Here, we provided the evidence for reproductive adversities of some commonly encountered chemicals (pesticides/metals) in the environment. In view of the recent thrust for an alternate to animal models in research, we subsequently discussed the contributions of Drosophila melanogaster as an alternate animal model for quick screening of toxicants for their reproductive toxicity potential. Finally, we emphasized the genetic and molecular tools offered by Drosophila for understanding the mechanisms underlying the male reproductive toxicity.

Cryptotanshinone reverses reproductive and metabolic disturbances in prenatally androgenized rats via regulation of ovarian signaling mechanisms and androgen synthesis

This trial explores 1) prenatally androgenized (PNA) rats as a model of polycystic ovary syndrome (PCOS) and 2) reproductive and metabolic effects of cryptotanshinone in PNA ovaries. On days 16-18 of pregnancy, 10 rats were injected with testosterone propionate (PNA mothers) and 10 with sesame oil (control mothers). At age 3 mo, 12 female offspring from each group were randomly assigned to receive saline and 12 cryptotanshinone treatment during 2 wk. Before treatment, compared with the 24 controls, the 24 PNA rats had 1) disrupted estrous cycles, 2) higher 17-hydroxyprogesterone (P = 0.030), androstenedione (P = 0.016), testosterone and insulin (P values = 0.000), and glucose (P = 0.047) levels, and 3) higher areas under the curve (AUC) for glucose (AUC-Glu, P = 0.025) and homeostatic model assessment for insulin resistance (HOMA-IR, P = 0.008). After treatment, compared with vehicle-treated PNA rats, cryptotanshinone-treated PNA rats had 1) improved estrous cycles (P = 0.045), 2) reduced 17-hydroxyprogesterone (P = 0.041), androstenedione (P = 0.038), testosterone (P = 0.003), glucose (P = 0.036), and insulin (P = 0.041) levels, and 3) lower AUC-Glu (P = 0.045) and HOMA-IR (P = 0.024). Western blot showed that cryptotanshinone reversed the altered protein expressions of insulin receptor substrate-1 and -2, phosphatidylinositol 3-kinase p85α, glucose transporter-4, ERK-1, and 17α-hydroxylase within PNA ovaries. We conclude that PNA model rats exhibit reproductive and metabolic phenotypes of human PCOS and that regulation of key molecules in insulin signaling and androgen synthesis within PNA ovaries may explain cryptotanshinone's therapeutic effects.

House dust concentrations of organophosphate flame retardants in relation to hormone levels and semen quality parameters

BACKGROUND

Organophosphate (OP) compounds, such as tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and triphenyl phosphate (TPP), are commonly used as additive flame retardants and plasticizers in a wide range of materials. Although widespread human exposure to OP flame retardants is likely, there is a lack of human and animal data on potential health effects.

OBJECTIVE

We explored relationships of TDCPP and TPP concentrations in house dust with hormone levels and semen quality parameters.

METHODS

We analyzed house dust from 50 men recruited through a U.S. infertility clinic for TDCPP and TPP. Relationships with reproductive and thyroid hormone levels, as well as semen quality parameters, were assessed using crude and multivariable linear regression.

RESULTS

TDCPP and TPP were detected in 96% and 98% of samples, respectively, with widely varying concentrations up to 1.8 mg/g. In models adjusted for age and body mass index, an interquartile range (IQR) increase in TDCPP was associated with a 3% [95% confidence interval (CI), 5% to 1%) decline in free thyroxine and a 17% (95% CI, 432%) increase in prolactin. There was a suggestive inverse association between TDCPP and free androgen index that became less evident in adjusted models. In the adjusted models, an IQR increase in TPP was associated with a 10% (95% CI, 219%) increase in prolactin and a 19% (95% CI, 30% to 5%) decrease in sperm concentration.

CONCLUSION

OP flame retardants may be associated with altered hormone levels and decreased semen quality in men. More research on sources and levels of human exposure to OP flame retardants and associated health outcomes are needed.

Melatonin prevents damage elicited by the organophosphorous pesticide diazinon on the mouse testis

Organophosphates like O,O-diethyl O-2-isopropyl-6-methyl pyrimidinyl-4-g-1-phosphorothioate (diazinon) are pesticides used worldwide, which can affect both animals and man even after a single exposure. Whereas their toxicity is due to acetylcholinesterase inhibition, their secondary toxic effects have been related to free oxygen radicals. This study evaluates the effects of a single dose of diazinon and melatonin-a powerful antioxidant-on plasmatic acetylcholinesterase activity and testis histopathology in adult mice 1 and 32 days post-treatment. Diazinon diminished the plasma acetylcholinesterase activity on day 1 post-treatment, although testosterone levels remained unaffected. Morphometrical analysis showed a decrease in seminiferous epithelium height (days 1 and 32), whereas an increase in testicular superoxide dismutase (SOD) activity was detected (day 32). Melatonin pretreatment prevented every alteration induced by diazinon, except the diminution of acetylcholinesterase plasmatic activity. Testicular damage might be due to elevated concentrations of free oxygen radicals released upon diazinon exposure, inducing alterations in the DNA and promoting local apoptosis; however, antioxidant pretreatment with melatonin prevents or diminishes this damage.

Semen quality in Peruvian pesticide applicators: association between urinary organophosphate metabolites and semen parameters

BACKGROUND

Organophosphates are broad class of chemicals widely used as pesticides throughout the world. We performed a cross-sectional study of associations between dialkylphosphate metabolites of organophosphates and semen quality among pesticide applicators in Majes (Arequipa), Peru.

METHODS

Thirty-one men exposed to organophosphate (OP) pesticides and 31 non-exposed were recruited (age, 20-60 years). In exposed subjects, semen and a blood sample were obtained one day after the last pesticide application. Subjects were grouped according to levels of OP metabolites in urine. Semen samples were analyzed for sperm concentration, percentage of sperm motility, percentage of normal morphology, semen leucocytes and concentrations of fructose and zinc. Exposure to OP was assessed by measuring six urinary OP metabolites (dimethyl and diethyl phosphates and thiophosphates) by gas chromatography using a single flame photometric detector.

RESULTS

Diethyldithiophosphate (p = 0.04) and diethylthiophosphate (p = 0.02) better reflected occupational pesticide exposure than other OP metabolites. Semen analysis revealed a significant reduction of semen volume and an increase in semen pH in men with OP metabolites. Multiple regression analysis showed that both occupational exposure to pesticides and the time of exposure to pesticides were more closely related to alterations in semen quality parameters than the single measurement of OP metabolites in urine.

CONCLUSION

The study demonstrated that occupational exposure to OP pesticides was more closely related to alterations in semen quality than a single measurement of urine OP metabolites. Current measurement of OP metabolites in urine may not reflect the full risk.

Dichlorvos-induced hepatotoxicity in rats and the protective effects of vitamins C and E

Dichlorvos is an organophosphate insecticide that is widely used in pest control. Vitamin C (200mg/kg)+vitamin E (200mg/kg), dichlorvos (1.6mg/kg), or a combination of vitamin C (200mg/kg)+vitamin E (200mg/kg)+dichlorvos (1.6mg/kg) was given to rats via oral gavage for 7 weeks. When rats of the dichlorvos-treated group and the vitamins+dichlorvos-treated group were compared with the control group, body weights were decreased and liver weights were increased significantly at the end of the 4th and 7th week. Serum total protein, albumin, triglyceride, low density lipoprotein-cholesterol (VLDL-cholesterol) levels were decreased, and serum alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyl-transferase (GGT), lactate dehydrogenase (LDH), and total cholesterol levels were increased significantly at the end of the 4th and 7th week in the dichlorvos- and vitamins+dichlorvos-treated rats. There was a statistically significant difference for all biochemical parameters when the vitamins+dichlorvos-treated group was compared with the dichlorvos-treated group at the end of the 4th and 7th week. In an electron microscopic investigation, swelling of mitochondria and dilatation of endoplasmic reticulum were observed in liver cells of the dichlorvos- and vitamins+dichlorvos-treated rats at the end of the 4th and 7th week. As a result, vitamins C and E reduced dichlorvos hepatotoxicity, but vitamins C and E did not confer complete protection.

Testicular functions and serum titers of LH and testosterone in methyl parathion-fed roseringed parakeets

Adult male roseringed parakeets were fed concentrations (0, 10 or 20 microg/100g body wt./day) of methyl parathion (MP) for 5 or 10 days. There were four sampling periods for each treatment group. The first two sampling periods were after 5 or 10 days of daily dosing. In two other sampling periods, birds were given daily doses for 10 days, and sampling occurred at 5 or 10 days after the end of treatment. A significant dose- and duration-dependent reduction in the paired testicular weight, seminiferous tubular diameters, the number of tubules with healthy germ cells, plasma acetylcholinesterase (AChE) activity and plasma levels of luteinizing hormone (LH) and testosterone occurred in MP-fed birds. The inhibitory influences of MP persisted till day-5 and followed by recovery from the gonado-suppressive effects of MP at day-10 after the end of last treatment for 10 days. These findings provide the first experimental evidence that MP-induced testicular dysfunctions in parakeets possibly results from an impaired activity of hypophysial-gonadal axis. Moreover, it is evident that the organophosphorous (OP)-induced changes in the avian testes are reversible.

In vitro and in vivo reduction of sodium arsenite induced toxicity by aqueous garlic extract

BACKGROUND

Arsenic is ubiquitous in the environment, and chronic or acute exposure through food and water as well as occupational sources can contribute to a well-defined spectrum of disease. Despite arsenic being a health hazard and a well-documented human carcinogen, a safe, effective and specific preventive or therapeutic measure for treating arsenic induced toxicity still eludes us.

OBJECTIVE

This study was undertaken to evaluate the therapeutic efficacy of aqueous garlic (Allium sativum L.) extract (AGE) in terms of normalization of altered biochemical parameters particularly indicative of oxidative stress following sodium arsenite (NaAsO(2)) exposure and depletion of inorganic arsenic burden, in vitro and in vivo.

RESULTS

AGE (2mg/ml) co-administered with 10 microM NaAsO(2) attenuated arsenite induced cytotoxicity, reduced intracellular reactive oxygen species (ROS) level in human malignant melanoma cells (A375), human keratinocyte cells (HaCaT) and in cultured human normal dermal fibroblast cells. Moreover, AGE application in NaAsO(2) intoxicated Sprague-Dawley rats resulted in a marked inhibition of tissue lipid peroxide generation; enhanced level of total tissue sulfhydryl groups and glutathione; and also increased the activities of antioxidant enzymes, superoxide dismutase and catalase to near normal. An increase in blood ROS level and myeloperoxidase activity in arsenic-intoxicated rats was effectively prevented by AGE administration. AGE was also able to counter arsenic mediated incongruity in blood hematological variables and glucose level.

CONCLUSIONS

The restorative property of AGE was attributed to its antioxidant activity, chelating efficacy, and/or oxidizing capability of trivalent arsenic to its less toxic pentavalent form. Taken together, evidences indicate that AGE can be a potential protective regimen for arsenic mediated toxicity.

Histopathological effects of dimethoate on testes of rats

The aim of the current study was to investigate subchronic effect of dimethoate on the testes of rats. The animals of exposed groups were fed with laboratory chow combined with 2, 8 and 20 mg/kg dimethoate for 90 days. When compared to control, there was a statistically significant decrease in relative testis weights of rats treated with 20 mg/kg dimethoate. In light microscopic examinations, histopathological observation of the treated rats revealed that dimethoate caused dose-related testicular damage characterized by moderate to severe seminiferous tubule degeneration as sloughing, atrophy, germ cell degeneration and by partial arrest of spermatogenesis.

Toxicity of the quinalphos metabolite 2-hydroxyquinoxaline: growth inhibition, induction of oxidative stress, and genotoxicity in test organisms

The quinalphos metabolite 2-hydroxyquinoxaline (HQO), previously shown to photocatalytically destroy antioxidant vitamins and biogenic amines in vitro, was tested for toxicity in several small aquatic organisms and for mutagenicity in Salmonella typhimurium. In the rotifer Philodina acuticornis, HQO caused the disappearance of large individuals and increased hydroperoxide concentration. The latter effect was not only observed in animals kept in a light/dark cycle, but also in constant darkness, indicating that HQO can assume a reactive state and/or form reactive intermediates under the influence of either light or redox-active metabolites, in particular, free radicals. Cell proliferation was inhibited in the ciliate Paramecium bursaria. In the dinoflagellate Lingulodinium polyedrum, which allows early detection of cellular stress on the basis of bioluminescence measurements, strong rises in light emission became apparent on the 2nd day of exposure to HQO and continued until cells died between 12 and 18 days of treatment. Oxidative damage of protein by HQO was demonstrated by measuring protein carbonyl in L. polyedrumin vivo as well as in light-exposed bovine serum albumin in vitro. In an Ames test of mutagenicity, HQO proved to be genotoxic in both light- and dark-exposed bacteria. HQO appears as a source of secondary quinalphos toxicity, which deserves further attention.

Effect of two insecticides and two herbicides on the porcine sperm motility patterns using computer-assisted semen analysis (CASA) in vitro

The recent decline in sperm concentration observed in men has developed over a short period of time, suggesting that it could be the result of environmental factors. The present study has evaluated the effects of insecticides Malathion and Diazinon, and herbicides Atrazine and Fenoxaprop-Ethyl on porcine sperm viability and motility patterns in vitro using the eosin-nigrosin staining and a computer-assisted semen analyzer (CASA), respectively. Malathion and Fenoxaprop-Ethyl exerted more deleterious effects than Diazinon and Atrazine. Progressive sperm motility was strongly affected whereas the effect on sperm viability was less pronounced. This suggests that a reduction of sperm motility is not necessarily the result of sperm death. Since sperm motility is dependent on energy metabolism the mechanism of action of these pesticides might be mediated at the level of the mitochondrion, producing a delay in motility and eventual cell death.

Efficient testing strategies for evaluation of xenobiotics with neuroendocrine activity

Maturation of neuroendocrine regulations is an extremely complex process made up of several stages, that can be permanently affected by any exogenous substances able to interfere with the hormonal signalling at various levels. The Endocrine Disrupting Chemicals (EDCs) are a heterogeneous group of xenobiotics with potential endocrine activities which have been identified as priority risk factors in toxicological research. The present review is aimed at suggesting a number of endocrine and behavioural endpoints to be used in experimental studies to: (i) characterize more thoroughly the functional effects of developmental exposure to agents known to act as endocrine disruptors and (ii) unmask possible interferences with the maturation of the hypothalamus-hypophysis-gonad/thyroid (HHG/Th) axis by different class of xenobiotics not considered as EDCs. A combined testing strategy, considering both markers of endocrine/hormonal maturation and behavioural endpoints under hormonal control in laboratory rodents, may evidence even subtle perturbations of the neuroendocrine homeostasis, that often go undetected.

Effects of chronic exposure to sodium arsenite on hypothalamo-pituitary-testicular activities in adult rats: possible an estrogenic mode of action

BACKGROUND

Inorganic arsenic is a major water pollutant and a known human carcinogen that has a suppressive influence on spermatogenesis and androgenesis in male reproductive system. However, the actual molecular events resulting in male reproductive dysfunctions from exposure to arsenic remain unclear. In this context, we evaluated the mode of action of chronic oral exposure of sodium arsenite on hypothalamo-pituitary- testicular activities in mature male albino rats.

METHODS

The effect of chronic oral exposure to sodium arsenite (5 mg/kg body weight/day) via drinking water without or with hCG (5 I.U./kg body weight/day) and oestradiol (25 micrograms oestradiol 3-benzoate suspended in 0.25 ml olive oil/rat/day) co-treatments for 6 days a week for 4 weeks (about the duration of two spermatogenic cycle) was evaluated in adult male rats. Changes in paired testicular weights, quantitative study of different varieties of germ cells at stage VII of spermatogenic cycle, epididymal sperm count, circulatory concentrations of hormones (LH, FSH, testosterone and corticosterone), testicular activities of delta 5, 3beta-hydroxysteroid dehydrogenase (delta 5, 3beta-HSD), 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD), sorbitol dehydrogenase (SDH), acid phosphatase (ACP), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH), as well as the levels of biogenic amines (dopamine, noradrenaline and 5-hydroxytryptamine (5-HT)) in the hypothalamus and pituitary were monitored in this study. Hormones were assayed by radioimmuno- assay or enzyme- linked immunosorbent assay and the enzymes were estimated after spectrophotometry as well as the biogenic amines by HPLC electrochemistry.

RESULTS

Sodium arsenite treatment resulted in: decreased paired testicular weights; epididymal sperm count; plasma LH, FSH, testosterone and testicular testosterone concentrations; and increased plasma concentration of corticosterone. Testicular enzymes such as delta 5, 3 beta-HSD, 17 beta-HSD, and sorbitol dehydrogenase (SDH) were significantly decreased, but those of acid phosphatase (ACP), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) were significantly increased. A decrease in dopamine or an increase in noradrenaline and 5-HT in hypothalamus and pituitary were also noted after arsenic exposure. Histological evaluation revealed extensive degeneration of different varieties of germ cells at stage VII of spermatogenic cycle in arsenic exposed rats. Administration of human chorionic gonadotrophin (hCG) along with sodium arsenite partially prevented the degeneration of germ cells and enhanced paired testicular weights, epididymal sperm count, plasma and intratesticular testosterone concentrations, activities of delta 5, 3beta-HSD, 17 beta-HSD and sorbitol dehydrogenase along with diminution in the activities of ACP, ALP and LDH. Since many of the observed arsenic effects could be enhanced by oestradiol, it is suggested that arsenic might somehow acts through an estrogenic mode of action.

CONCLUSION

The results indicate that arsenic causes testicular toxicity by germ cell degeneration and inhibits androgen production in adult male rats probably by affecting pituitary gonadotrophins. Estradiol treatment has been associated with similar effects on pituitary testicular axis supporting the hypothesis that arsenite might somehow act through an estrogenic mode of action.

Effect of chlorpyrifos-methyl on steroid and thyroid hormones in rat F0- and F1-generations

Chlorpyrifos-methyl (CPM) suppressed androgenic activity in Hershberger assay using castrated rats. Acute oral lowest-observed-adverse-effect-level (LOAEL) and no-observed-adverse-effect-level (NOAEL) was evaluated as 12 and 0.1 mg/kg bw, respectively, based on its major effect of cholinesterase inhibition. Also, repeated oral NOAEL was 0.1 mg/kg bw/day based on adrenal damage in rats. We investigated one-generation reproductive toxicity of CPM focusing on endocrine-disrupting effects by the administration of 1, 10 and 100 mg/kg bw/day CPM to mature SD rats (F0) through pre-mating, mating, gestation and lactation period and to their offspring (F1) until 13 weeks age via gavage. A group treated with corn oil served as vehicle control. In F0 rats, the most affected organs were adrenal glands as increased in weight at all doses of CPM in males and at 10 and 100 mg/kg CPM in females and adrenal vacuolation at CPM 10 and 100 mg/kg. The relative and absolute ovaries and the absolute seminal vesicle weights were decreased but the weights of liver, spleen or kidneys were increased at 100 mg/kg CPM. Parameters representing reproductive performances as mating ratio, gestation length and delivery index were not affected, except for decreased fertility index and numbers of implantation and born pups and a higher male sex ratio of pups at CPM 100 mg/kg. F1 pups exposed to CPM 100 mg/kg in utero and via maternal milk showed lower body weight with changes of absolute or relative weights of brain, ovary, liver, spleen and epididymis and decreased absolute not relative anogenital distance at weanling time. The time of vaginal patency and preputial separation and estrous cycling pattern of F1 rats were not impacted by CPM. After further 10 weeks oral administration until 13 weeks old, adrenal glands, brain, liver, spleen or kidneys tended to be increased, while thyroid gland, testes and ventral prostate of F1 male rats were decreased at CPM 10 or 100 mg/kg. Histopathologically, necrosis or vacuolation of thyroid follicular epithelial cells and adrenal cortical cells were observed at all doses of CPM. Serum levels of estradiol, testosterone, T4 and T3 were significantly lower while TSH and cholesterol were higher in both F1 female and male rats treated with CPM though dose-responsiveness was not clear in F1 females. Decreased sperm were counted in F1 rats at CPM 100 mg/kg. As a whole, LOAEL and NOAEL was evaluated as 10 and 1 mg/kg bw, respectively, based on decreased estradiol and T4 and increased TSH in serum of F1 male rats, and when considering histopathological alteration of adrenal and thyroid glands, LOAEL assumed to be lower than 1 mg/kg bw. This study elucidates that CPM exhibit weak reproductive toxicity in F0 rats exposed at adulthood and negligible effects in F1 offspring exposed in utero and via lactation at weanling, but induce anti-androgenic effect and hypothyroidism after long term exposure from in utero through sexual maturation of F1 rats.

Pesticide exposure alters follicle-stimulating hormone levels in Mexican agricultural workers

Organophosphorous pesticides (OPs) are suspected of altering reproductive function by reducing brain acetylcholinesterase activity and monoamine levels, thus impairing hypothalamic and/or pituitary endocrine functions and gonadal processes. Our objective was to evaluate in a longitudinal study the association between OP exposure and serum levels of pituitary and sex hormones. Urinary OP metabolite levels were measured by gas-liquid chromatography, and serum pituitary and sex hormone levels by enzymatic immunoassay and radioimmunoassay in 64 men. A total of 147 urine and blood samples were analyzed for each parameter. More than 80% of the participants had at least one OP metabolite in their urine samples. The most frequent metabolite found was diethylthiophosphate (DETP; 55%), followed by diethylphosphate (DEP; 46%), dimethylthiophosphate (DMTP; 32%), and dimethyldithiophosphate (DMDTP; 31%). However, the metabolites detected at higher concentrations were DMTP, DEP, DMDTP, and dimethylphosphate. There was a high proportion of individuals with follicle-stimulating hormone (FSH) concentrations outside the range of normality (48%). The average FSH serum levels were higher during the heavy pesticide spraying season. However, a multivariate analysis of data collected in all periods showed that serum FSH levels were negatively associated with urinary concentrations of both DMTP and DMDTP, whereas luteinizing hormone (LH) was negatively associated with DMTP. We observed no significant associations between estradiol or testosterone serum levels with OP metabolites. The hormonal disruption in agricultural workers presented here, together with results from experimental animal studies, suggests that OP exposure disrupts the hypothalamic-pituitary endocrine function and also indicates that FSH and LH are the hormones most affected.

Chlropyrifos-methyl shows anti-androgenic activity without estrogenic activity in rats

Chlorpyrifos-methyl (CPM), an organophosphate insecticide, widely used for grain storage and agriculture, has been suspected as endocrine disrupter by a few in vitro studies. This study was performed to investigate the (anti-) estrogenicity and (anti-) androgenicity of CPM in vivo using immature rat uterotrophic assay and rat Hershberger assay. CPM with or without 17beta-estradiol were administered to 20 days old female rats to investigate its (anti-) estrogenic activity. Uterine and vaginal weight, uterine epithelial cell height were not affected by the treatment of CPM (2, 10, 50, 250 mg/kg). CPM 250 mg/kg potentiated relative vagina weight in 17beta-estradiol treated immature female rats without any changing of uterine weight. Relative liver weight was increased with decrease of body weight by CPM 250 mg/kg treatment. Uterine cell proliferation tested with bromodeoxyuridine labeling index was not observed in CPM treated rats. CPM with or without testosterone propionate were administered to castrated rat of 51 days old for 10 days to investigate the (anti-)androgenic activity,. The weight of relative and absolute androgen-dependent accessory sex organs; seminal vesicle with coagulating glands (SV/CG), ventral prostate gland (VP), glans penis (GP), levator ani plus bulbocarvernosus muscle (LABC) and Cowper's gland (CG,) were unchanged by the treatment of CPM alone. While CPM induced the increase of relative adrenal gland weight, CPM 50mg/kg decreased the weights of CV/CG, VP, CG and LABC without change of GP without changing of GP when it was treated with TP. In conclusion, CPM dose not show estrogenic and anti-estrogenic activity in immature female rats, but it represents anti-androgenic activity by inhibition of the TP-stimulated increase of the weight of accessory sex organs.

Temporal effects of mancozeb on testes, accessory reproductive organs and biochemical constituents in albino mice

Mancozeb, a fungicide of ethylenebisdithiocarbamate group was orally administered at 800 mg/kg body weight to male Swiss albino mice for 5, 10, 20 and 30 days. Daily body weight of the mice were recorded. The mice were sacrificed by cervical dislocation after 24 h of terminal exposure of mancozeb. Testes weight decreased significantly in 20 and 30 days mancozeb treated mice. However, there was a significant decrease in the number of spermatogonia, diameter of spermatocytes and spermatids in 20 days and number of spermatids in 10 days mancozeb treated mice. Histologic studies of the testis of the mice treated with mancozeb for long duration revealed spermatogenesis inhibition reflected by significant decrease in the number of spermatogenic cells and sperms, when compared with that of controls. In the mice treated with mancozeb for 20 and 30 days showed significant decrease in the weight of the prostate gland. However weight of Cowper's glands decreased significantly in 30 days mancozeb treated mice. There was significant decrease in the kidney, spleen and liver weight, where as thyroid weight increased significantly in mice treated with mancozeb for 30 days. However, thymus weight increased significantly only in the mice treated with mancozeb for 10, 20 and 30 days. In mice treated with mancozeb for 20 days caused significant decrease in the level of protein and a significant increase in the level of total lipids in the testis. However, there was significant decrease in the level of glycogen in the kidney. In mice treated with mancozeb for 30 days caused significant decrease in the levels of protein and glycogen and significant increase in the level of total lipids in the testis and liver and a significant decrease in the protein, glycogen and total lipids in the kidney. These observed effects of mancozeb on testis and biochemical constituents may be due to hormonal imbalance in any of the stages in the hypothalamo-hypophysial-testicular axis.

Modified testicular expression of stress-associated "readthrough" acetylcholinesterase predicts male infertility

Male infertility is often attributed to stress. However, the protein or proteins that mediate stress-related infertility are not yet known. Overexpression of the "readthrough" variant of acetylcholinesterase (AChE-R) is involved in the cellular stress response in a variety of mammalian tissues. Here, we report testicular overexpression of AChE-R in heads, but not tails, of postmeiotic spermatozoa from mice subjected to a transient psychological stress compared with age-matched control mice. Transgenic mice overexpressing AChE-R displayed reduced sperm counts, decreased seminal gland weight, and impaired sperm motility compared with age-matched nontransgenic controls. AChE-R was prominent in meiotic phase spermatocytes and in tails, but not heads, of testicular spermatozoa from AChE-R transgenic mice. Head-localized AChE-R was characteristic of human sperm from fertile donors. In contrast, sperm head AChE-R staining was conspicuously reduced in samples from human couples for whom the cause of infertility could not be determined, similar to the pattern found in transgenic mice. These findings indicate AChE-R involvement in impaired sperm quality, which suggests that it is a molecular marker for stress-related infertility.