RESUMEN
Methamidophos (MET) is a highly toxic organophosphate (OP) pesticide that is widely used in developing countries. MET has male reproductive effects, including decreased fertility. We evaluated MET effects on sperm quality, fertilization and DNA integrity, exploring the sensitivity of different stages of spermatogenesis. Adult male mice received MET (3.75 or 5mg/kg-bw/ip/day/4 days) and were euthanized 1, 28 or 45 days post-treatment (dpt) to evaluate MET's effects on epididymal maturation, meiosis or mitosis, respectively. Spermatozoa were obtained from the cauda epididymis-vas deferens and were evaluated for sperm quality, acrosome reaction (AR; Coomassie staining), mitochondrial membrane potential (by JC-1), DNA damage (comet assay), oxidative damage (malondialdehyde (MDA) production), in vitro fertilization and protein phosphorylation (immunodetection), and erythrocyte acetylcholinesterase (AChE) activity. At 1-dpt, MET inhibited AChE (43-57%) and increased abnormal cells (6%). While at 28- and 45-dpt, sperm motility and viability were significantly reduced with an increasing MET dose, and abnormal morphology increased at 5mg/kg/day/4 days. MDA and mitochondrial activity were not affected at any dose or time. DNA damage (OTM and %DNA) was observed at 5mg/kg/day/4 days in a time-dependent manner, whereas both parameters were altered in cells from mice exposed to 3.75 mg/kg/day/4 days only at 28-dpt. Depending on the time of collection, initial-, spontaneous- and induced-AR were altered at 5mg/kg/day/4 days, and the fertilization capacity also decreased. Sperm phosphorylation (at serine and tyrosine residues) was observed at all time points. Data suggest that meiosis and mitosis are the more sensitive stages of spermatogenesis for MET reproductive toxicity compared to epididymal maturation.
Asunto(s)
Replicación del ADN/efectos de los fármacos , Insecticidas/toxicidad , Compuestos Organotiofosforados/toxicidad , Espermatogénesis/efectos de los fármacos , Espermatozoides/efectos de los fármacos , Acetilcolinesterasa/metabolismo , Reacción Acrosómica/efectos de los fármacos , Animales , Peso Corporal/efectos de los fármacos , Ensayo Cometa , Femenino , Fertilización/efectos de los fármacos , Técnicas In Vitro , Infertilidad Masculina/inducido químicamente , Infertilidad Masculina/patología , Peroxidación de Lípido/efectos de los fármacos , Masculino , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Ratones , Ratones Endogámicos ICR , Oocitos/efectos de los fármacos , Tamaño de los Órganos/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Fosforilación , Reproducción/efectos de los fármacosRESUMEN
Methamidophos (MET), widely used in developing countries, is a highly neurotoxic organophosphate pesticide that has been associated with male reproductive alterations. Commercial formulations of pesticides used by agricultural workers and urban sprayers are responsible for thousands of intoxications in developing countries and may not have the same effects as active pure ingredients. Therefore, we compared effects of MET technical (METt) and commercial (METc) grades on sperm quality and DNA integrity. Male mice were injected (intraperitoneal, i.p.) with METt or METc (3.75, 5, and 7 mg/kg bw/day/4 days) and sacrificed 24 h post-treatment. Sperm cells collected from epididymis-vas deferens were evaluated for quality parameters, DNA damage by the comet assay, and lipoperoxidation by malondialdehyde (MDA) production. Erythrocyte acetylcholinesterase (AChE) activity was evaluated by acetylthiocholine inhibition as an index of overall toxicity. A dose-dependent AChE inhibition was observed with both formulations. Sperm quality was decreased after treatment with both MET compounds, but the commercial formulation showed stronger effects; a similar profile was observed with the DNA damage, being METc more genotoxic. None MET formulation increased MDA, suggesting no peroxidative damage involved. In summary, the commercial formulation of MET was more reprotoxic and genotoxic than the active pure ingredient, highlighting that commercial formulations must be considered for more appropriate risk assessment of pesticide exposures.
Asunto(s)
Daño del ADN , Compuestos Organotiofosforados/toxicidad , Plaguicidas/toxicidad , Acetilcolinesterasa/sangre , Animales , Ensayo Cometa , ADN/farmacología , Eritrocitos/efectos de los fármacos , Eritrocitos/enzimología , Peroxidación de Lípido , Masculino , Malondialdehído/metabolismo , Ratones , Ratones Endogámicos ICR , Reproducción/efectos de los fármacos , Espermatozoides/citología , Espermatozoides/efectos de los fármacosRESUMEN
Pesticides have been considered as potential chemical mutagens; however, little is known about toxic and genotoxic effects during pesticide application in Zamora-Jacona, Michoacan State in Mexico. This study sought to determine DNA damage and cholinesterase activities inhibitions in 54 agricultural workers exposed to complex mixtures of pesticides vs. control group (26 individuals) using Comet assay in peripheral whole blood, micronucleus (MN) test in oral mucosa cells, Cytokinesis-blocked MN assay in lymphocytes (L-CBMNcyt) and measuring AChE and BChE activities in whole blood and plasma samples, respectively. Exposed subjects demonstrated significantly elevated levels of primary (Comet assay: tail intensity, tail length, tail moment, Olive tail moment) and permanent DNA damage (MN assay: in blood/buccal cells; frequencies of nuclear buds, binucleated cells, cells with condensed chromatin, karyorrhexis, pyknosis, and karyolysis). However, inhibition of cholinesterase activities (AChE and BChE) was not observed in the workers. Confounding factors including sex, age, BMI, working exposure period, protection level, smoking habit (cigarettes per day units), alcohol consumption (weekly), medication, were considered in the analysis. These combined techniques demonstrated usefulness in the health hazards risks pesticide exposure assessment and suggested the need for periodic monitoring together with the education and the training of occupational workers for the safe application of potentially harmful pesticides.
Asunto(s)
Exposición Profesional , Plaguicidas , Colinesterasas , Ensayo Cometa , Análisis Citogenético , Daño del ADN , Humanos , Linfocitos , México , Pruebas de Micronúcleos , Mucosa Bucal , Exposición Profesional/efectos adversos , Exposición Profesional/análisis , Plaguicidas/toxicidadRESUMEN
Methyl parathion (Me-Pa) is an extremely toxic organophosphorus pesticide still used in developing countries. It has been associated with decreased sperm function and fertility and with oxidative and DNA damage. The blood-testis barrier (BTB) is a structure formed by tight junction (TJ) proteins in Sertoli cells and has a critical role in spermatogenesis. We assessed the effect of repeated doses of Me-Pa (3-12 mg/kg/day for 5 days, i.p.) on sperm quality, lipid oxidation, DNA integrity, and BTB permeability in adult male mice and explored oxidation as a mechanism of toxicity. Me-Pa caused dose-dependent effects on sperm quality, lipoperoxidation, and DNA integrity. Testis histology results showed the disruption of spermatogenesis progression and atrophy of seminiferous tubules. The pesticide opened the BTB, as evidenced by the presence of a biotin tracer in the adluminal compartment of the seminiferous tubules. This effect was not observed after 45 days of exposure when a spermatogenic cycle had completed. The coadministration of the antioxidant α-tocopherol (50 mg/kg/day for 5 days, oral) prevented the effects of Me-Pa on sperm quality, DNA and the BTB, indicating the importance of oxidative stress in the damage generated by Me-Pa. As evidenced by immunochemistry, no changes were found in the localization of the TJ proteins of the BTB, although oxidation (carbonylation) of total proteins in testis homogenates was detected. Our results show that Me-Pa disturbs the BTB and that oxidation is involved in the observed toxic effects on sperm cells.
Asunto(s)
Barrera Hematotesticular/efectos de los fármacos , Permeabilidad Capilar/efectos de los fármacos , Inhibidores de la Colinesterasa/toxicidad , Daño del ADN , Metil Paratión/toxicidad , Estrés Oxidativo/efectos de los fármacos , Plaguicidas/toxicidad , Espermatozoides/efectos de los fármacos , Acetilcolinesterasa/metabolismo , Animales , Antioxidantes/farmacología , Barrera Hematotesticular/metabolismo , Barrera Hematotesticular/patología , Proteínas Ligadas a GPI/antagonistas & inhibidores , Proteínas Ligadas a GPI/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Masculino , Ratones Endogámicos ICR , Carbonilación Proteica/efectos de los fármacos , Espermatogénesis/efectos de los fármacos , Espermatozoides/metabolismo , Espermatozoides/patologíaRESUMEN
Because di(2-ethylhexyl) phthalate (DEHP) toxicity on ovarian function is incomplete, effects of DEHP oocyte fertilization and the resulting zygotes were investigated. Further, an analysis characterizing the stage of zygote arrest was performed. Female CD1 mice were dosed orally with DEHP (0, 20, 200 and 2000⯵g/kg/day) for 30 days. Following an in vivo mating post-dosing, DEHP-treated females exhibited fewer oocytes/zygotes, fewer oocytes displaying the polar body extrusion, fewer 1-cell zygotes having 2-pronuclei, more unfertilized oocytes, and decreased number of zygotes at every stage of development. DEHP induced blastomere fragmentation in zygotes. DNA replication in zygotes directly assessed by the 5-Ethynyl-2'-deoxyuridine (5-EdU) incorporation assay and indirectly by dosing mice with 5-fluorouracil (5-FU) suggested that DEHP inhibits DNA replication. Our data suggest that DEHP at doses found in 'every-day' (200⯵g/Kg/day) or occupational (2000⯵g/Kg/day) environments induces zygote fragmentation and arrests its development from the 2-cell stage potentially impairing DNA replication.
Asunto(s)
Dietilhexil Ftalato/toxicidad , Contaminantes Ambientales/toxicidad , Oocitos/efectos de los fármacos , Plastificantes/toxicidad , Cigoto/efectos de los fármacos , Administración Oral , Animales , Femenino , Fertilización/efectos de los fármacos , Masculino , RatonesRESUMEN
Exposure to malathion (an organophosphate pesticide widely used around the world) has been associated with alterations in blood glucose concentration in animal models. However, the results are inconsistent. The aim of this meta-analysis was to evaluate whether malathion exposure can disturb the concentrations of blood glucose in exposed rats. We performed a literature search of online databases including PubMed, EBSCO, and Google Scholar and reviewed original articles that analyzed the relation between malathion exposure and glucose levels in animal models. The selection of articles was based on inclusion and exclusion criteria. The database search identified thirty-five possible articles, but only eight fulfilled our inclusion criteria, and these studies were included in the meta-analysis. The effect of malathion on blood glucose concentration showed a non-monotonic dose-response curve. In addition, pooled analysis showed that blood glucose concentrations were 3.3-fold higher in exposed rats than in the control group (95% CI, 2-5; Z = 3.9; p < 0.0001) in a random-effect model. This result suggested that alteration of glucose homeostasis is a possible mechanism of toxicity associated with exposure to malathion.