Effects of captan, mancozeb and azoxystrobin fungicides on motility, oxidative stress and fatty acid profiles in rainbow trout (Oncorhynchus mykiss) spermatozoa.

An in vitro study using rainbow trout spermatozoa was designed to evaluate the toxic effects of different concentrations of captan (CPT), mancozeb (MCZ), and azoxystrobin (AZX) fungicides on motility parameters, lipid peroxidation, SOD activity, total antioxidant capacity (TAC), and DPPH inhibition. Moreover, changes in fatty acids profiles caused by the fungicides were determined for the first time. The results revealed that motility parameters, SOD activities, TAC values, and DPPH inhibitions decreased significantly while lipid peroxidation increased after ≥2 µg/L of CPT, ≥1 µg/L of MCZ, and ≥5 µg/L of AZX incubations for 2 h at 4 °C. Additionally, 10 µg/L CPT, 5 µg/L MCZ, and 200 µg/L AZX reduced motility to the 50 % level. Our results clearly demonstrated significant changes in the fatty acids profiles of spermatozoa exposed to these concentrations of the fungicides. The highest lipid peroxidation and the lowest monounsaturated and polyunsaturated saturated fatty acids (MUFA and PUFA, respectively) were detected in AZX. Even though the susceptibility of spermatozoa to oxidative damage is generally attributed to PUFA contents, the results of this study have represented that MUFA content could play a part in this tendency. Moreover, the lower concentration of MCZ reduced motility to the % 50 level while it deteriorated the fatty acids profile less than did AZX. Overall, the present study demonstrated that the detrimental effects of the fungicides on mitochondrial respiration and related enzymes have more priority than oxidative stress in terms of their toxicities on spermatozoa. It has also been suggested that fish spermatozoa are a good model for determining changes in the fatty acid profiles by fungicides, probably, by other pesticides and environmental contaminants as well.

Investigation on the mancozeb toxicity in adult zebrafish (Danio rerio).

Agriculture has gained increasing importance in response to the continuous growth of the world population and constant need for food. To avoid production losses, farmers commonly use pesticides. Mancozeb is a fungicide used in agriculture as this compound is effective in combating fungi that harm crops. However, this fungicide may also produce damage to non-target organisms present in soil and water. Therefore, this study aimed to investigate the influence of exposure to mancozeb on survival rate, locomotor activity, behavior, and oxidative status utilizing adult zebrafish (Danio rerio) as a model following exposure to environmentally relevant concentrations of this pesticide. The experimental groups were negative control, positive control, and mancozeb (0.3; 1.02; 3.47; 11.8 or 40 µg/L). Zebrafish were exposed to the respective treatments for 96 hr. Exposure to mancozeb did not markedly alter survival rate and oxidative status of Danio rerio. At a concentration of 11.8 µg/L, the fungicide initiated changes in locomotor pattern of the animals. The results obtained suggest that the presence of mancozeb in the environment might produce locomotor alterations in adult zebrafish, which subsequently disrupt the animals' innate defense mechanisms. In nature, this effect attributed to mancozeb on non-target organisms might result in adverse population impacts and ecological imbalance.

Low concentrations of ethylene bisdithiocarbamate pesticides maneb and mancozeb impair manganese and zinc homeostasis to induce oxidative stress and caspase-dependent apoptosis in human hepatocytes.

The worldwide and intensive use of phytosanitary compounds results in environmental and food contamination by chemical residues. Human exposure to multiple pesticide residues is a major health issue. Considering that the liver is not only the main organ for metabolizing pesticides but also a major target of toxicities induced by xenobiotics, we studied the effects of a mixture of 7 pesticides (chlorpyrifos-ethyl, dimethoate, diazinon, iprodione, imazalil, maneb, mancozeb) often detected in food samples. Effects of the mixture was investigated using metabolically competent HepaRG cells and human hepatocytes in primary culture. We report the strong cytotoxicity of the pesticide mixture towards hepatocytes-like HepaRG cells and human hepatocytes upon acute and chronic exposures at low concentrations extrapolated from the Acceptable Daily Intake (ADI) of each compound. Unexpectedly, we demonstrated that the manganese (Mn)-containing dithiocarbamates (DTCs) maneb and mancozeb were solely responsible for the cytotoxicity induced by the mixture. The mechanism of cell death involved the induction of oxidative stress, which led to cell death by intrinsic apoptosis involving caspases 3 and 9. Importantly, this cytotoxic effect was found only in cells metabolizing these pesticides. Herein, we unveil a novel mechanism of toxicity of the Mn-containing DTCs maneb and mancozeb through their metabolization in hepatocytes generating the main metabolite ethylene thiourea (ETU) and the release of Mn leading to intracellular Mn overload and depletion in zinc (Zn). Alteration of the Mn and Zn homeostasis provokes the oxidative stress and the induction of apoptosis, which can be prevented by Zn supplementation. Our data demonstrate the hepatotoxicity of Mn-containing fungicides at very low doses and unveil their adverse effect in disrupting Mn and Zn homeostasis and triggering oxidative stress in human hepatocytes.

Determinación de etilentiourea en acelgas tratadas con Zineb: Efecto del calor húmedo por ebullición / Determination of ethylenethiourea in chard treated with Zineb: Effect of wet heat by boiling

El Zineb es un plaguicida perteneciente a la familia de los etilenbisditiocarbamatos (EBDC) ampliamente utilizado en la provincia de Jujuy (Argentina). La toxicidad de este fungicida está dada por la etilentiourea (ETU) que es el principal producto de su degradación. La ETU tiene efectos mutagénicos, teratogénicos y cancerígenos en animales. La EPA la clasifica como probable cancerígeno humano. El objetivo del trabajo fue determinar la transformación del Zineb a ETU en acelgas cultivadas en Jujuy, por efecto del calor húmedo por tratamiento térmico. El método se basó en la extracción de la ETU con agua y su posterior reextracción con diclorometano a pH alcalino. El extracto se purificó por cromatografía en columna de alúmina y la ETU se cuantificó por HPLC con un detector UV-Visible a 232 nm. Para cumplir con el objetivo planteado se realizó un cultivo experimental de acelgas a las que se aplicó el fungicida Zineb, el cual luego se cuantificó a diferentes periodos de tiempo. La ETU se cuantificó con y sin aplicación de calor húmedo. La concentración de ETU en las acelgas sometidas a tratamiento térmico fue de 8,07 mg/kg y transcurridos 30 días disminuyó a 0,05 mg/kg, lo que representa una disminución de más del 99 % respecto a la concentración inicial. Simultáneamente, se determinó la concentración de Zineb en las acelgas y se obtuvo, inicialmente, 44 mg/kg y luego de 36 días la concentración de Zineb disminuyó a 3,83 mg/kg, lo que representa una disminución del 91 % respecto a la concentración del plaguicida al inicio. La detección de ETU en acelgas sometidas a tratamientos térmicos confirma la transformación del fungicida Zineb a un producto de degradación clasificado según el IARC en el grupo 3. Esto pone en discusión la reglamentación Argentina vigente, por cuanto al finalizar los tiempos de carencia no se evalúan la presencia de metabolitos o productos de degradación potencialmente tóxicos.

Zineb is a pesticide belonging to the family of ethylenebisdithiocarbamates (EBDC) widely used in the province of Jujuy, Argentina. The toxicity of this fungicide is given by the ethylenethiourea (ETU) which is the main product of degradation. The ETU has mutagenic, teratogenic and carcinogenic effects in animals. The EPA classifies it as a probable human carcinogen. The aim of the study was to determine the transformation of Zineb to ETU in cultivated chards in Jujuy, by treatment with humid heat. The method is based on extraction of ETU with water and subsequent extraction of the aqueous phase with dichloromethane. The extract was cleaned by alumina column chromatography and the ETU was quantified by HPLC with a UV-Visible detector at 232 nm. An experimental cultivation of chards was carried out and the Zineb fungicide was applied and then quantified at different time periods. The ETU was quantified with and without application of moist heat. The concentration of ETU in heat treated chards was 8.07 mg/kg and after 30 days decreased to 0.05 mg/kg, representing a decrease of more than 99 % over the initial concentration. Simultaneously, Zineb concentration in chard was initially determined as 44 mg/kg and, 36 days later, the Zineb concentration decreased to 3.83 mg/kg, representing a 91% decrease with respect to the concentration of the pesticide at the beginning. Detection of ETU in chards subjected to heat treatment confirms the transformation of the fungicide Zineb to a degradation product classified by the IARC as group 3. This puts into discussion the current Argentine regulations since, at the end of the deficiency times the presence of potentially toxic metabolites or degradation products is not evaluated.

Effects of polymeric zinc propylen-bis-dithiocarbamate (propineb) on nasal mucosa in rats / Efectos de los polímeros del zinc propileno-bis-ditiocarbamato (propineb) en la mucosa nasal de ratas

The objective of this study was to evaluate the histopathologic and immunohistochemical effects of propineb on rat nasal mucosa. Twenty adult Sprague-Dawley rats weighing 180­220 g, were used as experimental animals. The rats were divided into propineb and control groups. The control group received distilled water with spray at the same time period. The experiment was terminated after three weeks. In each case, sections of the nosewere taken. In experimental group, microscopic examination of nasal respiratory mucosa revealed that degenerative changes in epithelium were observed in sections of propineb-treated group. There were also leukocyte infiltration and vascular dilatation detected in the connective tissue.We detected CD34-immunoreactive mononuclear cells and endothel cells in the lamina propria of propineb group. In propineb group compared to the control group, the respiratory epithelium, goblet and basal cell nuclei were stained positive for PCNA. Propineb inhalation may be irritating to the nasal mucosa.

El objetivo de este estudio fue evaluar los efecto histopatológicos e inmunohistoquímicos del Propineb en la mucosa nasal de 20 ratas Sprague-Dawley adultas con un peso de 180-220 g, las que fueron utilizadas como animales de experimentación. Las ratas se dividieron en grupos Propineb y Control. El grupo control recibió agua destilada en aerosol nasal en el mismo período de tiempo que el grupo Propineb. El experimento duró tres semanas. Posteriormente, en cada caso se tomaron muestras de la mucosa nasal. En el grupo experimental, tratado con Propineb, el examen microscópico de la mucosa respiratoria nasal reveló cambios degenerativos en el epitelio. Se detectó también infiltración de leucocitos y dilatación vascular en el tejido conectivo, junto con células mononucleares CD34 inmunorreactiva y células endoteliales en la lámina propia. En el grupo Propineb, en comparación con el grupo control, los núcleos de la porción respiratoria, las células caliciformes y basales resultaron positivas a la tinción del antígeno nuclear de proliferación celular (PCNA). La inhalación de Propineb puede ser un irritante para la mucosa nasal.

The effects of polymeric zinc propylen-bis-dithiocarbamate (Propineb) on tooth development in rats / Efectos del propileno-bis-ditiocarbamato de zinc polimérico (Propineb) sobre el desarrollo de los dientes en ratas

Dithiocarbamate propinebs are organometal fungicides that are widely used for the control of diseases in plants. In this study, pregnant female rats received 400 ppm propineb concentrations in 5 ml distilled water for 16 days of gestation, and then infant rats were obtained by cesarean section. In the histological analysis on the frontal sections, the use of propineb was found effective on odontoblast cell hyperplasia, cell infiltration in the dental papilla, and degeneration in the mesenchymal cells of the outer enamel. The expression of MMP-2 (Matrix Metalloproteinase-2) and VEGF (Endothelial cell growth factor) in the connective tissue was evaluated by immunohistochemistry. The drinking water given to the mothers in propineb tooth bud, enamel and dentin, resulted in morphological changes suggestive of a delay in formation, which cross the placental barrier and possibly affect the tooth development.

Los ditiocarbamatos (Propineb) son fungicidas organometálicos que son ampliamente utilizados para el control de enfermedades en las plantas. En este estudio, ratas hembras preñadas recibieron concentraciones de 4000 ppm de propineb en 5 ml de agua destilada durante 16 días de su gestación. Luego, las crías de las ratas fueron obtenidas mediante cesárea para su estudio estudio histológico. En el análisis histológico de las secciones frontales, el uso de propineb fue positivo para la hiperplasia de las células odontoblástica, infiltración de células en la papila dental, y la degeneración en las células mesenquimales del epitelio externo del esmalte. La expresión de MMP-2 (metaloproteinasa de la matriz 2) y VEGF (factor de crecimiento de células endoteliales) en el tejido conectivo se evaluó por inmunohistoquímica. El agua potable con propineb dada a las madres actuó sobre el brote dentario, esmalte y dentina; se tradujo en cambios morfológicos indicativos de un retraso en la formación. Por tanto, el propineb atraviesa la barrera placentaria y posiblemente afecten el desarrollo de los dientes.