DNA damage and oxidative stress in gill cells of Cnesterodon decemmaculatus exposed to pesticides by runoff source in an agricultural basin.

In our country, great concern exists about diffuse pollution cause by the great use of pesticides in rural environments. A thorough analysis is needed to generate information, know the real situation and thus, be able to make decisions with the purpose of reducing environmental pollution. In situ bioassays have been carried out using Cnesterodon decemmaculatus within limnocorrals located in a surface natural water system that receives rainfall excess flowing from an agricultural basin with a typical crop rotation, including corn, wheat and soy. Specimens were taken from the limnocorrals 72 h after a probed natural runoff event toward the water body, and the gill cells were used to evaluate the DNA damage (comet assay, CA), catalase enzyme activity (CAT), and lipid peroxidation (LPO). In addition, the physicochemical analysis of the water (pH, temperature) and the presence and concentration of pesticides were carried out. The results showed significant differences on DNA damage and oxidative stress on the gill cells of the exposed fish compared to controls, being the combination of the rain regime and the mixtures of pesticides used in corn and soy more toxic than in wheat. These results highlight the necessity to understand detrimental processes caused by pesticides used in extensive systems of primary production, in order to prevent and minimize diffuse contamination, contributing to environmental recovery and sustainability.

Modulator effect of watercress against cyclophosphamide-induced oxidative stress in mice.

Watercress (Nasturtium officinale, Cruciferae; W. Aiton) is a vegetable widely consumed in our country, with nutritional and potentially chemopreventive properties. Previous reports from our laboratory demonstrated the protective effect of watercress juice against DNA damage induced by cyclophosphamide in vivo. In this study, we evaluated the in vivo effect of cress plant on the oxidative stress in mice. Animals were treated by gavage with different doses of watercress juice (0.5 and 1g/kg body weight) for 15 consecutive days before intraperitoneal injection of cyclophosphamide (100 mg/kg body weight). After 24 h, mice were killed by cervical dislocation. The effect of watercress was investigated by assessing the following oxidative stress biomarkers: catalase activity, superoxide dismutase activity, lipid peroxidation, and glutathione balance. Intake of watercress prior to cyclophosphamide administration enhanced superoxide dismutase activity in erythrocytes with no effect on catalase activity. In bone marrow and liver tissues, watercress juice counteracted the effect of cyclophosphamide. Glutathione balance rose by watercress supplementation and lipid oxidation diminished in all matrixes when compared to the respective control groups. Our results support the role of watercress as a diet component with promising properties to be used as health promoter or protective agent against oxidative damage.

Modulator effect of watercress against cyclophosphamide-induced oxidative stress in mice

Watercress (Nasturtium officinale, Cruciferae; W. Aiton) is a vegetable widely consumed in our country, with nutritional and potentially chemopreventive properties. Previous reports from our laboratory demonstrated the protective effect of watercress juice against DNA damage induced by cyclophosphamide in vivo. In this study, we evaluated the in vivo effect of cress plant on the oxidative stress in mice. Animals were treated by gavage with different doses of watercress juice (0.5 and 1g/kg body weight) for 15 consecutive days before intraperitoneal injection of cyclophosphamide (100 mg/kg body weight). After 24 h, mice were killed by cervical dislocation. The effect of watercress was investigated by assessing the following oxidative stress biomarkers: catalase activity, superoxide dismutase activity, lipid peroxidation, and glutathione balance. Intake of watercress prior to cyclophosphamide administration enhanced superoxide dismutase activity in erythrocytes with no effect on catalase activity. In bone marrow and liver tissues, watercress juice counteracted the effect of cyclophosphamide. Glutathione balance rose by watercress supplementation and lipid oxidation diminished in all matrixes when compared to the respective control groups. Our results support the role of watercress as a diet component with promising properties to be used as health promoter or protective agent against oxidative damage.

El berro (Nasturtium officinale, crucíferas; W. Aiton) es una hortaliza ampliamente consumida en nuestro país, con valor nutricional y propiedades potencialmente quimiopreventivas. En trabajos previos demostramos que el jugo de berro tiene efecto protector in vivo contra el daño del ADN inducido por ciclofosfamida en tejidos del ratón. En el presente trabajo evaluamos, también in vivo, los efectos del jugo sobre el estrés oxidativo en diferentes tejidos del ratón. Los siguientes biomarcadores fueron investigados: actividad de superóxido dismutasa, actividad de catalasa, peroxidación lipídica y balance de glutatión. Los animales fueron tratados con diferentes dosis de jugo (0.5 y 1 g/kg de peso corporal) por alimentación forzada durante 15 días consecutivos antes de la inyección intraperitoneal con ciclofosfamida (100 mg/kg). La ingesta de berro antes de la administración de ciclofosfamida mejoró la actividad de superóxido dismutasa en los eritrocitos sin efecto sobre la actividad de la catalasa. En médula ósea e hígado, el jugo de berro contrarrestó el efecto deletéreo de la ciclofosfamida. En todas las matrices, el balance de glutatión fue mayor y la oxidación de lípidos menor que los valores encontrados en los grupos control. Nuestros resultados demuestran que el berro es un componente de la dieta con propiedades prometedoras como promotor de la salud o como agente protector contra el daño oxidativo.

Evaluation of Stage-Dependent Genotoxic Effect of Roundup® (Glyphosate) on Caiman latirostris Embryos.

The agricultural expansion over the past decades, along with the associated increase in the use of pesticides, represents a high risk for many wild species. Caiman latirostris is a South American caiman with many features that make it highly vulnerable to pesticide exposure. Considering previous finding on the genotoxicity of the glyphosate-based formulation Roundup® in this species, the aim of this study was to evaluate the possible stage-dependent effect of this compound on C. latirostris embryos through the Comet assay (CA), micronuclei (MN), and nuclear abnormalities (NA) tests. Caiman eggs were exposed to three effective concentrations of Roundup® (750, 1250, 1750 µg/egg) in three different stages of the incubation period (total duration 70 ± 3 days at 31 ± 2 °C) of approximately 23 days each. A statistically significant difference in DNA damage determined by the CA was found between groups exposed to different concentrations of RU (p < 0.05) and the negative control, but no difference was observed among the three stages of exposure within any treatment (p > 0.05). There was no differences in the MN or NA frequencies between the different groups and the negative control (p > 0.05), nor among the different stages within each treatment. The results obtained in this study indicate that RU produce DNA damage on C. latirostris embryos independently of the developmental stage where the exposure occurs, implying an important risk for the species during all its period of development, when pesticide application is at maximum rate.

Biomarkers of oxidative damage and antioxidant defense capacity in Caiman latirostris blood.

Several xenobiotics, and among them pesticides, can produce oxidative stress, providing a mechanistic basis for their observed toxicity. Chronic oxidative stress induces deleterious modifications to DNA, lipids and proteins that are used as effective biomarkers to study pollutant-mediated oxidative stress. No previous report existed on the application of oxidative damage and antioxidant defense biomarkers in Caiman latirostris blood, while few studies reported in other crocodilians were done in organs or muscles of dead animals. The aim of this study was to characterize a new set of oxidative stress biomarkers in C. latirostris blood, through the modification of conventional techniques: 1) damage to lipids by thiobarbituric acid reactive substances (TBARS), 2) damage to DNA by comet assay modified with the enzymes FPG and Endo III, and 3) antioxidant defenses: catalase, superoxide dismutase and glutathione; in order to apply them in future biomonitoring studies. We successfully adapted standard procedures for CAT, SOD, GSH and TBARS determination in C. latirostris blood. Calibration curves for FPG and Endo III showed that the three dilutions tested were appropriate to conduct the modified comet assay for the detection of oxidized bases in C. latirostris erythrocytes. One hour of incubation allowed a complete repair of the damage generated. The incorporation of these biomarkers in biomonitoring studies of caiman populations exposed to xenobiotics is highly important considering that this species has recovered from a serious endangered state through the implementation of sustainable use programs in Argentina, and represents nowadays a relevant economic resource for many human communities.

Neurologic dysfunction and genotoxicity induced by low levels of chlorpyrifos.

Chlorpyrifos (CPF) is an organophosphorus cholinesterase inhibitor widely used as an insecticide. Neuro and genotoxicity of this agent were evaluated following daily subcutaneous injections at 0.1, 1 and 10mg/kg or its vehicle to laboratory rats during one week, at the end of which somatosensory evoked potentials (SEP) and power spectrum of the electroencephalogram (EEGp) were recorded under urethane anesthesia. In another group of conscious animals, auditory startle reflex (ASR) was evaluated followed, after euthanasia, with measurements of plasma B-esterases, and genotoxicity with the alkaline comet assay (ACA) at the same CPF doses. The results indicated a CPF dose related inhibition of B-esterases. Enhanced inhibition of the ASR by a subthreshold pre-pulse was observed at all doses and ACA showed a significant higher DNA damage than vehicle controls in animals exposed to 10mg/kg CPF. A trend to higher frequencies of EEGp and an increase in amplitude of the first negative wave of the SEP were found at all doses. The first positive wave of the SEP decreased at the CPF dose of 10mg/kg. In summary, a shift to higher EEG frequencies and alterations of somatosensory and auditory input to the central nervous system were sensitive manifestations of CPF toxicity, associated with depression of B-esterases. The changes in electrical activity of the cerebral cortex and DNA damage observed at doses that do not elicit overt toxicity may be useful in the detection of CPF exposure before clinical signs appear.

Assessment of oxidative status and genotoxicity in photocopier operators: a pilot study.

Occupational exposure to photocopiers has been indicated as being responsible for a number of health complaints, particularly effects on the respiratory, immunological, and nervous systems. In this study, we investigated oxidative and genotoxic damage in photocopier operators by assessing catalase activity (CAT), reduced vs. oxidized glutathione ratio (GSH/GSSG), level of lipid peroxidation (TBARS), damage index by Comet assay (DICA), and buccal cells with micronuclei (BCMN). Our results reveal that the TBARS levels in operators were increased (27%; p<0.05) but that no significant alterations to GSH/GSSG or CAT activity were observed. The DICA and the number of BCMN were significantly increased (134% and 100%, respectively; p<0.05) in the exposed group. There was a significant association between the time in months spent at work and DNA damage in lymphocytes (r(s) = 0.720; p<0.001) and buccal cell with MN (r(s) = 0.538; p<0.001). Because laser printers and photocopiers have become increasingly used, it is important to control human exposure using reliable biomarkers.

[Biochemical evaluation on rural workers exposed to pesticides]. / Evaluación bioquímica de trabajadores rurales expuestos a pesticidas.

Pesticides are used in agriculture to protect crops but may represent a potential risk to farmers and the environment. The aim of this work was to evaluate horticultural workers exposed to pesticide, categorized by: direct exposure (n = 45), indirect exposure (n = 50) and controls (n = 50) using exposure and effect biomarkers: cholinesterase (ChE), acetylcholinesterase (AChE), catalase (CAT), lipid peroxidation (TBARS), Damage Index Comet Assay (IDEC) and Damage Index Repair Assay (IDER). Our results show: a) an AChE inhibition in directly and indirectly exposed population (p < 0.001), b) significant increase in the levels of TBARS in direct exposure (p < 0.001), c) the CAT reduction was significant (p < 0.01), d) a significant increase in IDEC and IDER in both exposed groups (p < 0.001). Our results evidence variations in oxidative balance and DNA damage in exposed workers. These findings represent a contribution to the sub-clinical evaluation of subjects exposed to agrochemicals in our country.

Evaluación bioquímica de trabajadores rurales expuestos a pesticidas / Biochemical evaluation on rural workers exposed to pesticides

Los pesticidas utilizados en agricultura pueden representar un riesgo potencial para la salud de los agricultores expuestos y para el medio ambiente. El objetivo de este trabajo fue evaluar trabajadores frutihortícolas expuestos a plaguicidas, categorizados por: exposición directa (n = 45), exposición indirecta (n = 50) y controles (n = 50) mediante biomarcadores de exposición y efecto: colinesterasa (ChE), acetilcolinesterasa (AChE), catalasa (CAT), peroxidación de lípidos (TBARS), Indice de Daño Ensayo Cometa (IDEC) e Indice de Daño Ensayo Reparación (IDER). Los resultados indican: a) inhibición significativa de AChE (p < 0.001) en expuestos directos e indirectos; b) aumento en los niveles de TBARS (p < 0.001) en los directos; c) reducción de CAT significativa (p < 0.01) y d) aumento de IDEC e IDER (p < 0.001) en ambos grupos. Los resultados obtenidos reflejan modificaciones en el balance oxidativo junto con daño al ADN en los trabajadores estudiados. Estos hallazgos representan una contribución en la evaluación subclínica de exposición a agroquímicos en nuestro país.

Pesticides are used in agriculture to protect crops but may represent a potential risk to farmers and the environment. The aim of this work was to evaluate horticultural workers exposed to pesticide, categorized by: direct exposure (n = 45), indirect exposure (n = 50) and controls (n = 50) using exposure and effect biomarkers: cholinesterase (ChE), acetylcholinesterase (AChE), catalase (CAT), lipid peroxidation (TBARS), Damage Index Comet Assay (IDEC) and Damage Index Repair Assay (IDER). Our results show: a) an AChE inhibition in directly and indirectly exposed population (p < 0.001), b) significant increase in the levels of TBARS in direct exposure (p < 0.001), c) the CAT reduction was significant (p < 0.01), d) a significant increase in IDEC and IDER in both exposed groups (p < 0.001). Our results evidence variations in oxidative balance and DNA damage in exposed workers. These findings represent a contribution to the sub-clinical evaluation of subjects exposed to agrochemicals in our country.

Biomarkers of cellular reaction to pesticide exposure in a rural population.

In the present study we report data obtained from the evaluation of subjects occupationally exposed to pesticide mixtures from Santa Fe province, Argentina, using biomarkers for butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) activities, catalase (CAT), lipid peroxidation (by TBARS assay) and the Damage Index Comet Assay (DICA). Our results showed an AChE inhibition (25% and 15% in directly and indirectly groups, respectively) in relation to controls with no significant modifications in BChE. TBARS levels were higher (51%) in pesticide sprayers while CAT activity was reduced in both, applicators (61%) and non-applicators (43%). DICA was significantly increased in direct (83%) and indirect (98%) exposed groups, compared with controls. These results showed modifications in lipid peroxidation, antioxidant defence system, and DNA damage in lymphocytes of exposed workers. Further investigations are suggested in order to link our findings with adverse health effects observed in chronic pesticide toxicity, where oxidative damage plays a pathophysiological role.