RESUMEN
The influence of temperature (25 and 32 °C) on the biomarker responses of bullfrog tadpoles (Lithobates catesbeianus) to different concentrations of the atrazine metabolite 2-hydroxyatrazine (2-HA, 0, 10, 50 and 200 ng.L-1, 16 days), was evaluated. Temperature affected the activities of superoxide dismutase, glutathione S-transferase and acetylcholinesterase. The activities of catalase, glutathione peroxidase, glucose-6-phosphate dehydrogenase and carboxylesterase presented no alterations. Frequencies of micronuclei and nuclear abnormalities were also not altered. 2-HA decreased SOD activity at 25 °C and caused histopathological changes in the liver and the kidney at both temperatures, with the kidney being more affected by the combination of higher temperature and 2-HA exposure, presenting glomerular shrinkage and an increase in Bowman's space. Our results indicate that at environmentally relevant concentrations, 2-HA can cause changes in biomarker responses as well as in the morphology of liver and kidney in L. catesbeianus tadpoles. Temperature has an important influence on biomarker response and histopathological alterations.
Asunto(s)
Atrazina , Contaminantes Químicos del Agua , Animales , Rana catesbeiana , Atrazina/metabolismo , Larva/metabolismo , Temperatura , Acetilcolinesterasa/metabolismo , Contaminantes Químicos del Agua/toxicidad , Biomarcadores/metabolismoRESUMEN
The S-triazine herbicide ametryn (AMT) is relatively low adsorbed in soils and has high solubility in water, thus believed to affect non-target aquatic organisms such as amphibians. Temperature increases can intensify the effects of herbicides, possibly increasing the susceptibility of amphibians to these compounds. The aim of this study was to evaluate the influence of temperature (25 and 32 °C) on the responses of biochemical biomarkers in bullfrog tadpoles (Lithobates catesbeianus) exposed to different concentrations of AMT (0, 10, 50 and 200 ng.L-1) for a period of 16 days. The antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) and the biotransformation enzyme glutathione S-transferase (GST) had their activity decreased at the highest temperature (32 °C). SOD activity was reduced at 200 ng.L-1 and 32 °C compared to the control at the same temperature. AMT exposure also decreased the activities of alanine aminotransferase and gamma glutamyl transferase. On the other hand, the activities of acetylcholinesterase, carboxylesterase, alkaline phosphatase, levels of lipid peroxidation and protein carbonyl, as well genotoxic markers (micronucleus and nuclear abnormalities frequencies) were unchanged. The evaluation of integrated biomarker response index (IBR) indicated highest variations at the concentration of 200 ng.L-1 at 32 °C, suggesting that the combination of high AMT concentrations and temperatures generate more pronounced negative effects to tadpoles.
Asunto(s)
Herbicidas , Contaminantes Químicos del Agua , Acetilcolinesterasa/metabolismo , Alanina Transaminasa/metabolismo , Fosfatasa Alcalina/metabolismo , Animales , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Catalasa/metabolismo , Glutatión Transferasa/metabolismo , Herbicidas/metabolismo , Larva , Rana catesbeiana/metabolismo , Suelo , Superóxido Dismutasa/metabolismo , Temperatura , Triazinas/metabolismo , Agua/metabolismo , Contaminantes Químicos del Agua/metabolismoRESUMEN
The influence of temperature (25 and 32 °C) on the negative effects of the herbicide tebuthiuron (TBU, 0, 10, 50 and 200 ng.L-1, 16 days) on thyroid function and metamorphosis of Lithobates catesbeianus tadpoles was evaluated. Metamorphosis was accelerated by TBU exposure at 25 ºC, but delayed at 32 ºC with considerable losses of body mass. T3 and T4 levels were not altered. The highest TBU concentrarion at 25 ºC increased TRâ¯ß and DIO3 transcript levels, which is consistent with development acceleration in tadpoles. At 32 ºC TRâ¯ß transcript levels were lower than the values recorded at 25 ºC, and those tadpoles exposed to the highest TBU concentration presented increased diameter of thyroid follicles compared to controls at same temperature. This study evidences that TBU at environmentally realistic concentrations is able to disrupt thyroidogenesis in bullfrog tadpoles, impairing their development. These effects are influenced by temperature.
Asunto(s)
Herbicidas , Animales , Herbicidas/metabolismo , Herbicidas/toxicidad , Larva , Metamorfosis Biológica , Compuestos de Metilurea , Rana catesbeiana , Temperatura , Glándula Tiroides , Receptores beta de Hormona TiroideaRESUMEN
Tebuthiuron (TBU) is a phenylurea herbicide that is extensively used in sugarcane fields. Owing to the low degradation rate, high water solubility, and leaching potential, TBU is believed to have harmful effects on aquatic organisms, such as anuran tadpoles. Contaminant effects can be influenced by temperature since increases in temperature are often associated with increased metabolic reactions. In this study, we evaluated the influence of temperature on the negative effects of TBU in bullfrog tadpoles (Lithobates catesbeianus) through a multi-biomarker approach. Tadpoles were exposed to 0 (control) 10, 50, and 200 ng L-1 of TBU for 16 days at 25 and 32 °C. TBU increased the transcript levels of genes involved in biotransformation (glutathione S-transferase, GST, and sulfotransferase, SULT) and antioxidant (superoxide dismutase, SOD, and catalase, CAT) enzymes. TBU exposure also increased CAT and glutathione peroxidase (GPx) activities, whereas SOD and carboxylesterase activities were decreased. The highest temperature caused a decrease in the activities of ethoxyresorufin-O-deethylase and SOD but increased the activities of GST, GPx, glucose 6-phosphate dehydrogenase, and acetylcholinesterase. No effects of temperature or TBU exposure were observed in genotoxic markers (frequencies of micronucleous and nuclear abnormalities) or in lipid peroxidation levels. Tadpoles exposed to TBU at all tested concentrations presented a higher index of biomarker responses than that of the control groups. Higher values of severity scores from histological analyses were found in the liver of tadpoles exposed to 50 and 200 ng L-1 of TBU at 32 °C compared with those of the control group at the same temperature. These results indicate that TBU and temperature increases are able to disturb the metabolic homeostasis of L. catesbeianus tadpoles after 16 days of exposure, causing substantial alterations in biomarker responses and liver morphology.
Asunto(s)
Herbicidas , Contaminantes Químicos del Agua , Animales , Biomarcadores , Herbicidas/toxicidad , Larva , Hígado , Compuestos de Metilurea , Rana catesbeiana , Temperatura , Estados Unidos , Contaminantes Químicos del Agua/toxicidadRESUMEN
Vitiligo is a chronic illness of a yet unknown etiology, characterized by an acquired and progressive depigmentation of the skin. There are diverse treatments for this condition around the world, but up to now, none has been completely effective. The objective of this work was to evaluate the application of an antioxidant and mitochondrial stimulating formula, of topic use in leukodermic areas of patients with stable vulgar vitiligo. A clinical, experimental, randomized, double blind study was carried out in 50 male and 50 female patients with stable vulgar vitiligo. The patients were distributed in five groups as follows: Group 1 (labelled as VitilVenz AF): application of antioxidant and mitochondrial stimulating cream and oral administration of antioxidants and phenylalanine. Group 2 (labelled as Placebo AF): application of a placebo cream and oral administration of antioxidants and phenylalanine. Group 3 (labelled as without cream AF): oral administration of antioxidants and phenylalanine. Group 4 (labelled as Placebo cream): application of a placebo cream. Group 5 (labelled as VitilVenz): application of the antioxidant and mitochondrial stimulating cream. The following were measured in all patients: the clinical area of newly formed pigment every 30 days, during five months; and the presence of melanocytes in the histological study, at the beginning and at the end of treatment. The test of multiple comparison of Turkey-Kramer was used for the analysis of the results. The scheme of treatment that produced the best results was that of the Group 1, which consisted of the joint application of the antioxidant and mitochondrial stimulating cream and oral administration of antioxidants and phenylalanine (p < 0.001); followed by Group 5 that only received the topical treatment with the antioxidant and mitochondrial stimulating cream. The clinical and histological responses of these two groups (1 and 5) were significantly different to the rest of the groups. We concluded that the melanocytes in these patients could be in a dysfunctional state, product of the formation of free radicals that cause cellular and mitochondrial toxicity; and that these free radicals are removed by the antioxidant and mitochondrial stimulating elements present in the cream, turning the melanocytes functional and producing melanin in the achromic area of the vitiligo. This effect would be potentiated by the use of oral antioxidants and phenylalanine.
Asunto(s)
Antioxidantes/uso terapéutico , Mitocondrias/efectos de los fármacos , Fenilalanina/uso terapéutico , Preparaciones de Plantas/uso terapéutico , Vitíligo/tratamiento farmacológico , Administración Cutánea , Administración Oral , Antioxidantes/administración & dosificación , Antioxidantes/farmacología , Método Doble Ciego , Femenino , Depuradores de Radicales Libres/administración & dosificación , Depuradores de Radicales Libres/farmacología , Depuradores de Radicales Libres/uso terapéutico , Humanos , Masculino , Melanocitos/efectos de los fármacos , Melanocitos/metabolismo , Melanocitos/patología , Minerales/administración & dosificación , Minerales/uso terapéutico , Pomadas , Estrés Oxidativo/efectos de los fármacos , Fenilalanina/administración & dosificación , Preparaciones de Plantas/administración & dosificación , Preparaciones de Plantas/farmacología , Piel/efectos de los fármacos , Piel/patología , Pigmentación de la Piel/efectos de los fármacos , Vitaminas/administración & dosificación , Vitaminas/uso terapéutico , Vitíligo/patologíaRESUMEN
El vitiligo es una enfermedad crónica, despigmentante de la piel, de carácter progresivo y adquirido, con etiología aún desconocida. Existen diversos tratamientos en el mundo, pero hasta ahora ninguno ha sido totalmente efectivo. El objetivo de este trabajo fue evaluar la aplicación de una formulación antioxidante y estimulante mitocondrial de uso tópico, en zonas leucodérmicas de pacientes con vitiligo vulgar estable. Se realizó un ensayo clínico, experimental, aleatorizado y doble ciego en 100 pacientes con vitiligo vulgar estable, 50 varones y 50 mujeres, distribuidos en cinco grupos, a saber: Grupo 1 (etiquetado como VitilVenz AF): Aplicación de crema antioxidante y estimulante mitocondrial e ingestión oral de antioxidantes y fenilalanina. Grupo 2 (etiquetado como Placebo AF): Aplicación de crema con placebo e ingestión oral de antioxidantes y fenilalanina. Grupo 3 (etiquetado como sin crema AF): Ingestión oral de antioxidantes y fenilalanina. Grupo 4 (etiquetado como crema Placebo): Aplicación de crema placebo. Grupo 5: (etiquetado como Vitilvenz): Aplicación de crema antioxidante y estimulante mitocondrial. En todos los pacientes se midieron: la zona clínica de pigmento formado cada 30 días y durante cinco meses y la presencia de melanocitos en el estudio histológico al inicio del estudio y al final del tratamiento. Para el análisis de los resultados se utilizó la prueba de comparación múltiple de Tukey-Kramer. El mejor esquema de tratamiento y que produjo mejores resultados fue el del grupo 1 basado en la ingestión de antioxidantes y fenilalanina conjuntamente con la aplicación de la crema antioxidante y estimulante mitocondr¡al (p < 0,001), seguido por el grupo 5 que recibió tratamiento tópico con la crema antioxidante y estimulante mitocondrial. La respuesta clínica e histológica de estos dos grupos (1 y 5) fue significativamente diferente al resto de los grupos 2, 3 y 4.