RESUMO
Nervous and immune systems maintain a bidirectional communication, expressing receptors for neurotransmitters and cytokines. Despite being well established in mammals, this has been poorly described in lower vertebrates as fishes. Experimental evidence shows that the neurotransmitter acetylcholine (ACh) regulates the immune response. In this research, we evaluated mRNA levels of muscarinic acetylcholine receptor (mAChR) in spleen mononuclear cells of Nile tilapia (Oreochromis niloticus) and compared the expression levels of immune cells with the brain. The mAChR subtypes (M2-M5A) were detected in both tissues, but mAChRs mRNA levels were higher in immune cells. This data have a potential use in biomedical and comparative immunology fields.
Assuntos
Encéfalo/imunologia , Ciclídeos/imunologia , Leucócitos Mononucleares/imunologia , Receptores Muscarínicos/biossíntese , Animais , Encéfalo/metabolismo , Ciclídeos/metabolismo , Proteínas de Peixes/biossíntese , Proteínas de Peixes/imunologia , Leucócitos Mononucleares/metabolismoRESUMO
Organophosphorus pesticides (OPs) are broad-spectrum insecticides. One of the commonly used OPs is diazinon (DZN). The aim of this study was to evaluate the immunotoxic effect of DZN on phagocytic parameters of blood leukocytes using the teleost fish Oreochromis niloticus as a study model. For this purpose, fish were exposed in vivo to 0.97, 1.95 and 3.97â¯mg/L of DZN for 6 and 24â¯h. Our results indicated that phagocytic active cells decreased in fish exposed in vivo to 0.97 and 1.95â¯mg/L of DZN for 6 and 24â¯h. Regarding ROS production, H2O2 and O2- levels were higher on fish exposed to 1.95â¯mg/L for 6 and 24â¯h, while H2O2 production increased at 0.97â¯mg/L for 24â¯h. From this we can conclude that phagocytic parameters are sensitive to assess the effect of acute intoxication with organophosphorus pesticides on Nile tilapia.
Assuntos
Ciclídeos/fisiologia , Diazinon/efeitos adversos , Inseticidas/efeitos adversos , Leucócitos/efeitos dos fármacos , Fagocitose/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Explosão Respiratória/efeitos dos fármacos , Animais , Biomarcadores/sangue , Ciclídeos/imunologia , Leucócitos/fisiologia , Masculino , Poluentes Químicos da Água/efeitos adversosRESUMO
Fish rearing under intensive farming conditions can be easily disturbed by pesticides, substances that have immunotoxic properties and may predispose to infections. Organophosphorus pesticides (OPs) are widely used in agricultural activities; however, the mechanism of immunotoxicity of these substances is unclear. The aim of this study was to evaluate the effect of diazinon pesticides (OPs) on the cholinergic system of immune cells as a possible target of OP immunotoxicity. We evaluated ACh levels and cholinergic (nicotinic and muscarinic) receptor concentration. Additionally, AChE activity was evaluated in mononuclear cells of Nile tilapia (Oreochromis niloticus), a freshwater fish mostly cultivated in tropical regions around the world. The obtained results indicate that acute exposure to diazinon induces an increase in ACh concentration and a decrease in nAChR and mAChR concentrations and AChE activity in fish immune cells, This suggests that the non-neuronal lymphocytic cholinergic system may be the main target in the mechanism of OP immunotoxicity. This study contributes to the understanding of the mechanisms of immunotoxicity of pollutants and may help to take actions for animal health improvement.
Assuntos
Ciclídeos/imunologia , Diazinon/toxicidade , Inseticidas/toxicidade , Linfócitos/efeitos dos fármacos , Sistema Nervoso Parassimpático/efeitos dos fármacos , Acetilcolina/análise , Acetilcolinesterase/metabolismo , Animais , Masculino , Receptores Colinérgicos/análise , Receptores Colinérgicos/efeitos dos fármacosRESUMO
Boca de Camichin Estuary is one of the main producers of Crassostrea corteziensis oysters in Mexico, but the presence of pollutants can affect oyster production. Molluscs produce reactive oxygen species (ROS) in response to changes in the environment and pollution. These ROS induce oxidative damage in biomolecules. The main objective of this study was to evaluate pollution in the estuary and the subsequent oxidative stress in C. corteziensis oysters during the 2010 production cycle. For this aim, we performed monthly samplings in the oyster farms from January to May. We took water samples to quantify polycyclic aromatic hydrocarbon (PAH) and metal content; also, we evaluated oxidative damage (lipoperoxidation, lipidic hydroperoxides, protein oxidation) and enzyme activity (CAT, SOD, GPx, GST and AChE) in oyster gills. The results show the presence of Cu, Fe, Mn, naphthalene, benz[a]anthracene, pyrene, benz[a]pyrene and benzo[k]fluoranthene. On the other hand, AChE activity was not inhibited, which suggests that organophosphorus pollutants or carbamates were absent. Regarding oxidative stress, oysters from the estuary had oxidative damage in lipids, not proteins, and altered antioxidant enzyme activity, when compared to control organisms. Interestingly, we did not observe any correlation between the pollutants and the oxidative stress parameters evaluated in this study. Thus, we cannot rule out that a synergistic effect between the environmental variables and the pollutants is causing the oxidative stress in these oysters.
Assuntos
Crassostrea/metabolismo , Estuários , Estresse Oxidativo , Poluentes Químicos da Água/metabolismo , Poluição da Água/análise , Acetilcolinesterase/metabolismo , Animais , Catalase/metabolismo , Cobre/metabolismo , Cobre/toxicidade , Crassostrea/efeitos dos fármacos , Monitoramento Ambiental/métodos , Geografia , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Glutationa Peroxidase/metabolismo , Ferro/metabolismo , Peróxidos Lipídicos/metabolismo , Manganês/metabolismo , Manganês/toxicidade , Metais/metabolismo , Metais/toxicidade , México , Naftalenos/metabolismo , Naftalenos/toxicidade , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Espécies Reativas de Oxigênio/metabolismo , Estações do Ano , Superóxido Dismutase/metabolismo , Poluentes Químicos da Água/toxicidadeRESUMO
Immune response is modulated by different substances that are present in the environment. Nevertheless, some of these may cause an immunotoxic effect. In this paper, the effect of organophosphorus pesticides (frequent substances spilled in aquatic ecosystems) on the immune system of fishes and in immunotoxicology is reviewed. Furthermore, some cellular and molecular mechanisms that might be involved in immunoregulation mechanisms of organophosphorus pesticides are discussed.