Biochemical and estrogenic effects of N- (3,4-dichlorophenyl) -N, N-dimethylurea (diuron) and its metabolites, alone or in combination with alkylphenols in Nile tilapia (Oreochromis niloticus)

Author(s)

Andréia Arantes Felício

• Document type: Doctoral Thesis
• Press: São José do Rio Preto. 2017-03-29.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Biociências Letras e Ciências Exatas. São José do Rio Preto
• Defense date: 2017-02-21
• Advisor: Eduardo Alves de Almeida

Abstract

Brazil is the main sugar cane producer in the world, and to support these productions many chemical compounds have being apply in agriculture, aiming to control the appearance and proliferation of pests. Therefore, the use of pesticide, as diuron, (N- (3,4-dichlorophenyl) -N,N-dimethylurea), in some crops in the world is common. Diuron can be biodegraded in three others compounds, 3,4-dichloroaniline (DCA), 3,4-dichlorophenylurea (DCPU) and 2,4-dichlorophenyl-N-methylurea (DCPMU). Normally, diuron have being applied associated with alkylphenols ethoxylates (APE), like nonilphenol (NP) and octylphenol (OP), which increase the solubility and dispersion of the herbicide. Some studies have shown that diuron and alkylphenols can cause enzymatic and/or estrogenic changes, in various organisms. Therefore, biotransformation enzymes, phase I (7-ethoxirresorufin-O-deethylase – EROD, 7- pentaxirisorufin-O-dealkylase – PROD, 7-benzyloxysorufin-O-desalkylase – BROD and P450 aromatase), phase II (glutathione-S-transferase-GST) and phase III proteins (multixenobiotic resistance – MXR), and antioxidant parameters (superoxide dismutase – SOD, catalase – CAT, glutathione peroxidase – GPx, glutathione reductase – GR, glutathione-6-phosphate dehydrogenase – G6PDH, aldehyde dehydrogenase – ALDH and lipid peroxidation), which are responsible for the control between production and degradation of reactive oxygen species (ROS). The endocrine parameters that can be altered and used as biomarkers are the CYP3A and 17β-hydroxysteroid dehydrogenase (17β-HSD) enzymes and the vitellogenin (Vtg) protein. All of these parameters can be altered after exposure of organisms to xenobiotics. Therefore, the aim of this work was evaluate the effects of (1) diuron and its metabolites, alone or in combination, in different concentrations, and the effect of (2) diuron, its metabolites and the alkyphenols, alone or in combination, in different concentration, in liver and gill of Nile tilapia (Oreochromis niloticus) exposed for 7 days, using as parameters EROD, BROP, PROD, GST, MXR, SOD, CAT, GPx, G6PDH and lipid peroxidation (MDA). In a third step, the aim of the work as (3) evaluate endocrine parameters in mossambique tilapia (Oreochromis mossambicus), exposed to diuron, its metabolites and alkyphenols, alone or in combination, in different concentrations for 7 days, in liver and brain, using as parameters 17β-HSD, CYP3A, vitellogenin and xenobiotic biotransformation (in vitro). Our results demonstrated that all contaminants, at the concentration and time of exposure, can cause alteration in all biomarkers, some more than others, as EROD, MDA, GPx and G6PDH, in Nile tilapia, and the results obtained after mozambique tilapia exposure, to the contaminants, also showed changes, confirming that these compounds can be considered endocrine disruptors. Thus, the results showed that diuron, its metabolites and alkylphenols could cause biochemical changes in fish, Nile and mossambique tilapia, exposing to the environmentally relevant concentrations for seven days, being diruon metabolites and APs the main compounds to cause changes in the analyzed parameters. (AU)

• FAPESP's process: 14/18825-9 - Estrogenic and biochemical effects of N-(3,4-dichlorophenyl)-N, N-dimethylurea (diuron) and its metabolites, alone or in combination with alkylphenols in Nile Tilapia (Oreochromis niloticus)
• Grantee: Andréia Arantes Felício
• Support Opportunities: Scholarships in Brazil - Doctorate