Disrupção endócrina em testículos de Poecilia reticulata causada pelo herbicida glifosato

• Autor(a) principal: Pires, Fernando Santiago
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/001300000233r
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/3846
• topic: Reprodução; Peixes; Disruptores endócrinos; Agrotóxicos; Reproduction; Fish; Endocrine disrupter; Agrotoxics; BIOQUIMICA::BIOLOGIA MOLECULAR

Xenobiotics pesticides are widely used in crops or even gardening throughout the world with purpose of a broad spectrum pest control, herbicides with glyphosate (N- phosphonomethyl glycine) as an active ingredient stands out amongst that group. The glyphosate (GLI) participates in a unique metabolic pathway during the synthesis of amino acids in plants, although, in animals it was thought to be harmless. However, literature indicates toxicity from commercial solutions, but few studies done with pure GLI. Moreover, to verify toxic potential of GLI, experiments done using Nuclear Magnetic Resonance (NMR). Furthermore, the test tanks were examined the presence of GLI for a period of 96 hours. It is because the GLI, during the metabolism of prokaryotes, converts to Aminomethylphosphonic acid (AMPA). The results showed the absence of AMPA at 96 hours of exposure, whereas, any changes were attributed to GLI in these animals. Primarily, the dose of CL50-96h for the experimental animal, Poecilia reticulata (guppy), was determined. It estimated at 68.51 ± 2.2 mg/L for males and at 70.56 ± 2.96 mg/L for females. The lethal dose calculated according to the recommended guidelines from the Organisation for Economic Co-operation and Development (OECD). During these tests the animals in the experimental group (EG) exposed at concentrations of 50, 55, 60.5, 66.5 and 73.2 mg/L showed swimming changes (17.5% - lethargy, 11.1 % - irregular swimming and 45.9% - hypoxia). Respiratory changes (8.3% - swam to the tank surface, 1.8% - hypo oxygenated) and changes in color pattern, such as loss of intensity of the hues orange, red, blue, and assuming a dull coloration (14.3%) in all EG. Subsequently, male’s guppy treated with sublethal doses of pure GLI in concentrations of 17.13 mg/L (25% CL50), 34.26 mg/L (50% CL50) and 51.39 mg/L (75% CL50) as per 203 guidelines of the OECD. After euthanasia, by descerebration, the male animals were dissected and the testicles fixed in buffered paraformaldehyde, sectioned in 2.0 μm slices by an ultramicrotome and placed in histoResin®. The sections stained with hematoxylin and toluidine blue/Floxine B, then photographed under light microscope. The program Image-Pro Plus provided the images, which analyzed by the program Statistica 7.0. Consequently, the data reviewed that GLI has toxic potential. It has the potential to: cause testicular regression - morphometric measures decrease, reduce the number of the spermatic compartments, reduce the gonad index (Igs) and promote histopathology which may lead to reduction or loss of function. Thus, characterizing a process of demasculinization, which indicates endocrine disruption.