Dimorfismo sexual de camundongos expostos na puberdade ou na idade adulta ao glifosato – ROUNDUP®: estudos em modelos comportamentais

Resumo (EN)

Glyphosate is a non-selective, broad-spectrum, post-emergence herbicide. lt is used to control weeds in emerged grasses, broad-leaf weeds, pastures and rice, com and soy plantations. This herbicide is considered one of most important pollutants of water and soil. lts presence in the food chain suggests that animals as well humans may be exposed to this pesticide. Several evidences indicate that glyphosate and its commercial formulations have endocrine disruptor properties. The main objective of the present study was to investigate, in mice, the sexual dimorphic behavioral effects of a glyphosate commercial formulation (GFR) after acute or long­term exposure. The acute studies were performed in adult age and the long-term treatment was done during puberty. The animal models employed were the general activity in an open field test (CA), the anxiety-like effects evaluated in an elevated plus maze (LCE) and the depressive-like effects in the Porsolt test (TNF). Male (MC) and female (CF) adult mice and 23 days old mice were employed in these studies. The GFR time and dose effects (25, 50 and 100mgKg-1) were investigated in male adult mice. The acute toxicity signs after 100 mgKg-1 were observed during 60 min in MC and FC. Since the GFR peak of effects were detected 15 min after exposure to the pesticide, the acute behavioral tests (CA, LCE and TNF) were performed at this time. ln the long-term treatment, the GFR (50 mgKg-1 was given orally daily from 23 days old mice until 45 days of age; the experiments performed 1 O days after the treatment withdrawn. Results showed that the latency to effects of GFR different doses was 15 min. ln the toxicity tests the GFR administration reduced the sensorial parameters in FC and the psychomotor parameters of both sexes. ln the acute experiments it was observed that GFR administration: 1) a decreased in MC and FC exploratory behavior. 2) in the LCE no anxiety-like symptoms; 3) in the TNF a reduced depressive-like effects in FC but not in MC. The long-term treatment produced: 1) in the CA and TNF a similar profile between MC and FC; in the LCE a reduced CM exploratory behavior. lt was concluded that GFR administration to adult mice produced a sexual dimorphic effects in the behavioral tests analyzed. The long term administration during puberty showed that GFR altered the sexual dimorphism in MC suggesting a endocrine disruptor effects when mice were exposed during puberty to this herbicide.