Avaliação da intoxicação mercurial sobre os parâmetros inflamatórios, estresse oxidativo e dosagem de aminoácidos e monoaminas no hipocampo de camundongos c57bl/6j jovens

Abstract

Methylmercury (MeHg) is highly toxic to the human brain. Although much is known about the neurotoxic effects of MeHg, the effects of MeHg on brain neurotransmitters are still little explored. In this study, we evaluated the effects of MeHg poisoning on hippocampus oxidative stress, neuroinflammation biomarkers and neurotransmitter levels in C57BL6J mice. Male rats at 6 weeks of age were used. The mice were housed in microinsulating cages and received water and food ad libitum. Intoxicated mice received MeHg in drinking water (20 mg/L) for twenty days. All protocols were approved by CEUA / UNIFOR (protocol no. 015 / 2015). Hippocampus samples were collected and frozen rapidly to evaluate the levels of myeloperoxidase (MPO), glutathione (GSH) and malondialdehyde (MDA) (μmol/mg protein) by ELISA. Hippocampal monoamines (dopamine and metabolites) and amino acid neurotransmitters (taurine, glutamate, gamma aminobutyric acid-GABA, tyrosine and glycine) were evaluated by HPLC. The unpaired Student's T-test was used to confirm significant data. P <0.05 was considered statistically significant. Mercurial intoxication was confirmed by an increase (p < 0.0001) of Hg concentration in the MeHg group. The intoxicated animals had a lower weight gain (p < 0.0001) compared to the control group. Higher concentrations of MPO (p < 0.0001) and MDA (0.0001) were observed in the animals of the MeHg group compared to the control group. Hippocampal dopamine (AD) concentrations were similar in the control and intoxicated groups, however, 3,4-dihydroxyphenylacetic acid (DOPAC), one of the metabolites of AD, were increased (0.41 ± 0.081 ng/g) (p < 0.0003) in the hippocampus of the intoxicated group in relation to the control group (0.08 ± 0.012 ng/g). Regarding the concentration of amino acids in (umol/mg of tissue), an increase in glutamate levels was observed in the MeHg group (251.9 ± 26.68) in relation to the Control (129.1 ± 22.48) (p < 0.003), taurine group MeHg (1141 ± 234) X Control group (542.5 ± 126.7) (p < 0.05) and GABA group MeHg (16775 ± 1592) X Control group (7642 ± 1964) (p < 0.002). Together, the findings of the present study show important biochemical changes in the hippocampus, high oxidative stress and MPO related inflammation.