Consequências metabólicas da água que bebemos: um estudo baseado em evidências de campo e experimentação com modelo animal

Abstract

Brazil is a major consumer of pesticides, and today it is already known that these compounds cause a several damages to health and ecosystems. Considering that the characteristics of the ecosystem which the human populations are part of influence the health of people who lives there, we studied a location in western Paraná, more specifically the municipality of Santa Tereza do Oeste, to identify the pesticides that are present in the soil and that could reach the groundwater in the region, or be consumed through water by the population. Soil from the region was collected and analyzed by Ferreira et al. (unpublished data) through physicochemical and chromatographic analysis, and DDT pesticide and its metabolites were found to be above the quantification limit. Based on these results, a simulation of a chronical exposure to water contaminated with the concentrations found in the soil was performed in animal model (16 Wistar rats divided into Control Group (n=8) and Exposure Group (n=8) focusing in target organs such as liver, kidney and brain, evaluating the antioxidant system and oxidative stress in these organs, and the liver function; with the exposure animals receiving water with contaminated with DDD and DDE (0,002 mg.L-1 of DDD and 0,005 mg.L-1 of DDE). During the animal experimentation, water consumption, food consumption, animal weight and animal naso-anal length were analyzed. Two blood counts were also performed: one at 70 days of experimentation and another at 100 days, the latter followed by animal euthanasia and collection of tissues. An aliquot of each tissue was homogenized and normalized to determine the activity of the enzymes: superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione S-transferases (GST); and also to measure the lipoperoxidation reaction (LPO). The liver tissue was also used to determine the activity of the enzymes: alanine amino transferase (ALT) and aspartate amino transferase (AST). In the statistical analyses, the Statistica 7 software was used for the biometric variables, and the Anova test for repeated measures was applied, followed by Tukey-HSD; and the R software was used for the enzyme analyses, and according to the assumptions of normality and homoscedasticity, the Student t-test or the non-parametric Mann-Whitney test was applied; and subsequently a Permutational Multivariate Analysis of Variance (PERMANOVA) was performed. The significance level used was 5% (p<0,05). It was evidenced that the exposure animals presented: higher weight and food consumption during the experiment; higher activation of GST in the liver, SOD in the kidney, and GPx in the brain; significant increase in ALT in the liver tissue; and a tendency to increase the hemoglobin concentration in the exposed animals. In an integrative analysis it was found that: the kidney and the brain were the most affected organs, showing significant activation of the antioxidant system and an increase in biometric variables among the exposed animals. In summary, this study showed that the environmental conditions to which the populations are exposed can directly influence the healthiness of individuals.