Ecotoxicological evaluation of water from the Sorocaba river using an integrated analysis of biochemical and morphological biomarkers in bullfrog tadpoles, Lithobates catesbeianus (Shaw, 1802).

Abstract

The aquatic environment is continuously subject to toxic contaminants as a result of industrial and domestic activities. The evaluation of the effects these contaminants on aquatic organisms at different levels, that are, cellular, tissue, biochemical and molecular, will contribute to the predictability of the effects caused by different pollutants in the environment, generating information about mechanisms of adaptation to environmental stressors. Thus, this work has the objective of investigating the organs (liver, kidney, muscle, brain and skin) of bullfrog tadpoles, Lithobates catesbeianus, if the exposure to water of the Sorocaba River can impose limits in the performance of the enzymatic and metabolic activities impairing thus skills such as growth and reproduction. The experimental project will consist of submitting groups of animals in the water of the Sorocaba River in the dry and rainy periods at five days. The presence of metals, agrochemicals and drugs will be determined in samples of waters of the Sorocaba River in the two periods and in two points. For an evaluation of the effects, the parameters will be analyzed: genotoxic analyzes and nuclear abnormalities in the peripheral blood of the animals; activity of antioxidant enzymes: SOD (superoxide dismutase), CAT (catalase), GPx (glutathione peroxidase), GR (glutathione reductase) and GST (glutathione S-transferase); levels of PCO (carbonyl proteins) and MT (metallothionein); activity of NOS (nitric oxide synthase) and AChE (acetylcholinesterase) (brain and muscle); concentration of MXR (multixenobiotic resistance system) proteins (liver and kidney) and determination of the activity of enzymes involved in the glucose metabolism: HK (hexokinase), PFK (phosphofructokinase), PK (pyruvate kinase) and LDH (lactate dehydrogenase). The levels of glucose, glycogen, lipid and protein are also determined in the different organs. Morphological biomarkers and hepatic catabolic substances (hemosiderine and lipofuscine) will also be investigated and may be correlated with lipid metabolism and erythrocyte degradation. (AU)