Plasticity of blood and liver biomarkers in Physalaemus nattereri exposed to agricultural systems

Abstract

Anurans are vulnerable to damage caused by the modification of habitats, as well as their contamination by xenobiotic substances. However, little is known of the plasticity of biomarkers once the exposure to these conditions has ceased. The present study evaluated whether Physalaemus nattereri is subject to erythrocytic nuclear alterations and modifications of the hepatic melanin in agricultural environments, and whether these impacts are reduced when the animal is isolated from this exposure. Twenty adult P. nattereri were collected from soybean (n = 10) and sugarcane (n = 10) plantations for the analysis of erythrocytic nuclear abnormalities and the hepatic melanin. An additional 20 animals were taken from the same environments and were maintained in contaminant-free terrariums under controlled conditions in the laboratory for 30 days prior to the application of the same analytical procedures. The results indicated that the animals from agricultural environments had higher levels of mutagenic damage in comparison with the individuals that were isolated from exposure to contaminants in the laboratory. The analysis of the hepatic melanin revealed a smaller area occupied by the melanomacrophages in the animals exposed to both types of plantation. The evidence indicates that the biomarkers are highly plastic, and reflect the environmental conditions, given that the genotoxic alterations decrease once the exposure is interrupted. The reduced area of hepatic melanin in the animals exposed to agricultural environments may reflect the incapacitation of the melanomacrophages and the loss of their detoxification potential due to the continuous exposure of the animal to agricultural pollutants.