Micronúcleos em pequenos mamíferos não voadores no biomonitoramento ambiental de fragmentos florestais do Cerrado

Abstract

Small mammals are effective models for environmental biomonitoring due to their sensitivity to contaminant exposure. Among biomonitoring techniques, the micronucleus test stands out for detecting small inclusions in erythrocytes, indicating genotoxic effects resulting from exposure to xenobiotics. The aim of this study was to test the hypothesis that animals captured in more urbanized areas would exhibit a higher number of micronuclei. A total of 138 individuals of Rhipidomys macrurus and 64 of Gracilinanus agilis were captured in four Cerrado remnants: two rural areas (Fazenda Água Fria and Reserva do Panga) and two peri-urban areas (Fazenda São José and Fazenda do Glória). Blood samples were collected and analyzed for micronucleus counts under optical microscopy. It was observed that 102 (73.9%) individuals of Rhipidomys macrurus presented micronuclei, 25 (69.4%) from rural areas, with a mean of 1.36±1.26 and 77 individuals (75.5%) from peri-urban areas with a mean of 3.69±3.35. For Gracilinanus agilis, 47 (77.0%) individuals presented micronuclei, nine (69.2%) from rural areas with a mean of 1.84±1.77 and 38 (79.1%) from peri-urban areas with a mean of 3.04±2.45. The number of micronucleus was higher in peri-urban than rural areas for R. macrurus, althouth we failed to any difference for G. agilis. In conclusion, the micronucleus test proved to be an effective tool for biomonitoring in Rhipidomys macrurus, confirming the association between urbanization level and increased genotoxicity. The lack of association in Gracilinanus agilis suggests a species-specific response to environmental contaminants, which may be related to ecological factors such as diet and behavior that influence exposure.