Efeito da exposição de microplásticos de polietileno sobre a integridade nuclear eritrocitária em lambari-do-rabo-amarelo, Astyanax lacustris (Lütken, 1875)

Abstract

The continuous expansion of synthetic polymer production, especially plastics, has resulted in greater availability of these materials in the environment. Improper management and disposal of plastic waste in water bodies contributes significantly to the increase in the concentration of microplastics (MPs) —small polymer particles—in different aquatic compartments, including lakes, rivers, and marine environments. This dynamic favors the direct exposure of aquatic organisms to such contaminants, increasing the associated ecotoxicological risks. This study aimed to evaluate the effects on the DNA of erythrocyte nuclei in Astyanax lacustris exposed to polyethylene microplastics (MP-PE). Specimens (n = 24) of A. lacustris were exposed to different concentrations of MP-PE (control, 15, 30, and 60 mg/L) for 10 days. At the end of this period, blood was collected for Comet assay analysis, and erythrocyte nuclei were evaluated qualitatively (degrees of alteration) and quantitatively (% of DNA in the comet tail), in addition to nuclear morphometry analysis accompanied by the micronucleus test associated with nuclear abnormalities. The increase in MP-PE concentration resulted in higher levels of damage to genetic material. All degrees of nuclear changes were observed from 30 mg/L exposure. Grade 3 was higher in specimens exposed to 60 mg/L. The percentage of DNA (trail) in the comet tail was also higher at all concentrations, especially at 15 mg/L. There were also significant changes in chromatin compaction and nuclear area, and nuclear alterations were observed. Our results demonstrate that the concentrations studied cause genotoxicity and cytotoxicity in exposed fish and may be harmful to the quality of the aquatic ecosystem.