Do Amazon turtles exposed to environmental concentrations of the antineoplastic drug cyclophosphamide present mutagenic damages? If so, would such damages be reversible?

Abstract

Antineoplastic drugs (AD) have been increasingly used, but the disposal of their wastes in the environment via hospital effluent and domestic sewage has emerged as an environmental issue. The current risks posed to these animals and effects of pollutants on the reptiles' population level remain unknown due to lack of studies on the topic. The aim of the present study was to evaluate the mutagenicity of neonate Podocnemis expansa exposed to environmental concentrations (EC) of cyclophosphamide (Cyc). The adopted doses were EC-I 0.2 μg/L and EC-II 0.5 μg/L Cyc. These doses correspond to 1/10 and ¼ of concentrations previously identified in hospital effluents. Turtles exposed to the CyC recorded larger total number of erythrocyte nuclear abnormalities than the ones in the control group after 48-h exposure. The total number of abnormalities for both groups (EC-I and EC-II) 96 h after the experiment had started was statistically similar to that of animals exposed to high Cyc concentration (positive control 5 × 10⁴ μg/L). This outcome confirms the mutagenic potential of Cyc, even at low concentrations. On the other hand, when the animals were taken to a pollutant-free environment, their mutagenic damages disappeared after 240 h. After such period, their total of abnormalities matched the basal levels recorded for the control group. Therefore, our study is the first evidence of AD mutagenicity in reptiles, even at EC and short-term exposure, as well as of turtles' recovery capability after the exposure to Cyc.

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