Consequências da exposição ao levonorgestrel em zebrafish: efeitos persistentes e transgeracionais

Abstract

The consumption of contraceptive medications such as levonorgestrel (LNG) has increased considerably in recent decades, and consequently its disposal in the environment, and it has already been detected in different concentrations in the aquatic environment. These substances are biologically active and can affect the reproduction, physiology and behavior of non-target organisms, such as fish, harming the perpetuation of the species and the ecological balance in general. In the first phase of the study, exposure to LNG early in development in the parental generation causes negative effects related to anxiety in zebrafish larvae, which persist into adulthood, in addition to affecting hormonal parameters, such as increased cortisol. Furthermore, it causes harm to the survival rate in all those tested, and to the rate ratio of males and females. The second phase encompasses a transgenerational analysis. For this, after the adult phase was reached, the parental generation was reproduced to obtain unexposed offspring, and the entire experimental protocol carried out in the embryonic and larval phase of the parental generation was reproduced, in addition to analyzing cortisol levels. Anxiety behavior disorder occurs in the profile, as does a low survival rate at higher concentration. The imbalance found in taxa of males and females subjected to an inability to reproduce successfully, and the failure to obtain eggs at the lowest concentration tested. With these studies, we demonstrate the physiological and behavioral effects caused by exposure to LNG in the early stages of development that persist into adulthood, and appear in the offspring, increasing knowledge about environmental contaminants.