Adverse effects induced by chronic gamma irradiation in progeny of adult fish not affecting parental reproductive performance

Abstract

Multigenerational studies have become of great interest in ecotoxicology since the consequence of parental exposure to contaminants on offspring generations was established in situ or in laboratory conditions. The present study mainly examined the chronic effects of external Cs‐137 gamma irradiation exposure at 4 dose rates (control, 0.5, 5, and 50 mGy h–1) on adult zebrafish (F0) exposed for 10 d and their progeny (F1) exposed or unexposed for 4 to 5 d. The main endpoints investigated included parental reproductive performance, embryo‐larval survival, DNA alterations, and reactive oxygen species (ROS) production in F0 and F1. No effects on reproductive success, fecundity, or egg fertilization rate were observed. However, drastic effects were observed on F1 exposed to 50 mGy h–1, resulting in a mortality rate of 100%. The drastic effects were also observed when the progeny was not irradiated. It was demonstrated that the sensitivity of the embryos was mainly attributable to parental irradiation. Moreover, these drastic effects induced by adult irradiation disappeared over time when 10 d–irradiated adults were placed in a nonirradiated condition. Alterations in larval DNA were observed for the 3 dose rates, and an increase of ROS production was also shown for the 2 lowest dose rates. The present study improves our understanding of the consequences of parental exposure conditions to the progeny. Furthermore, it provides an incentive to take transmitted generational effects into account in ecological risk assessments. Environ Toxicol Chem 2019;38:2556–2567. © 2019 SETAC

Effects of gamma ionizing radiation exposure on Danio rerio embryo-larval stages - comparison with tritium exposure

“…Gamma irradiation has often been shown to induce DNA damages in zebrafish larvae at different dose rates, such as 3.3x10 1 µGy/h (Gagnaire et al 2015b) and from 4.16x10 2 to 4.16x10 5 µGy/h (Simon et al 2011). DNA damages also appeared in progeny when parents were exposed to gamma irradiation (Guirandy et al 2019) or when exposure occur during gametogenesis (Hurem et al 2018). However, at 2.4x10 4 µGy/h, DNA damages increased at 1 dpf and decreased at 4 dpf, suggesting that repair mechanisms occurred (Gagnaire et al 2015b).…”

“…The exact same kind of result was already shown for other pollutants, such as endocrine disruptors (Bado-Nilles et al 2014b) and uranium (Gagnaire et al 2015a, Gagnaire et al 2014, Le Guernic et al 2016. However, an increase of ROS basal level was shown in zebrafish progeny when parents were exposed to gamma irradiation (Guirandy et al 2019, Hurem et al 2017a). On the contrary, 4 dpf larvae exposed to 1.34x10 2 and 1.24x10 3 µGy/h showed also an increase of ROS production index, but this was due to an increase of the stimulated level, as shown before for agricultural products (Bado-Nilles et al 2014a).…”

Multigenerational exposure to gamma radiation affects offspring differently over generations in zebrafish

“…In most cases, the effects after gamma irradiation are assessed at specific sensitive stages, such as the embryo-larval stage, because they are considered to be most vulnerable to ionizing radiation (Gagnaire et al, 2015;Hu et al, 2016;Lerebours et al, 2020;Pereira et al, 2011;Praveen Kumar et al, 2017;Simon et al, 2011a). However, focusing on just one sensitive stage of life is not enough to obtain a comprehensive understanding of the effects ofirradiation in fish (Guirandy et al, 2019;Hurem et al, 2017a;. For example, at 50 to 53 mGy h -1 , F1 irradiated and non-irradiated progeny from F0 irradiated zebrafish (Danio rerio) showed 100% mortality, providing an evidence of transmitted effects from parents to progeny and thus the importance of assessing multigeneration studies These dose rates are not environmentally relevant but contribute to the development of the dose-responses relationships necessary for ERA.…”

“…. However, multigeneration studies on IR are scarce but they demonstrated that multigenerational exposure can lead to harmful effects and highlights new toxic mechanisms (see Guirandy et al 2019). These studies suggested that IR can induce (i) epigenetic alterations, such as DNA methylation located on gene promoters and enhancers, which can be inherited by future generations and (ii) altered transcriptomes.…”

“…In this study, we investigated whether multigenerational gamma irradiation ( 137 Cs) of zebrafish (Danio rerio) can affect the reproductive performances of animals and induce effects on F1 and F2 progenies (Guirandy et al, 2019;Hurem et al, 2017a;Hurem et al, 2018;Kamstra et al, 2018). We hypothesized that IR can influence reproductive performance across generations.…”