Sub-lethal UV radiation during early life stages alters the behaviour, heart rate and oxidative stress parameters in zebrafish (Danio rerio)

Abstract

Environmental UV radiation in sufficient doses, as a possible consequence of climate change, is potent enough to affect living organisms with different outcomes, depending on the exposure life stage. The aim of this project was to evaluate the potentially toxic effects of exposure to sub-lethal and environmentally relevant doses of UVA (9.4, 18. 7, 37.7 J/cm 2) and UVB radiation (0.013, 0.025, 0.076 J/cm 2) on the development and behaviour in early life stages (4.5-5.5 hours post fertilization, hpf) of the zebrafish (Danio rerio). The used doses were all below the median lethal dose (LD50) and caused no significant difference in survival, deformities, or hatching between exposed and control groups. Compared to controls, there were transient UVA and UVB exposure effects on heart rate, with dose dependent reductions at 50 hpf, and at 60 hpf for UVA only. The UVB exposure caused an increasing trend in reactive oxygen species (ROS) formation at the two highest doses, even though only significant at 120 hpf for the second highest dose. Both UVA and UVB caused an increasing trend in lipid peroxidation (LPO) at the highest doses tested at 72 hpf. Furthermore, UVA exposure led to significant reductions in larval movement following exposure to the two highest doses of UVA, i.e., reduction in the time spent active and the total distance moved compared to control at 100 hpf, while no effect on the swimming speed was observed. The lowest dose of UVA had no effect on behaviour. In contrast, the highest dose of UVB led to a possible increase in the time spent active and a slower average swimming speed although these effects were not significant (p = 0.07). The obtained results show that UV doses below LD50 levels are able to cause changes in the behaviour and physiological parameters of zebrafish larvae, as well as oxidative stress in the form of ROS formation and LPO. Further testing is necessary to assess how this type of radiation and the effects observed could affect fish population dynamics.

Consequences of directly- and indirectly-experienced heat stress in a mutagenic environment

“…Many cell components were altered by UVR, leading to the activation of autophagy pathways to remove damaged macromolecules (Sample and He, 2017). These cellular effects escalated to the organismal level, resulting in hypoactivity, teratogenicity, and reduced hatching, as previously reported in zebrafish embryos (Charron et al, 2000;Hurem et al, 2018).…”

“…We explored the effects of stress history on the UVA-catalysed recovery from UVB-induced damage in zebrafish embryos. UVR is known to cause oxidative stress toxic to lipids, antioxidants, ribosomes, proteins, and nucleic acids (Dahms and Lee, 2010; Hurem et al, 2018; Iordanov et al, 1998). Here, UVR altered the metabolism of macromolecules (ribosomes, mRNA, protein), DNA checkpoints, and organ development.…”

“…Other repair mechanisms include nucleotide excision repair to substitute damaged nucleotides (Dahms and Lee, 2010; Griffiths et al, 1998; Rastogi et al, 2010), mismatch repair to remove mispaired bases (Jiricny, 2013) and homologous recombination and non-homologous end joining to repair double-strand breaks (Minten and Yu, 2019; Rastogi et al, 2010). Failure to mount such repair responses to UVR can impair immunity (Cramp et al, 2014; Salo et al, 2000), and scale up to whole-body damage such as altered behaviour, locomotion, increased malformation, and in turn, mortality (Alves and Agustí, 2020; Downie et al, 2023; Hurem et al, 2018). UVB may also induce inheritable epigenetic changes such as histone modifications, resulting in inherited resistant phenotypes (Reardon et al, 2022; Shen et al, 2017).…”

Captivating Colors, Crucial Roles: Astaxanthin’s Antioxidant Impact on Fish Oxidative Stress and Reproductive Performance

“…Inflammatory responses activate immune cells, such as neutrophils and macrophages, which produce ROS through enzymes like NADPH oxidase during their antimicrobial defense mechanisms, contributing to ROS production during inflammation [39]. External elements, including exposure to pollutants, heavy metals, and ultraviolet radiation, can intensify ROS generation [40,41]. The cumulative effect can overwhelm the antioxidant defense system, encompassing both enzymatic antioxidants like superoxide dismutase, catalase, and glutathione peroxidase, as well as non-enzymatic antioxidants such as vitamins C and E, glutathione, and carotenoids [42,43].…”

Xenopus: An in vivo model for studying skin response to ultraviolet B irradiation

“…To investigate the cellular responses to UVB, several models have been used including monolayer cells, skin equivalent, skin explant, and mouse models (Cario‐Andre et al, 2000; Cario‐Andre et al, 2002; Duval et al, 2001; Mahfouf et al, 2019; Raad et al, 2017; Rezvani et al, 2006; Rezvani et al, 2007; Scott, 2002). Besides mouse as the favorite mammalian model, several aquatic species, ranging from crustacean and echinoderm to different species of fish and amphibian, have been used to investigate the effects of UV radiation on development and behavior (Blaustein et al, 1997; Bonaventura et al, 2021; de Quadros et al, 2016; Dong et al, 2007; Hurem et al, 2018; Mahmoud et al, 2009; Nahon et al, 2009; Sayed et al, 2013; Sayed et al, 2016; Smith et al, 2000). Of note, increasing UVB radiation due to ozone layer depletion and consequently persistent UVB‐induced damage have been proposed as a potential cause for the disappearance of amphibian populations (Blaustein & Belden, 2003).…”