The Effect of Chronic Arsenic Exposure in Zebrafish

Abstract

Arsenic is a prevalent environmental toxin and a Group one human carcinogenic agent. Chronic arsenic exposure has been associated with many human diseases. The aim of this study is to evaluate zebrafish as an animal model to assess arsenic toxicity in elevated long-term arsenic exposure. With prolonged exposure (6 months) to various concentrations of arsenic from 50 ppb to 300 ppb, effects of arsenic accumulation in zebrafish tissues, and phenotypes were investigated. Results showed that there are no significant changes of arsenic retention in zebrafish tissues, and zebrafish did not exhibit any visible tumor formation under arsenic exposure conditions. However, the zebrafish demonstrate a dysfunction in their neurological system, which is reflected by a reduction of locomotive activity. Moreover, elevated levels of the superoxide dismutase (SOD2) protein were detected in the eye and liver, suggesting increased oxidative stress. In addition, the progenies of arsenic-treated parents displayed a smaller biomass (four-fold reduction in body weight) compared with those from their parental controls. This result indicates that arsenic may induce genetic or epigenetic changes that are then passed on to the next generation. Overall, this study demonstrates that zebrafish is a convenient vertebrate model with advantages in the evaluation of arsenic-associated neurological disorders as well as its influences on the offspring.

Dissipation of Micropollutants in a Rewetted Fen Peatland: A Field Study Using Treated Wastewater

“…Particularly collembolans and enchytraeids have been shown to be highly sensitive to arsenic with no observed effect concentrations (NOECs) at or below 10 mg/kg soil [93][94][95], while the plant Avena sativa and the bacterium Arthrobacter globiformis are far less susceptible [92]. The effects were most apparent in the second generation of exposed collembolans in the present study, which is in line with a recent report on transgenerational effects of arsenic in an aquatic organism, the zebrafish [96]. Hence, the impacted soil habitat quality for the collembolan and enchytraeid species at the study site clearly points at ecotoxicologically relevant concentrations of arsenic in the soil.…”

Zebrafish in Toxicology and Environmental Health

“…While information about the rate of arsenic metabolism by zebrafish in vivo and the production of specific metabolites are still emerging, it is clear that rodent models do not always accurately reflect the effects of human arsenic exposure. For instance, studies in rodents showed increased excretion and slower but more extensive methylation of arsenic when compared to humans so that ingested arsenic remains in the rodent blood stream for prolonged periods (Hallauer et al, 2016; States et al, 2011). …”

“…Chronic exposure of zebrafish to environmentally relevant concentrations revealed retention of arsenic in the eye, skin, and liver of 6-month-old fish and resulted in increased heart rate during larval stages and neurologic defects (Hallauer et al, 2016). Progeny of arsenic-exposed fish had reduced biomass at 3 months of age relative to the progeny of their unexposed siblings (Hallauer et al, 2016).…”

“…Progeny of arsenic-exposed fish had reduced biomass at 3 months of age relative to the progeny of their unexposed siblings (Hallauer et al, 2016). Zebrafish studies have recapitulated the effects of arsenic on the cardiovascular system (Hallauer et al, 2016; Li et al, 2012) and have shown alterations in liver metabolism and liver function (Lam et al, 2006; Li et al, 2016; Xu et al, 2013). Our research is focused on using zebrafish to understand the mechanisms that underlie arsenic-induced liver disease in human populations (Mazumder, 2005; Santra, Das Gupta, De, Roy, & Guha Mazumder, 1999).…”

Mixtures, Metabolites, and Mechanisms: Understanding Toxicology Using Zebrafish

“…7 Hallauer et al report how chronic arsenic exposure leads to neurological dysfunction and reduced body weight in progeny from exposed adults. 8 Finally, Baker et al examine the molecular and cellular changes in the testes after exposure to the persistent organic pollutant 2,3,7,8-tetrachlorodibenzodioxin, an endocrine disruptor that exerts transgenerational effects through the male germline.…”