Abstract
AbstractVenlafaxine (VFX), a commonly prescribed antidepressant often detected in wastewater effluent, and acute temperature elevations from climate change and increased urbanization, are two environmental stressors currently placing freshwater ecosystems at risk. This study focused on understanding if exposure to VFX impacts the agitation temperature (Tag) and critical thermal maximum (CTmax) of zebrafish (Danio rerio). Additionally, we examined the interactive effects of VFX and acute thermal stress on zebrafish heat shock and inflammatory immune responses. A 96 hour 1.0 μg/L VFX exposure experiment was conducted, followed by assessment of thermal tolerance via CTmaxchallenge. Heat shock proteins and pro-inflammatory immune cytokines were quantified through gene expression analysis by quantitative PCR (qPCR) onhsp 70, hsp 90, hsp 47, il-8, tnfα, andil-1βwithin gill and liver tissue. No significant changes in agitation temperature between control and exposed fish were observed, nor were there any differences in CTmaxbased on treatment. Unsurprisingly,hsp 47, 70, and 90were all upregulated in groups exposed solely to CTmax, while onlyhsp 47within gill tissue showed signs of interactive effects, which was significantly decreased in fish exposed to both VFX and CTmax. No induction of an inflammatory response occurred. This study demonstrated that environmentally relevant concentrations of VFX have no impact on thermal tolerance performance in zebrafish. However, VFX is capable of causing diminished function of protective heat shock mechanisms, which could be detrimental to freshwater fish populations and aquatic ecosystems as temperature spikes become more frequent from climate change and urbanization near watersheds.Summary StatementThis study predicts the effects that climate change and anthropogenic pollutants may have on fish ability to tolerate elevated temperatures, and examines the physiologic challenges these stressors may introduce.
Publisher
Cold Spring Harbor Laboratory