Responses of zebrafish (Danio rerio) cells to antibiotic erythromycin stress atthe subcellular levels

Erythromycin (ERY) is one of the most used antibiotics frequently detected in different aquatic environments and maybring burdens to aquatic ecosystems. However, the impacts of antibiotics on aquatic systems other than the antibioticresistance genes remain largely unknown. In the present study, the responses to ERY exposure at the subcellular-organelle levels were for thefirst time investigated and imaged over 24 h. Exposure to ERY hampered the zebrafish(Danio rerio) cell growth and decreased the cell viability in a time-dependent mode. Meanwhile, exposure to a lowconcentration of ERY (73.4 mu gL-1) induced reactive oxygen species (ROS) overproduction and lysosomal damagefollowing lysosomal alkalization and swelling. In turn, the lysosomal stress was the major driver of altering the ROSlevel, superoxide dismutase (SOD) activity, and glutathione (GSH) content. Subsequently, mitochondria displayeddysfunction such as increased mitochondrial ROS, impaired mitophagy, and induced mitochondria-driven apoptosis,as well as impaired mitochondrial electron transport chain and loss of membrane potential. These results collectivelydemonstrated the subcellular sensitive machinery responses to ERY stress at environmentally relevant and slightlyhigher sub-lethal concentrations. ERY may induce switching from autophagy to apoptosis with corresponding changesin lysosomal activity, antioxidant activity, and mitochondrial activity. Thefindings provided important information onthe physiological and subcellular responses offish cells to ERY.

Automated summary

This study investigated the impact of erythromycin on subcellular-organelle levels in zebrafish cells. The results showed that erythromycin exposure decreased cell viability, induced lysosomal damage and reactive oxygen species overproduction, and resulted in mitochondrial dysfunction and cell apoptosis.