Hypoxia regulates cytokines expression and neutrophils migration by ERK signaling in zebrafish

Normal dissolved oxygen in water is essential for maintaining the physiological functions of fish, but environ-mental pollution, such as eutrophication can lead to a decrease in oxygen content in water. How this reduction of dissolved oxygen in water affects the immune functions of fish and the potential regulatory mechanisms have not been thoroughly elucidated. In this study, we made full use of the aquatic model animal zebrafish to explore this question. In a model of LPS-induced inflammation, we found that hypoxia induced by infusing nitrogen into water increased the expression of pro-inflammatory cytokines, such as il-1 beta, il-6, and il-8. In vivo imaging also showed that hypoxia significantly increased neutrophil migration to the site of caudal fin injury in the transgenic line. Subsequently, we found that the phosphorylation level of ERK protein was significantly activated upon hypoxia and proved the roles of ERK signaling in the expression of pro-inflammatory cytokines and neutrophil migration in zebrafish. This study indicated that reduced water oxygen significantly increases the inflammatory response of the zebrafish.

Automated summary

This study utilized zebrafish as an aquatic model animal to investigate the effects of reduced dissolved oxygen in water on the immune functions of fish and potential regulatory mechanisms. The results showed that hypoxia significantly increased the expression of pro-inflammatory cytokines and promoted neutrophil migration. Furthermore, the activation of the ERK signaling pathway was found to play a role in this process.