Effects of Lithium and 2,4-Dichlorophenol on Zebrafish: Circadian Rhythm Disorder and Molecular Effects

Abstract The aim of this study was to investigate lithium and 2,4-dichlorophenol (2,4-DCP)-induced circadian rhythm disorder and their genome-wide effects in zebrafish. Zebrafish larvae were exposed to 250 ppm LiCl (n = 40) or 20 ppm 2,4-DCP. RNA was subsequently extracted and determined quantitatively. The mRNA levels of circadian clock-related genes, including clock1a, bmal1b, per2, and per1b, were determined. Microarray datasets were generated and the differentially expressed genes (DEGs) were identified. The mRNA levels of some upregulated and downregulated DEGs were examined by quantitative real-time polymerase chain reaction (RT-PCR). Finally, gene ontology (GO) enrichment analysis was applied to determine the roles of the DEGs. The mRNA expression levels of circadian rhythm-related genes in the daily cycle were significantly affected after incubation of zebrafish with LiCl and 2,4-DCP. Many genes were differentially expressed during the light phase (97 h) and RT-PCR validation tests revealed that t...