Combined hepatic transcriptional effects of gamma radiation and depleted uranium on Atlantic salmon (Salmo salar)

To study the short-term hepatic transcriptional changes and identify potential modes of action, Atlantic salmon (Salmo salar) were exposed to 70 mGy external gamma radiation, 0.25 mg/L depleted uranium and combination of these two. A combination of high density (60 k) custom oligonucleotide salmonid microarray and quantitative real-time reverse transcription polymerase chain reaction (qPCR) was used to perform gene expression analyses. Differentially expressed genes (DEGs) were determined using one-way analysis of variance (ANOVA) and Tukey posthoc tests. Functional enrichment analysis based on Gene Ontology (GO) was performed to link DEGs to their biological functions. The Salmo salar DEGs were further mapped to mammlian orthologs. By using ortholog DEGs, gene networks were built based on well-curated mammlian protein-protein interactions and pathways analyses were performed to link DEGs to specific toxicological/biological functions. The results obtained from microarray analysis were further verified using qPCR. Juvenile Atlantic salmon were exposed to external gamma radiation emitted from a cobalt-60 source for 5h and waterborne depleted uranium for 48 h. Liver were samples and used for gene expression analysis.