Cadmium (Cd) is an increasingly important environmental pollutant due to its high toxicity to fish and aquatic animals. In the present study, we cultured common carp (Cyprinus carpio L.) in two groups, a control group and a Cd group, with the Cd group being exposed to Cd for 30 d. The antioxidant enzyme activities of T-AOC and CAT and the GSH content were differentially decreased during Cd exposure. miRNAome profiling indicated that 23 differentially expressed miRNAs were potential biomarkers for Cd exposure; 7 miRNAs were up-regulated, and 16 miRNAs were down-regulated. The expression levels of miR-122, novel-miR6, miR-193a-3p and miR-27a-5p in the Cd group were 0.43-fold, 0.47-fold, 0.49-fold and 2.4-fold greater than in the control group, respectively. qRT-PCR further detected that the expression levels of apoptosis-related genes, including BAX, BAD, BAK, CASPASE9 and PIDD, were differentially increased, while BCL2 was decreased. Western blot analysis showed that the protein expression levels of BAX and BAD were increased and that of BCL2 was differentially decreased during Cd exposure. Alterations in the levels of miR-122, novel-miR6, miR-193a-3p and miR-27a-5p expression may play an important role in diagnosing oxidative stress-induced apoptosis during Cd exposure in the head kidney. These markers may contribute to diagnosing the early stage of Cd exposure in common carp.
Keywords: Biomarker; Cadmium; Carp; Head kidney; microRNA profile.
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