Cadmium Perturbs Expression of Brain aromatase (CYP19b) mRNA and Motility in Early Development of Zebrafish (Danio rerio)

Cadmium is known as a metalloestrogen, which acts on estrogen receptors to mimic effects of estrogen. Since that, we establish behavior marker and biomarker of cadmium for environmental monitoring by observing effect of cadmium on estrogen signaling pathways. To investigate effects of cadmium on development of motor behaviors in zebrafish larvae, we measured responding of fish to tactile stimulation (Motility). Immunocytochemistry (ICC) and RT-PCR were performed to reveal effect of cadmium on tyrosine hydroxylase (TH) and brain aromatase mRNA, respectively. Embryos were exposed to 0.01-10 μM CdCl 2 and 10 μM ICI 182.780 (ICI, estrogen receptor blocker) after 2 hour postfertilization (hpf). CdCl 2 exposure decreased response to tactile stimulation in a dose-dependent manner at 48 and 72 hpf. Co-incubation of ICI did not prevent decreased of response. Immunocytochemistry showed that cadmium did not change TH expression, while RT-PCR result exhibited that cadmium increased expression of brain aromatase mRNA. se results demonstrated that cadmium perturbs expression of brain aromatase mRNA and motility as one of behavior parameters in zebrafish larvae. How cadmium interacts with estrogen signaling to affect behaviors remains to be elucidated. From se result, we conclude that motility can be used as behavior marker of cadmium for environmental monitoring. In addition, Brain aromatase expression in zebrafish embryos could be utilized as biomarker of cadmium or endocrine disrupter to monitor aquatic environment