Gene expression of zebrafish embryos exposed to titanium dioxide nanoparticles and hydroxylated fullerenes

Increased release of engineered nanoparticles to the environment suggests a rising need for the monitoring and evaluation of potential toxicity. Zebrafish frequently have been used as a model species in human and aquatic toxicology studies. In this study, zebrafish embryos were microinjected in the otic vesicle with a sublethal dose of engineered nanoparticles (titanium dioxide/TiO2 and hydroxylated fullerenes/C60(OH)24). A gene microarray analysis was performed on injected and control embryos to determine the potential for nanoparticles to change the expression of genes involved in cross talk of the nervous and immune systems. The exposure to TiO2 and hydroxylated fullerenes caused shifts in gene regulation response patterns that were similar for downregulated genes but different for upregulated genes. Significant effects on gene regulation were observed on genes involved in circadian rhythm, kinase activity, vesicular transport and immune response. This is the first report of circadian rhythm gene deregulation by nanoparticles in aquatic animals, indicating the potential for broad physiological and behavioral effects controlled by the circadian system.