Combined toxicity of silica nanoparticles and cadmium chloride on the cardiovascular system of zebrafish (Danio rerio) larvae

Silica nanoparticles (SiNPs) and cadmium are major environmental pollutants that have severe detrimental effects on living organisms. Recent studies have demonstrated that the combined exposure of SiNPs and heavy metals is more toxic than individual exposure. However, studies on the effects of the combined exposure of SiNPs and cadmium, on the cardiovascular system are rare. In this study, zebrafish (Danio rerio) embryos were exposed to a combination of SiNPs and experimentally safe concentrations CdCl2 for studying the alterations in heart morphology, heart rate, apoptosis, and vascular endothelial cells. The results demonstrated that the detrimental effects of SiNPs+CdCl2 exposure on the heart rate and vascular endothelial cells were more severe than those following exposure to SiNPs or CdCl2 alone. Gene expression analysis revealed that apoptosis and inflammation could be the major pathways underlying the toxicity caused by the combined exposure of SiNPs and CdCl2.