Exposing Zebrafish to Silver Nanoparticles during Caudal Fin Regeneration Disrupts Caudal Fin Growth and p53 Signaling

Zebrafish were exposed to commercial silver nanoparticles (similar to 10-20 nm) at 0.4 and 4 ppm during cadual fin regeneration. The silver was in the Ag+ ionic form. Fin regeneration was slow in the group exposed to the lower concentration. The cadual fin, gill, and muscle were assayed after 48 hours and subjected to histological analysis. In all tissues sampled, fish exposed to nanoparticles exhibited infiltration, large mitochondria with empty matrices, and accumulation of nano-sized silver in blood vessels. The results suggested mitochondrial damage and induction of inflammation. Microarray analysis of RNA from young zebrafish (52 hours post-fertilization) that were exposed to manometer-sized silver particles, showed alteration in expression of the p53 gene pathway related to apoptosis. Gene expression changes in the nanoparticle-treated zebrafish led to phenotypic changes, reflecting increased apoptosis.