Effects of surface charge and palladium on hepatic and kidney injury induced by polystyrene nanoparticles co-administered to mice with paraquat and cisplatin.

Recently, with the advancement of nanotechnology, various nanoparticles have been developed and used in fields such as electronics, cosmetics, and foods. However, the toxicity of nanoparticles has yet to be fully investigated. In particular, the interactions between nanoparticles and therapeutic drugs require further study. We previously reported that unmodified polystyrene nanoparticles with a particle size of 50 nm (NPP50) co-administered with paraquat (PQ) or cisplatin (CDDP) induce hepatic and kidney injury. Here, we determined if NPP50 modified with the amino group (NPP50-NH2), carboxyl group (NPP50-COOH), or palladium (Pd-NPP50) caused liver or kidney injury when co-administered with PQ or CDDP. The results showed that when NPP50-NH2, NPP50-COOH, or Pd-NPP50 was administered alone via the mouse tail vein, serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and blood urea nitrogen (BUN) did not increase or cause injury. When NPP50, NPP50-NH2, NPP50-COOH, or Pd-NPP50 was co-administered with PQ, serum levels of ALT and AST increased in the NPP50 group but did not increase in the NPP50-NH2, NPP50-COOH, or Pd-NPP50 groups. When NPP50-NH2, NPP50-COOH, or Pd-NPP50 was co-administered with CDDP, ALT, AST, and BUN values did not increase. These data suggest that injury due to the interaction of polystyrene nanoparticles with CDDP or PQ can be suppressed by changes in the surface charge of nanoparticles or by Pd modification.