A priming dose protects against gold nanoparticles-induced proinflammatory cytokines mRNA expression in mice

To study the effect of priming doses of gold nanoparticles (GNPs) on proinflammatory cytokines in different organs of mice. Mice were injected with a single or two doses (priming group) of GNPs (5, 20 and 50 nm) and sacrificed after 1 or 7 days. The mRNA expressions of IL-1β, IL-6 and TNF-α were determined in liver, kidney and spleen. A single injection of 5 nm GNPs significantly increased the mRNA expressions of IL-1β and IL-6 in liver, which were normalized on day 7. In spleen, the GNPs of all sizes significantly increased IL-1β and IL-6 mRNA expressions on day 1 that persisted on day 7. The priming dose of GNPs protected the animals against the acute phase induction of IL-1β and IL-6 expressions in liver and spleen. Primed animals showed protection against GNP-induced acute immune activation suggesting the importance of the priming dose in nanomedicine. Gold nanoparticles (GNPs) have currently become one of the most ideal nanomaterials for biomedical applications including drug delivery and imaging. However, recent reports about an acute phase increase in proinflammatory cytokines by GNPs reflect a negative impact on their medical applications. In this investigation, we report that a priming dose of GNPs significantly inhibit the induction of acute phase immune response in GNP-treated mice suggesting the importance of the priming dose in nanomedicine.