Background: The bioaccumulation and toxicity of Gold Nanoparticles (GNPs) in several organs of rats becomes of more necessity prior to using them in drug delivery, diagnostics, and treatment. The GNPs levels in several rat organs in vivo have not been previously documented. This study was aimed to evaluate the influence of size and exposure duration of GNPs on the GNPs levels in several organs of rats in vivo.
Methods: Thirty rats were divided into a control group (NG: n = 10), group 1 (G1A: infusion of 10 nm GNPs for 3 days; n = 5; G1B: 10 nm GNPs for 7 days; n = 5) and group 2 (G2A: 50 nm GNPs for 3 days; n = 5; G2B: 50 nm GNPs for 7 days; n = 5). 50 μl of GNPs dissolved in aqueous solution were administered intraperitoneally every day for 3 and 7 days.
Results: The GNPs levels were evaluated in several rat organs by Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) and Atomic Absorption Spectroscopy (AAS). In comparison with the control group, the GNPs levels increased in all the examined organs with G1A, G1B, G2A and G2B. The highest percentage normalized increase in the liver and lung organs were 468.6% and 273.4%, respectively with 10 nm GNPs after administration period of 7 days. The highest percentage normalized increase in the kidney and heart organs were 258.7% and 242.6%, respectively with 10 nm GNPs for administration period of 3 days.
Conclusions: Our results might indicate that GNPs are mostly taken up and accumulate in organs, suggesting the toxic effects induced by the smaller GNPs. These conclusions are further supported by histological investigation suggesting that the highest toxic effects were induced by the smaller GNPs and related to the time exposure of GNPs.