Assessing Toxicity of Fine and Nanoparticles: Comparing In Vitro Measurements to In Vivo Pulmonary Toxicity Profiles

Previous studies have reported little correlation between the relative toxicity of particle types when comparing lung toxicity rankings following in vivo instillation versus in vitro cell culture exposures. This study was designed to assess the capacity of in vitro screening studies to predict in vivo pulmonary toxicity of several fine or nanoscale particle types in rats. In the in vivo component of the study, rats were exposed by intratracheal instillation to 1 or 5 mg/kg of the following particle types: (1) carbonyl iron (CI), (2) crystalline silica (CS) (Min-U-Sil 5, alpha-quartz), (3) precipitated amorphous silica (AS), (4) nano-sized zinc oxide (NZO), or (5) fine-sized zinc oxide (FZO). Depending on…