| The growing application of cerium oxide nanoparticles (CeO2 NP) in several industrial products is likely to be associated with increased risk of inhalation and exposure. How the inhalation of CeO2 NP may affect cardiac structure and function has to our knowledge, not been examined. To examine whether inhalation of CeO2 NP affects cardiac structure and function, male Sprague Dawley rats underwent a single intra tracheal instillation of nanoparticles (7 mg/kg body weight). Animals were sacrificed 1, 3, 14, and 28 days after instillation and protein isolates from the hearts were examined for the presence of oxidative stress, autophagy and apoptosis. Compared to 1 day saline controls, heart weights after instillation were decreased by 7.8 +/- 1.9%, 12.2 +/- 3.4%, 10.7 +/- 3.2%, and 18.6 +/- 3.9% at 1, 3, 14, and 28 days, respectively (p<0.05). Decreases in heart weight were associated with elevations in the expression of heat shock proteins (HSP) and NF-kB while the expression of AMPK-&agr; was decreased suggesting the induction of oxidative stress subsequent to CeO2 NP exposure. Further analysis demonstrated that the inhalation of the nanoparticles was also associated with elevations in the amount of Beclin-1 and LC3 which suggests that CeO2 NP exposure can induce autophagy in the rat heart. Taken together, these data suggest that the inhalation of CeO2 NP can cause increased cardiac oxidative stress and autophagy. |
