Background and Objective: Iron oxides nanoparticles have numerous applications in medical industry. Nanoparticles are particles with 100 nm in diameter. Despite their various applications, toxic effects of Iron oxide nanoparticles call for supplementary investigations. In this study, the toxic effect of iron oxide nanoparticles on lung development in fetal mice was examined.

Materials and Methods: Using in vivo technique, the mice were allocated to one of the following groups: the control group without the effect of nano iron oxide, sham group with injection of distilled water and experimental groups with low doses (10, 30 and 50 µg /kg) and high doses (10, 30 and 30 mg/kg) of nano iron oxide with 20 nm in diameters injected intraperitoneally on day 9 of pregnancy. On day 16 of pregnancy, embryos were removed and the lung tissue sections were assessed.

Results: The findings showed a significant decrease in the length of the fetus with 30 and 50 mg/kg doses and a significant decrease in the fetal weight and number of primitive bronchioles with 10, 30 and 50 mg/kg. Results  also showed a significant increase in lung weight and lung length with doses of 30 and 50 µg/kg, a significant increase in the number of alveolus with doses of 10, 30, 50 µg/kg and 10 mg/kg and a significant increase in the number of necrotic cells  with doses of  30 and 50 mg/kg.

Conclusion: Iron oxide nanoparticles showed dual effects. It is asserted throughout this study that fetal lung development increases at low doses and necrotic effect increases with high doses.