Intermittent oral administration of iron oxide nanoparticles modulates iron homeostasis, hematological, inflammatory, and organ-specific responses in iron-deficient rats.

Iron oxide nanoparticles (Fe₃O₄ NPs) are increasingly incorporated into biomedical and pharmaceutical applications and as alternative iron sources for treating anemia; however, their systemic effects under nonconventional dosing regimens remain incompletely understood. Therefore, this study aimed to conduct a comprehensive dose-response assessment of intermittent oral Fe₃O₄ nanoparticle dosing in iron-deficient rats. Iron deficiency anemia (IDA) was induced in male Wistar rats via an iron-deficient diet. The anemic rats received oral Fe₃O₄ nanoparticles (25-200 mg/kg) or ferrous sulfate (FS, 45 mg/kg) three times weekly for four weeks. Hematological recovery, iron status, IL-6 and hepcidin levels, organ function biomarkers, and histomorphometric parameters were assessed. IONPs restored iron homeostasis in a dose-dependent manner. Doses of 100 and 200 mg/kg normalized hemoglobin, hematocrit, and RBC counts to levels comparable to FS and the healthy controls, alongside significant improvements in serum iron, transferrin saturation, and ferritin. Although IONPs triggered a dose-dependent increase in IL-6 and hepcidin, the hepcidin response remained significantly lower than in the FS group. Histopathological analysis revealed a dose-dependent, hepatorenal toxicity profile. In conclusion, intermittent oral Fe₃O₄ NPs effectively correct anemia and restore iron parameters. However, these beneficial effects are counterbalanced by hepatorenal toxicity, suggesting the critical need for precise dose optimization in translational studies.