In vitro and in vivo studies of cytotoxic effects of FeSO4 nanoparticles

Background and aims: Using iron as a food additive usually causes undesirable sensory changes and side effects in humans. In this study, we made iron (Fe) nanoparticles (NPs) and studied the cytotoxicity of FeSO4 bulk and NPs on HT-29 cells and different doses of these particles on rat intestine. Methods: Particle size of nanoscale was achieved by mechanical technique. Iron particles were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of iron particles with different concentrations (6.25, 3.125, and 1.57 mM/mL) on the colon cell line was performed using the MTT assay at 24, 48, and 72 hours. Apoptosis and necrosis of the cells were assessed using Annexin V-FITC staining and propidium iodide (PI) at 24 h. In an in vivo study, Taftoon bread was produced from fortified wheat flour with FeSO4 bulk and NPs, which are recommended in human diet (9, 18, and 27 mg of elemental iron/kg flour). Wistar rats were fed daily with fortified bread for 21 days and their colon and small intestine were then evaluated histopathologically. Statistical analyses were performed using SPSS 22.0 software by chi-square test. Results: The synthesized FeSO4 NPs were smaller than 100 nm, and they had more adverse effects on the viability of the HT-29 cells compared to the bulk- FeSO4 at 72 hours. Flow cytometric study showed that the early apoptosis of cells by the bulk form was more than the NPs, but at the low concentration (1.57 mM/mL), the NPs induced more necrosis than the bulk particles (P=0.063). The survival rate of cells facing all concentrations of NPs and bulk- FeSO4 decreased dose dependently (P=0.075). In vivo results revealed that there were no pathological changes in rats’ intestinal tissues. Conclusion: The bulk and NPs of iron have adverse effects on the HT-29 cells, but no histopathological changes were seen on rats’ intestinal cells.