Intraperitoneal exposure of iron oxide nanoparticles causes dose-dependent toxicity in Wistar rats

Nanoparticles of iron oxide, with diameters beteween 1 to 100 nm, have notable implications for human health and well being. In the current study, we have investigated the effects of iron oxide nanoparticles (IONP) exposure on general physiology and health of adult Wistar rats. IONP used in the study had spherical shape and average size in the range of 15-20 nm. A total of eight groups of rats were repeatedly injected with 0 (control), 20, 40, and 80 mg IONP per kg body weight intraperitoneally under two different exposure schemes (sub-acute and sub-chronic). IONP exposure caused significant changes in lungs, liver, and kidney indices in both exposure schemes. Sub-acute exposure did not affect body weight gain in treated rats, but longer duration exposure was responsible for significant reduction in body weight. Mesenteries, visceral fatty tissues, and visceral peritoneal membranes demonstrated apparent accumulations of IONP in a dose and time-dependent manner. Hematological analysis showed that total RBC count, hemoglobin content, hematocrit, mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC) and mean platelet volume (MPV) were not affected by IONP exposure. Total lymphocyte count, however, was elevated in low- and mid-dose treated rats, but not in high-dose group. Serum lactate dehydrogenase (LDH) increased significantly in rats treated with mid and high doses as compared to control. Serum creatinine and blood urea nitrogen levels were also significantly altered in treated rats. Histological study found significant hepatic damage and mild spleen toxicity. Our report suggests that IONP exhibit significant toxicity in rats.