BIOACCUMULATION AND TOXICOKINETICS OF THE ORALLY ADMINISTERED NANOSIZED NICKEL AND COBALT (II, III) OXIDES IN MALE ALBINO RATS

Nickel oxide (NiO) and cobalt (II, III) oxide (Co3O4) nanoparticles (NPs) are widely used together in alloys and as catalyzers. Yet, no information is available about the effect of their combination on mammals. The present work investigated the accumulation and the toxicokinetics of Ni and Co in the brain, liver, kidney and intestine of male albino rats during two weeks after an oral administration of 0.5 and 1.0 g per kg body weight of NiO-NPs and/or Co3O4-NPs. Characterization of the NPs via transmission electron microscope (TEM), X-ray diffraction (XRD) and dynamic light scattering (DLS) was performed. The average particle diameter, hydrodynamic size, polydispersion index and zeta potential were 16.90 nm, 91.54 nm, 0.394 and + 42.1 mV for the NiO-NPs and 20.68 nm, 92.03 nm, 0.235 and +41.5 mV for the Co3O4-NPs, respectively. In all tissues, Ni levels were markedly increased with increasing the administered doses of NiO-NPs. On the contrary, Co levels were remarkably reduced by elevating the doses of Co3O4-NPs. The highest levels of Ni and Co were reported in the intestine. The toxicokinetic parameters including the area under concentration curve (AUC), maximum concentration (Cmax), elimination rate constant (Lz), elimination half life time (t1/2), mean retention time (MRT) and last recorded concentrations (Clast) of Ni and Co were computed in all the studied organs. The rats administered with NiO-NPs and Co3O4-NPs together showed remarkable reductions in the AUC and Cmax of Ni and Co, as compared to those treated with either NiO-NPs or Co3O4-NPs separately. A marked increase in the Lz accompanied by remarkable reductions in the t1/2 and MRT of Ni in the kidney of rats administered with NiO-NPs and Co3O4-NPs together, as compared to those treated with NiO-NPs alone. Accordingly, the co-administration of NiO-NPs and Co3O4-NPs markedly reduced the absorption of the Ni and Co, whereas it increased their elimination rates. In conclusion, under the current experimental conditions, the NiO-NPs and Co3O4-NPs antagonized each other inside the body.