Comparison of biodistribution of cerium oxide nanoparticles after repeated oral administration by gavage or snack in Sprague Dawley rats

The rate of translocation of ingested nanoparticles (NPs) and how the uptake is affected by a food matrix are key aspects of health risk assessment. In this study, female Sprague Dawley rats (N=4/group) received 0, 1.4, or 13 mg of cerium oxide (CeO₂ NM-212) NPs/rat/day by gavage or in a chocolate spread snack 5 days/week for 1 or 2 weeks followed by 2 weeks of recovery.
A dose and time-dependent uptake in the liver and spleen of 0.1–0.3 and 0.004–0.005 parts per million (ng/mg) of the total administered dose was found, respectively. There was no statistically significant difference in cerium concentration in the liver or spleen after gavage compared to snack dosing. Microscopy revealed indications of necrotic changes in the liver and decreased cellularity in white pulp in the spleen. The snack provided precise administration and a more human-relevant exposure of NPs and could improve animal welfare as alternative to gavage.