Effects of Ingested Nanomaterials on Tissue Distribution of Co-ingested Zinc and Iron in Normal and Zinc-Deficient...

Cellulose nanofibers (CNF) reduced serum triglyceride levels in rats when co-administered with heavy cream by gavage. Do CNF and other nanomaterials (NMs) alter the tissue distribution and retention of co-administered metal ions? We evaluated whether 5 different NMs affected tissue distribution of co-ingested ⁶⁵Zn⁺⁺ and ⁵⁹Fe⁺⁺⁺ in zinc-replete versus zinc-deficient mice. Male C57BL/6J mice were fed either zinc-replete or zinc-deficient diets for 3 weeks, followed by gavage with NM suspensions in water containing both ⁶⁵ZnCl₂ and ⁵⁹FeCl₃. Urine and feces were measured for 48 h post-gavage. Mice were euthanized and samples of 22 tissues were collected and analyzed for ⁶⁵Zn and ⁵⁹Fe in a gamma counter. Our data show that zinc deficiency alters the tissue distribution of ⁶⁵Zn but not of ⁵⁹Fe, indicating that zinc and iron homeostasis are regulated by distinct mechanisms. Among the tested NMs, soluble starch-coated chitosan nanoparticles, cellulose nanocrystals, and TiO₂ reduced Zn and Fe tissue retention in zinc-deficient but not in zinc-replete animals.