Effect of Nano- and Microzinc Supplementation on the Mineral Composition of Bones of Rats with Induced Mammary Gland Cancer

Background: The aim of this study was to determine changes in the mineral composition of the bones of rats with chemically induced mammary gland cancer and to attempt to establish whether a specific diet modification involving the inclusion of zinc ions in two forms—nano and micro—will affect the mineral composition of the bones. Methods: Female Sprague–Dawley rats were used for the research. The animals were randomly assigned to three experimental groups. All animals were fed a standard diet (Labofeed H), and selected groups additionally received zinc nanoparticles or microparticles in the amount of 4.6 mg/mL. To induce mammary cancer, the animals were given 7,12-dimethyl-1,2-benz[a]anthracene. The content of Ag, As, B, Ba, Cd, Cr, Cu, Mn, Ni, Pb, Rb, Se, Sr, Tl, U, and V was determined using ICP-MS, while that of Ca, Fe, K, Mg, Na, and Zn was determined using FAAS. Results: The use of a diet enriched with zinc nano- or microparticles significantly influenced the content of the elements tested. In the bones of rats fed a diet with zinc nanoparticles, changes were found in the content of Ca, Mg, Zn, Cd, U, V, and Tl, while in the case of the diet supplemented with zinc microparticles, there were differences in six elements—Ca, Mg, B, Cd, Ag, and Pb—compared to animals receiving an unsupplemented diet. Conclusions: The content of elements in the bone tissue of rats in the experimental model indicates disturbances of mineral metabolism in the tissue at an early stage of mammary cancer.