Differential effect of nanoparticle and standard forms of ZnO on serum zinc and magnesium levels in rats.

This study examined the effect of chronic (2 weeks) administration of zinc oxide nanoparticles (NPs-ZnO) and standard zinc oxide (S-ZnO) on the levels of zinc (Zn), magnesium (Mg) and calcium (Ca) in rat serum. S-ZnO and NPs-ZnO were administered either per os (p.o.) or intraperitoneally (i.p.) at doses of 7 mg/kg or 14 mg/kg. Neither form of ZnO administered p.o. altered serum zinc concentration. However, different effects dependent upon either S-ZnO or NPs-ZnO forms were noticed after i.p. administration. Namely, while S-ZnO increased serum zinc concentration (by 136%) only at the higher dose (14 mg/kg), both doses of NPs-ZnO increased zinc concentration (by 97% at 7 mg/kg and by 564% at 14 mg/kg). The form-dependence of the ZnO effect was also demonstrated in the effect on the serum magnesium level. Only the S-ZnO form (at the dose of 14 mg/kg) reduced serum magnesium concentration (by 14% p.o., 6% i.p.). No influence of NPs-ZnO on the serum calcium level was observed. The present study demonstrated effects on the serum Zn and Mg levels, which differed between the standard and nanoparticle forms of ZnO. This may contribute to the different functional effects of these ZnO forms shown previously.