Induction of renal metallothionein expression by nano-zinc in cadmium-treated rats

Induction of metallothioneins synthesis by cadmium and zinc is an adaptive/defensive mechanism against metal toxicity. In this study, the effect of size and dose of nano-zinc particles administered solely or simultaneously with cadmium to induce the synthesis of renal metallothioneins was investigated in male rats. Levels of renal metallothioneins (MTs) mRNA expression was estimated semiquantitatively after an oral exposure to different sizes (15, 20, and 30 nm) and doses (3, 10, and 100 mg/kg body weight (bw)) of nano-Zn and cadmium (2.5–5 mg/kg bw) using reverse transcription polymerase chain reaction. According to our results, renal MTs were induced significantly in response to the simultaneous use of cadmium and different doses of nano-Zn (20 and 30 nm) exposure (P < 0.005). The expression of MT mRNAs was significantly upregulated by nano-Zn 20 nm depending on the dose (P < 0.001). Our findings suggested that larger sizes and intensive doses of Zn nanoparticles can upregulate MT expression. In conclusion, coadministration of cadmium with nano-Zn particles could improve the induction of renal metallothionein synthesis. © 2013, Springer-Verlag London.