Interactions between cadmium and zinc on gene expression pattern of differentiation markers in MC3T3-E1 cell line

We evaluated, in vitro, the interactions between cadmium (Cd) and zinc (Zn) during the proliferation and differentiation process using bone MC3T3-E1 cell line.Cells were treated with CdCl₂ and/or ZnCl₂ for 24 and 48 h and 5 µM CdCl₂ was found as low cytotoxic dose and 25 µM ZnCl₂ as the best Zn treatment for cell proliferation. Gene expression of some bone markers (Runx2, collagen α1 (Colα1), osteocalcin (Oc), alkaline phosphatase (ALP) and bone sialoprotein (BSP)) was studied at 24, 48 and 72 h.Treatment by CdCl₂ depressed Runx2, Colα1, and BSP mRNA levels after 24 h. Oc and ALP gene expression was found to be decreased after 72 h.CdCl₂ -exposure decreased ALP activity and Ca deposit in matrix. In concomitant treatment by CdCl₂ and ZnCl₂, gene expression of osteoblastic markers was found to be up-regulated (p < 0, 05) compared to CdCl₂ treated cells, ALP staining and mineralization were increased.Our results show that Zn could prevent Cd-induced toxicity on MC3T3-E1 cells, probably through the restoration of Runx2, col α1, BSP, ALP and Oc and gene expression inhibited by Cd.