Effect of zinc on expression of zinc transporter 1 and metallothionein mRNA in primary cultured hippocampal neurons / 第二军医大学学报

ABSTRACT

Objective:To study the concentration response and time course of zinc transporter 1 (ZnT 1) and metallothionein (MT1/MT2) mRNA,as well as the cell viability to zinc exposure in primary cultured new born rats hippocampal neuron s. Methods: The cell viability were determined by trypan blue s taining at various concentrations of Zn 2+ (0, 50, 100, 125, 150, 175, 200 ?mol/L). The expression of ZnT 1, MT1 and MT2 mRNA to various concentrations of zinc exposure(0, 50, 75, 100, 125, 150 ?mol/L) and to 100 ?mol/L zinc exposure for different times (0, 2, 4, 6, 8 h) were determined b y real time fluorescent quantitative PCR. Results: The viabilit y of the neurons decreased significantly after 48 h once the concentration of Zn 2+ exceeded 125 ?mol/L,and the expression of ZnT 1 mRNA was in proportion to the increment of zinc.The expression of MT1/MT2 mRNA reached a plateau when the zinc concentration exceeding 75 ?mol/L. The expression of ZnT 1 mRNA peaked on about 2 h.However, the expression of MT1/MT2 mRNA reached its maximal around 6 h at the concentration of 100 ?mol/L. Conclusion: These results imply that although both MTs and ZnT 1 can attenuate the zinc toxicity, they may play different roles at different phases. ZnT 1 enhance the efflux of zinc prior to the sequesteration by MTs. Th e action of ZnT 1 may be durable, but the role of MTs may be satiable.