Zinc and low -dose of cadmium protect Sertoli cells against toxic - dose of cadmium: The role of metallothionein

The impact of cadmium (Cd) on male infertility may be related to the interaction with metal-binding proteins known as metallothioneins (Mts). Trace elements like zinc (Zn) have protective effects on testicular damage induced by Cd. We determined the effect of Zn and low-dose Cd pre-treatment on the expression of Mt1 and Mt2 genes on testicular Sertoli cells. The cultured TM4 mouse sertoli cells were treated with 50 μM ZnSO4 (Zn pre-treated group; ZnPG), 2 μM CdCl2 (Cd pre-treated group; CdPG), or distilled water (DW pre-treated group; DWPG). After 18 hour, all of these groups were exposed to 100 μM CdCl2 for different periods of time (1, 2, 3, and 6 hours). There was also a control group for all three groups, which was treated only with distilled water (without Cd or Zn pre-treatment). Cellular viability, Zn and Cd concentrations and gene expression were assessed by MTT, atomic absorption spectrometry and real time PCR methods, respectively. The expression of Mt1 and Mt2 genes in ZnPG, CdPG, and DWPG was greater than the control group (p=0.02 and p=0.01, respectively). Cd concentrations in CdPG and DWPG were greater than the control group (p=0.00). Expression of both genes in ZnPG and CdPG increased after 3 hours of treatment and Cd concentration decreased simultaneously, which was more obvious in ZnPG. Zn and short term low-dose Cd pre-treatment might reduce the adverse effects of Cd by increasing expression of Mts genes in Sertoli cells. The protective effect of Zn was stronger than Cd.