Influence of environmental exposure to cadmium on placental tissue structure and metallothionein expression

Objective: To investigate the Significance of Metallothionein Expression on the Placental of Population Environmental Exposed to Cadmium. Methods: Pregnant women were chosen from one city of Hubei province from November 2002 to April 2003. Whole blood of the pregnant women, umbilical cord blood of neonates and placenta were collected and cadmium levels were determined by inductively coupled plasma emission mass spectroscopy. Immunohistochemistry staining and S-P method were used to observe the expression of the MT in placental tissue from 120 cases of human term placenta to analyze the potential association between MT and placental cadmium or umbilical cord blood cadmium in the pregnant women of environmental exposure to cadmium. Results: Maternal blood cadmium in 120 healthy pregnant women fluctuated from 0.27 to 13.00 μg/L and placental fluctuated from 0.033 to 1.69 μg/g dry weight. Cord blood cadmium fluctuated from 0.13 to 2.69 μg/L, all of which were lower than those significantly in maternal blood. Statistics analysis showed that the placental histopathologic change in the different MT expression group differs significantly. Log linear models analysis showed that the placental tissue change was probably associated with MT and maternal blood cadmium interaction. Conclusion: Results show that, cadmium exposure influences the structural changes in the placenta, and induces the of MT expression in placental tissue. Placental adaptability reaction was strengthened by MT, thus mitigating the trauma of the placental tissue. (authors)