Analyses of levels of thyroid hormones and its receptor expression in puerperants and newborns from an e-waste dismantling site

Abstract

In this study, the serum levels, including thyroid hormones free triiodothyronine (FT3), free thyroxine (FT4), thyroid stimulating hormone(TSH)among the subjects from the exposed group (n = 48) and the control group (n = 45) were detected by immuno radiometric assay (IRMA). The expression levels of TRα1, TRβ1, TSHR mRNA in placentas and umbilical cords were detected by fluorescent quantitative real-time PCR (FQ-PCR). The correlations between the thyroid hormone levels in maternal serum and umbilical serum, and between the expression levels of its receptors mRNA in placentas and umbilical cords were determined. We found that the FT4 levels of both maternal serum and umbilical cord serum in the exposed group were lower than those in the control (P < 0.05). However, the increased TSH levels in the exposed group had statistically significance compared to those in the control group (P < 0.05). The TRα1 and TRβ1 mRNA levels both in placentas and umbilical cords in the exposed group were lower than those in the control group (P < 0.05 and 0.01). However, the TSHR mRNA levels in the exposed group were significantly different compared to those in the control group (P < 0.01). The serum FT4 and TSH levels of parturient women were positively correlated with those of the newborns in both groups (P < 0.05 and 0.01). The mRNA levels of TRα1, TRβ1 and TSHR in the placentas were positively correlated with those in umbilical cords in both groups (P < 0.01). The findings suggest that some environmental pollutants existing in the electronic waste (e-waste) dismantling region may affect the health of local parturient women and newborns, representing changes both in serum levels of thyroid hormones and in mRNA expression of its receptors.