Thyroid hormone disrupting activity of house dust and related pollutants

Objective To detect the thyroid hormone disrupting activity of house dust extract with the reporter transcriptional activation assay. Methods The restructured reporter plasmid pUAS-tk-Luc, expression vector Gal4-L-TRβand transfection reagent SofastTM were transfected into HEK-293 cells. Different concentrations of house dust extract, and five nmol/L triiodothyronine (T3) were added into the culture medium. The expression of the luciferase was detected by the luciferase reporter gene detector. Simultaneously, 5 families of organic compounds with possibility to disrupting the thyroid hormone were analyzed. Results The one-way ANOVA linear trend test showed that the luciferase expression decreased with the increased concentrations of the extract, which indicated the decreased activity of the T3 with P<0.001. The luciferase expression of the 10.00 and 20.00 mg dust/mL groups was significantly lower than that of the 5 nmol/L T3 group (P=0.012 and 0.002, respectively). Chemical analysis showed that polycyclic aromatic hydrocarbons, phalate esters, polybrominated diphenyl ethers, polychlorinated biphenyl and phenols were 0.2-3.7 μg/g, not detected-117.4 μg/g, not detected-1.0 μg/g, 1.0-25.0 ng/g and not detected-32.5 μg/g, respectively. Conclusions The activity of the thyroid hormone could be inhibited by house dust extract by disrupting the combination with the thyroid hormone receptor, which indicated that the house dust exposure in early childhood might cause potential neuro developmental influence.