PFAS-mediated disruptions on thyroid histology

Abstract Introduction/Objective Per-and polyfluroalkyl substances (PFAS), are environmental contaminants of emerging concern due to their abundance in the environment and potential adverse health impacts. PFAS are used in waterproof clothing, makeup, carpets, upholstery, cookware, and fast-food containers. These organic pollutants have been found in the blood of 98% of Americans and have been linked to disruption in thyroid hormones. During fetal life, thyroid hormones are crucial for brain development and alterations in these hormones can induce long-term impacts on intellectual and brain impairments. T3 and T4 are known to be altered by PFAS exposure, but the mechanism by which this is done remains unclear. Methods/Case Report Normal thyroid cells were treated for 72 hours with 1000 nM solution containing either GEnX, PFOA, PFOS, or 1% DMSO control. Immunofluorescence for actin, tubulin, and DAPI was performed using a Nikon spinning disk. In vivo studies where 8-week-old mice are gavaged with 7.5 mg/kg of PFOS, PFOA, and GenX or PBS control for 8 weeks. Results (if a Case Study enter NA) We hypothesized the PFAS treatment alters thyroid cells morphology and histology. Immunofluorescence staining of normal thyroid cells treated with PFAS show a decrease in actin stress fibers compared to control cells. PFAS treated mice show a decrease in follicle size compared to control (average 1017 um2 size, p=0.0483). Conclusion This is the first study to show changes in thyroid histology after 8 weeks of PFAS exposure. As structure and function are closely linked, it is likely that this reduction in follicle size and actin reorganization contribute to alterations in thyroid function. Future studies are needed to illuminate the mechanism by which PFAS alter thyroid function in vivo. Understanding the role of PFAS-mediated thyroid dysregulation will have far reaching implications on environmental regulations and considerations for limiting PFAS in our environment.