Towards effective RIHT therapies: Identifying potential biomarkers for in vitro thyroid scaffold assessment

Radiation-induced hypothyroidism (RIHT) affects up to 92% of head and neck cancer patients post-irradiation, greatly impairing quality of life. Current treatments have limitations regarding efficacy and drug interactions. Tissue engineering offers promising alternative therapeutics, but there is currently a lack of specific protein markers expressed by thyroid cell lines that can be used to evaluate thyroid scaffolds in vitro. This study aimed to identify such proteins in the commonly used cell line Nthy-ori 3-1 based on expressional changes observed in a murine RIHT model.
Preliminary protein candidates were identified utilizing immunofluorescent (IF) analysis of murine thyroid glands at day 3 and 28 post-irradiation. A decrease in thyroxine confirmed induction of RIHT and a decreased in E-Cadherin expression, alongside an increase in α-smooth-muscle actin and fibronectin, suggested fibrosis. A transient reduction in Collagen-1 indicated excess extracellular matrix deposition and a decline in Zonula Occludens-1 thyroid epithelium disruption.
Furthermore, an electrospun 10% (w/v) polycaprolactone scaffold was fabricated. Scaffold morphology, mechanical properties, hydrophilicity and crystallinity were assessed. Nthy-ori 3-1 cell-seeded scaffold DNA content increased 6-fold, and metabolic activity doubled, over 14 days of study, with collagen-like fibril formation evident in osmium images. Transient α-smooth-muscle actin, fibronectin, zonula-occludens-1 and Collagen-1 expression changes mirrored irradiation-induced tissue disruption but normalized by day 14. Both E-Cadherin and thyroid peroxidase displayed increasing trends, suggesting a potential for scaffold-supported thyroid hormone production.
Although further research is required, this study identified key protein markers for assessing thyroid scaffold efficacy in vitro and underscored their potential for targeted tissue repair in RIHT.