Optimizing decellularization protocols for human thyroid tissues: a step towards tissue engineering and transplantation.

Hypothyroidism is caused by insufficient stimulation or disruption of the thyroid. However, the drawbacks of thyroid transplantation have led to the search for new treatments. Decellularization allows tissue transplants to maintain their biomimetic structures while preserving cell adhesion, proliferation, and differentiation. This study aimed to decellularize human thyroid tissues using a structure-preserving optimization strategy and present preliminary data on recellularization. Nine methods were used for physical and chemical decellularization. Quantitative and immunohistochemical analyses were performed to investigate the DNA and extracellular matrix components of the tissues. Biomechanical properties were determined by compression test, and cell viability was examined after seeding MDA-T32 papillary thyroid cancer (PTC) cells onto the decellularized tissues. Decellularized tissues exhibited a notable decrease (<50 ng mg-1DNA, except for Groups 2 and 7) compared to the native thyroid tissue. Nonetheless, collagen and glycosaminoglycans were shown to be conserved in all decellularized tissues. Laminin and fibronectin were preserved at comparatively higher levels, and Young's modulus was elevated when decellularization included SDS. It was observed that the strain value in Group 1 (1.63 ± 0.14 MPa) was significantly greater than that in the decellularized tissues between Groups 2-9, ranging from 0.13 ± 0.03-0.72 ± 0.29 MPa. Finally, viability assessment demonstrated that PTC cells within the recellularized tissue groups successfully attached to the 3D scaffolds and sustained metabolic activity throughout the incubation period. We successfully established a decellularization optimization for human thyroid tissues, which has potential applications in tissue engineering and transplantation research. Our next goal is to conduct recellularization using the methods utilized in Group 1 and transplant the primary thyroid follicular cell-seeded tissues into anin vivoanimal model, particularly due to their remarkable 3D structural preservation and cell adhesion-promoting properties.