Morphological and functional differentiation of human thyroid cells in collagen gel culture

Objective: cultured human thyroid cells in collagen gel culture were examined on cell morphology and the production of thyroglobulin (Tg), triiodothyronine (T3) and thyroxine (T4) which are components of functional differentiation. Methods: thyroid cells obtained from normal human thyroid tissues (four cases), follicular adenoma tissues (three cases), papillary carcinoma tissues (three cases), and follicular carcinoma tissue (one case), were cultured in collagen gel. Then these cultured cells were observed on cellular morphology and production of Tg, T3 and T4. Moreover, changes in morphological characteristics and production of Tg, T3 and T4 induced by addition of thyroid stimulating hormone (TSH) and epidermal growth factor (EGF) to medium in collagen gel culture were determined. Results: normal and tumor cells in collagen gel culture formed colonies and follicles with Tg production, similar to in vivo-like three-dimensional cellular structures and functions. Normal thyroid cells stimulated TSH induced more Tg and produced morphological changes, i.e. enlarged follicular lumens and increased the height of follicular cells, but did not promote cell proliferation. Reversely, normal thyroid cells stimulated with EGF promoted cell proliferation, but did not change morphological findings and did not increase production of Tg, T3 and T4. Conclusion: these findings suggest that collagen gel culture is useful for observing the effects of stimulation by cell growth factor on the morphological and functional differentiation of human thyroid cells.