Longterm cultures of sheep thyroid cells

Area of Science:

• Endocrinology and Cell Biology
• Thyroid Research
• Tissue Engineering

Background:

• Maintaining differentiated thyroid follicular morphology in vitro is challenging.
• Standard thyroid culture systems often fail to preserve follicular structure and function long-term.
• Thyroid-stimulating hormone (TSH) is typically used to support thyroid cell differentiation.

Purpose of the Study:

• To establish a thyroid tissue culture system that preserves follicular morphology for extended periods.
• To investigate the role of medium changes and conditioning in maintaining thyroid cell differentiation and function.
• To quantify the iodide-trapping capacity and proliferation of thyroid cells under various culture conditions.

Main Methods:

• Development of a novel thyroid tissue culture system focusing on follicular morphology preservation.
• Evaluation of culture medium changes and pre-conditioned medium effects on cell viability and differentiation.
• Quantification of iodide (125I--iodide) uptake using a comparative method against a standard cell line (CHO–K1).
• Assessment of cell proliferation and morphology under different culture densities and TSH presence/absence.

Main Results:

• Follicular morphology can be preserved for at least 30 days, with optimal preservation up to 20 days without medium changes.
• Conditioned medium is essential for preserving differentiation beyond 20 days; fresh medium induces dedifferentiation.
• Thyroid cells cultured without medium changes retain iodide-trapping capacity for at least 20 days, even without TSH.
• Primary cultures show limited proliferation, but subculturing at low densities leads to significant proliferation (1-2 day doubling time).

Conclusions:

• A stable thyroid tissue culture system is established, preserving follicular morphology and iodide trapping.
• Medium conditioning, rather than frequent changes, is critical for sustained thyroid cell differentiation in vitro.
• TSH supports morphology and survival but is not strictly required for differentiation or iodide trapping under optimal conditions.