Figure 5. Ex vivo three-dimensional primary thyroid slice culture.

(A) Thyroid slices were treated with BrdU two hours before harvest at 1, 3, and 7 days after the start of culture. Sections were immunostained for Sca1, BrdU, and NKX2-1 on indicated days. Serial sections were used. Red arrow shows representative Sca1, BrdU, and/or NKX2-1 positive cells. The dotted line in the panel of day 7 BrdU was arbitrarily drawn to separate the central and the peripheral area. They were used to count cell numbers shown in B. Scale bar: 20 µm (Day 1, 3, and 7 upper panel), 50 µm (Day 7 lower panel). (B) Number of Sca1(+) and BrdU(+) cells in primary thyroid slice cultures. Cell numbers were determined based on those obtained after counting 300 intrafollicular (Follicle) or mesenchymal cells (Mesen) in the central (C) or the peripheral (P) area using 10 sections prepared from a culture dish on day 3 and 7. Each dot indicates cell numbers from one culture dish.