Figure 1.

Panel A: preparation steps of primary rat thyroid follicle culture embedded into Matrigel. Rat thyroid tissue was digested with collagenase/dispase mixture; isolated follicles were purified and collected by double filtration through nylon mesh with pore size 200 µm to remove big connective tissue aggregates and 40 µm to eliminate single cells and damaged follicles. Then follicles were recovered from the 40 µm filter and embedded into a growth factor-reduced Matrigel and cultured for 2 weeks in defined medium. Panel B: suspension of intact rat thyroid follicles after double filtration through nylon mesh. Panel C: 12-well plate with drops of polymerized Matrigel, containing embedded thyroid follicles before the addition of growth media. Panel D: rat thyroid follicles embedded into Matrigel after 1 day of cultivation, bar scale:100 µm. Panel E: thyroid follicles in Matrigel after 14 days of cultivation, bar scale: 100 µm.