After how many passages in monolayer culture do chondrocytes start to de‑differentiate?
Mature articular chondrocytes are post‑mitotic cells that produce extracellular matrix components such as collagen types II, IX, and XI, as well as proteoglycans. After isolation from cartilage and seeding in monolayer culture, chondrocytes re‑enter the cell cycle and begin to proliferate. Following approximately 1-3 weeks in monolayer culture, they gradually start to de‑differentiate and adopt a fibroblast‑like phenotype.
Indicators of de‑differentiation De‑differentiation can be detected by:
Decreased expression of collagen type II
Increased expression of collagen type I
Appearance of the fibroblast marker Thy‑1/CD90
Re‑differentiation
Chondrocyte re‑differentiation can be induced by switching from conventional 2D monolayer culture to a 3D culture system.