Figure 2.

WNT3A in Combination with FGF2 Maintains Robust Chondrogenic Potential of MSCs over Multiple Passages

(A) Schematic of the experimental plan.

(B) Cell-number analysis during MSC expansion. Lines indicate the polynomial regression representatives of the number of WF-MSCs (+WNT+FGF; solid) or F-MSCs (+FGF; dotted). Values represent means ± SEM (n = 3 donors, three to four pellets per donor).

(C and D) MSCs were expanded for up to four passages in the indicated conditions, and pellet cultures were initiated after each passage (n = 3–5 MSC donors each passage, three pellets per donor). Shown are representative sections of the pellets after 5 weeks of chondrogenic induction, stained for glycosaminoglycans (thionine staining). Right: higher magnification of the inset areas. Numbers of cells per mm² are indicated in the right panels (values represent the mean ± SEM of measurements performed in three different pellets from three MSC donors). The scale bars represent 1 mm (left panels) and 200 μm (right panels). Dbs, cell doublings.