FIG. 2.

Effect of gap junction blocking on DNA and GAG synthesis of (a–d) human articular chondrocytes and (e–h) BM-MSCs in alginate hydrogel and micromass pellet cultures. Cells of both types were cultured under identical chondrogenic conditions in the absence (control) or the presence of the gap junction blocker 18-α glycyrrhetinic acid (+18αGCA). The amounts of (a, e) DNA and (b, f) GAG per DNA were measured in constructs collected before (day 0) and at the end of the culture period. The cumulative amount of (c, g) secreted GAG was measured in conditioned media from day 6 and 9 of culture. The (d, h) change in pellet sizes was measured based on photographs taken with a phase-contrast microscope at day 4 and 9 of culture. For clarity, statistical significance was only shown for comparisons between 18αGCA-treated groups and controls or alginate Ctrl versus pellet Ctrl (chondrocytes from three donors: n=7 pellets, n=9 alginate constructs, n=15 pellets for size measurements; MSC from two donors: n=5 pellets or alginate constructs, n=9 pellets from three donors for size measurements). GAG, glycosaminoglycan.