Figure 1

Delayed dynamic compressive loading improves mechanical properties and extracellular matrix distribution without increasing biochemical content. Following 3 weeks of chondrogenic preculture, dynamic compressive loading was applied daily to human mesenchymal stem cell (MSC)–agarose constructs for 3 weeks. (A) The equilibrium modulus of MSC-seeded constructs was higher in medium containing transforming growth factor beta (TGFβ; CM+) compared with culture without TGFβ (CM–) at 3 and 6 weeks; dynamic loading (DL) in CM + for 3 weeks further improved mechanical properties. (B) Biochemical content of dynamically loaded constructs at week 6 was not different compared with CM + controls. (C) to (E) Alcian Blue staining at week 6 showed equal distribution of proteoglycans between CM + controls and loaded constructs with weak staining in CM– controls. (F) to (H) Picrosirius Red staining and (I) to (K) collagen type II immunostaining showed more homogeneous distribution of collagen in loaded constructs compared with controls. Scale bar: 100 μm. *Greater than CM– controls (P <0.05). **Greater than CM + controls (P <0.05). FS, free swelling. Reproduced from [19] with kind permission from eCM journal [32].