FIG. 4.

Morphologic, molecular, and functional methods were used to evaluate chondrogenic potential of ECM or Plastic expanded hBMSCs in a pellet culture system after a 15-day serum-free chondrogenic induction. (A) Gross appearance (mm), Alcian blue staining for sulfated glycosaminoglycans (GAGs), and immunohistochemistry for collagens I, II, and X; scale bar is 800 μm; (B, C) Western blot was used to evaluate TGF-β RII and phospho-TGF-β RII expression during ECM expansion and subsequent chondrogenic induction in hBMSCs. Chondrogenic markers (collagen II and Sox9) were also evaluated in hBMSC chondrogenic differentiation. β-actin was used as an internal control for protein loading, and (D, E) biomechanical testing for stiffness (N/mm) and Young's modulus (kPa). **p<0.01. Data were shown as average±SD for n=4. Color images available online at www.liebertonline.com/tea