FIG. 3.

Chondrogenic differentiation of hBMSCs in a simulated osteochondral environment in vivo is also mediated by subchondral bone. (A) Collagen type 2 and aggrecan gene expression relative to GAPDH of hBMSCs cultured in vitro in alginate beads in complete chondrogenic medium or in alginate in osteochondral biopsies with simulated chondral or osteochondral defects without supplementing TGFβ for 28 days (hBMSCs from 3 donors, n=3 per donor, generalized estimated equations model with correction for multiple testing); (B–D) Osteochondral biopsies with hBMSCs in alginate in simulated osteochondral (B) or chondral (C) defects or controls with osteochondral defects filled with alginate without cells (D) were implanted subcutaneously in nude mice for 12 weeks. Representative safranin-O stained sections, scale bars in upper pictures represent 3 mm, scale bars in magnified pictures represent 400 μm. M, NeuroPatch membrane; NC, native bovine cartilage; NT, newly formed tissue; SB, subchondral bone. GAGs have been lost from the NC during the experiment, most likely due to lack of mechanical stimulation; (E) Quantification of newly formed safranin-O-positive tissue relative to the defect area (hBMSCs from 3 donors, n=3 per donor, generalized estimated equations model with correction for multiple testing); Color images available online at www.liebertpub.com/tea