Chondrogenic differentiation of bMSC isolated from fetal bone marrow. (A) Culture of bMSC under differentiation media during 21 days resulted in cartilage pellet formation. (a) bMSC were differentiated using micromass culture system (b) formed cartilage pellet after 21 days of culture. (c and d) Presence of glycosaminoglycans was confirmed in histological sections of the pellet by alcian blue staining. (B) Levels of ACAN mRNA increased (P < 0.05) in differentiating bMSC at Days 7, 14 and 21compared to untreated controls. In contrast, lower (P < 0.05) levels of NANOG mRNA were detected in differentiating bMSC at Days 7 and 21compared to untreated controls. (C) COL2A1 and (D) SOX9 mRNA levels increased in differentiated bMSC at day 21 of culture. (E) ACAN was immunodetected in cartilage pellet at Day 21 of culture. Phase contrast (PC), ACAN, and merged with DAPI for control (treated with non-immune serum instead of primary antibody) and differentiation bMSC. Data are shown as mean ± standard errors. Superscripts (a, b,*) represent significant (P < 0.05) differences between treatment and sampling days. Bar scale: (b) 2 mm; (c) 200 μm; (d) 100 μm; (C), 500 μm.