FIGURE 5.

Chondrogenesis of MSC established from 6- to 8-week-old wild-type and Hmgb2^−/− mice. A, multipotency of bone marrow MSC established from C57Bl/6 wild-type mice. MSC were cultured under conditions to induce chondrogenesis, osteogenesis and adipogenesis as determined by Safranin O (SO), alizarin red S, and Oil Red staining, respectively. B, in chondrogenic pellet cultures, Hmgb2 levels are gradually reduced in wild-type MSC pellets, whereas Col2a1 and Col10a1 are increased. mono, monolayer MSC. C, HMGB2 expression in WT and Hmgb2^−/− (KO) MSC by Western blotting. D, in situ hybridization shows that Col2a1 expression is found extensively in both types of pellets. Col10a1 is expressed exclusively in peripheral areas of wild-type MSC, although Hmgb2^−/− MSC shows high Col10a1 expression throughout. SO, safranin O straining. E, quantitative PCR for Col2a1, Agc1, and Col10a1 expression in wild-type and Hmgb2^−/− MSC at 14 days (14d) pellet culture (*, p < 0.05, n = 4).