Figure 4. Chondrogenic and osteogenic potential of ALDH^hi myoblasts.

(a–c) Chondrogenic differentiation in ALDH sorted myoblasts was induced via a pellet system containing TGF. Rapid proliferation and chondrogenic pellet formation was observed in ALDH^hi myoblasts (24 hrs) with robust production of glycosaminoglycans (GAGs), visualized via Alcian blue staining. This is in contrast to the poor proliferation and GAG production of ALDH^lo myoblasts. This result suggests that the chondrogenic differentiation capacity of unsorted myoblasts is dominated by ALDH^hi myoblasts. (d–f) Osteogenic differentiation of ALDH sorted myoblasts was induced in vitro by BMP-4 stimulation. Alkaline phosphatase levels (ALP, shown in blue), an early marker of osteogenic differentiation were significantly increased in ALDH^hi myoblasts compared to ALDH^lo myoblasts after a period of 4 d of BMP-4 stimulation.