Histology: H&E staining. BMP2+EPO and BMP2 groups showed osteoid, blood vessel, and marrow formation at both time points. The BMP2+EPO group had more dense cellular marrow and the BMP2 group had more fatty marrow. b, bone; m, marrow; s, scaffold; f, fibrous tissue; H&E, hematoxylin and eosin. Color images available online at www.liebertpub.com/tec