Figure: Effect of OA-P on bone formation in vivo.
Photomicrographs of H&E stained sections of the diaphysis from control (A) and OA-P (B-D) injected femurs. (A) Low power photomicrograph showing normal cortical bone (cb) and marrow (m) in a saline/BSA-injected control femur. There was no evidence of de novo bone formation anywhere in the marrow cavity. (B) Low power photomicrograph of similar region shown in A, but in OA-P-injected femur showing a large island of newly formed woven bone (outlined by arrows). (C and D) Higher power photomicrographs of bone formed in response to OA-P showing bony trabeculae (t) lined with active osteoblasts. In some areas, especially at the periphery, there are rows of osteoblasts and/or osteoprogenitors piled two or more layers deep (arrows). Note that the marrow (m) immediately adjacent to newly formed bone has an abundance of vascular channels (v). Magnifications: A & B = X60; C = X130; D = X200.