Fig 1.

Histology of the femoral diaphysis. (A) At 1 day old, the cortical bone (CB) shows a cancellous structure without clear primary osteons. (B) At 2 weeks old, the CB contains many incomplete (ICPO) and complete primary osteons (CPO) with a round osteonal cavity (OC). (C) In the OCs, spindle cells (arrows) localize in the perivascular areas, and cuboidal osteoblasts (arrowheads) line the surface of the CB. (D) At 7 weeks old, the CB shows a compact structure and the OCs are decreased from the outer toward the inner cortical region. (E) At 3 months old, no ICPOs are detected. (F) GSL-I-reactive blood vessels (arrows) are observed in the center of the CPOs and ICPOs. PeO, periosteum; VC, vascular cavity; BM, bone marrow; asterisk, blood vessel. Scale bars: 50 μm. (A–E) HE staining. (F) GSL-I lectin-histochemistry.