<p>Hematoxylin and eosin staining (A-L) and azan staining (K, L) on day 7 (A-D), day 14 (E-H) and day 28 (I-L) after osteotomy in rat. (C, D, G, H, K, L) Magnified views of square areas in A, B, E, F, I, J. Histological examination demonstrated that many resorption lacunae were observed on the bone surface at day 7 in the control group (C, arrow and square). In contrast, the cortical bone surface was smooth with few resorption lacunae in BDNF group (D). After day 14, active osteoblasts lined the surface of the BDNF-treated bone (H, arrow and square), although osteoblast differentiation was not prominent in control (G). At day 28, a number of complicated reversal lines were observed in the BDNF-treated bone, and active bone formation occurred not only on the outer surface of the cortical bone but also inside of the bone lacunae and bone marrow cavity as clearly demonstrated by azan staining (L, arrow and square). Bars, 1000 μm (A, B, E, F, I, J), 100 μm (C, D, G, H, K, L).</p
