Fig. 1

Bone radiographic and histological findings of rat femur (left: bone radiographic findings, right: histological findings of non-demineralized specimens: toluidine blue staining, × 1). In the C (a) and T(1) groups (b), a fracture line was observed clearly; however, there were no findings of immature or bridging callus formation. In the ZA (c), T(1)+ZA (d), and T(10)+ZA group (e), the fracture line was unclear and mature bridging callus formation was noted. About bone histological imaging (non-demineralized specimens: toluidine blue staining), in the C (a) and T(1) (b) groups, immature callus formation and cartilage tissue were observed; however, in the ZA (c), T(1)+ZA (d), and T(10)+ZA group (e), mature bridging callus formation was noted. Furthermore, bone union was seen resulting from endochondral ossification in the ZA (c), T(1)+ZA (d), and T(10)+ZA group (e), and mature bone tissue was identified in the T(10)+ZA group (e). Ten specimens of one group were divided into two kinds of staining. For the HE staining, 4 of 10 specimens were performed, and for the non-demineralized and toluidine blue staining, 6 of 10 specimens were performed in a random manner