Objective: To evaluate the effects of XiangLingGuBao (XLGB) on femoral fracture healing in ovariectomized (OVX) rats.
Methods: Forty 12-week-old female SD rats weighing (258 +/- 14) g were divided randomly into 4 groups (n = 10 per group): group A, sham operation by opening the abdominal cavity; group B, bilateral ovariectomy; group C, bilateral ovariectomy, transverse midshaft fracture of the right femur with intramedullary nail fixation, and normal saline by gavage; group D, bilateral ovariectomy, transverse midshaft fracture of the right femur with intramedullary nail fixation, and 250 mg/(kg x d) XLGB by gavage. The weight of rabbits in groups A and B was measured 0, 1, 2, 3, 4 and 5 weeks after operation. The right femur of each rat was obtained 5 weeks after operation. Total femur bone mineral density (tBMD), distal femur bone mineral density (dBMD) and middle femur bone mineral density (mBMD) were measured by double energy X-ray absorptiometry CR filming, HE staining and immunohistochemistry staining of groups C and D were performed.
Results: The weight of rats in group B was obviously higher than that of group A at 3, 4 and 5 weeks after operation (P < 0.05), indicating the animal model of postmenopausal osteoporosis was established successfully. CR films showed more callus and obscure fracture line in group D, while less callus and distinct fracture line in group C. The tBMD and the dBMD of group B were far less than that of group A, the mBMD of group D was significantly higher than that of group C (P < 0.05), the tBMD and the dBMD of group D were higher than that of group C, but no significant difference was evident between two groups (P > 0.05). Histology observation showed, when compared with group C, most fracture ends in group D reached bone union, and the introduction of capillaries was evident in the marrow cavity. Immunohistochemistry staining demonstrated that the BMP-2 integrated absorbance (IA) value in groups C and D was 2.236 6 +/- 0.181 8 and 3.727 3 +/- 0.874 2, respectively, the VEGF IA value in groups C and D was 2.835 5 +/- 0.537 0 and 3.839 6 +/- 0.223 0, respectively, indicating there were significant differences between two groups (P < 0.05).
Conclusion: XLGB can obviously promote the femoral fracture healing in OVX rats, and speed the transformation of woven bone into lamellar bone, which may rely on its role of enhancing expression of BMP-2 and VEGF.