| Objective To investigate the effect of regulating the expression of osteoprotegerin (OPG) and receptoractivator of nuclear factor-KB ligand ( RANKL) on early fracture by local application of OPG-Fc to rats with femoral fracture in the process of early fracture, and so as to explore its expression regulation mode and related mechanism. Methods 48 female SD rats were randomly divided into the experimental group and the control group respectively, and 24 pieces per group. And then open fracture model of rats was established, the animals were sacrificed at 4 time points (7, 14, 21 and 28 day) after operation, after callus specimens were sectioned, the information of fracture healing was observed by HE staining and the change of Osteoclast number was detected by immunohistochemical staining. Results HE staining indicated that the process of fracture healing in the pure fracture group was classical, but the callus formation and reforming in the fracture group of local injections of OPG were ahead of schedule, and fracture healing was accelerated. Immunohistochemical staining showed that the osteocyte count values of the pure fracture group were higher than that of the OPG application fracturegroup at all time points of 7, 14, 21 and 28 day, the difference was statistically significant (P<0.05). Conclusion When regulating RANKL expression in the early stage of fracture, with the decreasing of RANKL/OPG, the number of local osteoclast declines, callus formation increases, and fracture healing is accelerated. |