The water-soluble TF3 component from Eupolyphaga sinensis Walker promotes tibial fracture healing in rats by promoting osteoblast proliferation and angiogenesis

Objective: To determine the active components of Eupolyphaga sinensis Walker (Tu Bie Chong) and explore the mechanisms underlying its fracture-healing ability. Methods: A modified Einhorn method was used to develop a rat tibial fracture model. Progression of bone healing was assessed using radiological methods. Safranin O/fast green and CD31 immunohistochemical staining were performed to evaluate the growth of bone cells and angiogenesis at the fracture site. Methylthiazoletetrazolium blue and wound healing assays were used to analyze cell viability and migration. The Transwell assay was used to explore the invasion capacity of the cells. Tubule formation assays were used to assess the angiogenesis capacity of human vascular endothelial cells (HUVECs). qRT-PCR was used to evaluate the changes in gene transcription levels. Results: Tu Bie Chong fraction 3 (TF3) significantly shortened the fracture healing time in model rats. X-ray results showed that on day 14, fracture healing in the TF3 treatment group was significantly better than that in the control group (P = .0086). Tissue staining showed that cartilage growth and the number of H-shaped blood vessels at the fracture site of the TF3 treatment group were better than those of the control group. In vitro, TF3 significantly promoted the proliferation and wound healing of MC3T3-E1s and HUVECs (all P