Exogenous VEGF introduced by bioceramic composite materials promotes the restoration of bone defect in rabbits

This study aimed to investigate the effect of exogenous vascular endothelial growth factor (VEGF) introduced by bioceramic composite materials on jawbone defect. Rabbits were randomly divided into four groups: control, sham, model, and stent. In the model group, holes of jawbone defect were created through surgery. In the stent group, rabbits with jawbone defect were treated with polyether ketone (PEK)/biphasic bioceramic ((PEK-BBC)) composite materials encapsulating VEGF. At 4, 8, and 16 weeks post-operation, HE and Van Gieson staining of jawbones were performed to characterize the repair status of the bone defect. For all time intervals, we found intact bone structures in the control and sham groups and there was no improvement in the bone defect position in the model group. However, in the stent group, we excitingly observed the growth of many osteocytes in the margin of stents at 8 and 16 weeks. RT-PCR, western blot, and immunofluorescence analysis were conducted to investigate the VEGF expression at 4, 8, and 16 weeks post-operation. At 8 weeks, the level of VEGF in the model group was sharply downregulated as compared with the control group (P < .05) and interestingly, the stent group had a much higher level of VEGF than the model group (P < .05). At 16 weeks, the VEGF expression in the model group was further reduced comparing to the control group (P < .05), which was also elevated to a relative high level by the stent treatment (P < .05). As for the sham group, the VEGF level was stable without any difference from the control group at all time intervals. Therefore, exogenous VEGF introduced by bioceramic composite materials promoted the restoration of bone defect in rabbits.