Abstract: PURPOSE: To investigate the effects of raloxifene on fracture healing and osteoprotegerin (OPG) / receptor activator of NF-κB ligand (RANKL) / receptor activator of NF-κB (RANK) system in rats with osteoporotic jaw fracture. METHODS: SPF SD rats were used to establish an osteoporotic jaw fracture model. After successful establishment of the model, 12 mg/kg raloxifene were administered intragastrically for 4 weeks. X-ray film was taken to check the fracture healing. Bone mineral density (BMD) was measured by dual energy X-ray absorptiometry. H-E staining was used to examine the morphology of callus. Western blot was used to detect the expression of OPG, RANKL and RANK. SPSS 22.0 software package was used for data analysis. RESULTS: The fracture line recovery of the raloxifene group was better than that of the model group 2 and 4 weeks after surgery. H-E staining showed more bone trabecula and bone matrix-like masses in the callus area than the model group, which was similar to that in blank control group 4 weeks after operation. The BMD and relative expression of OPG protein in raloxifene group were significantly higher than those in model group at 2 and 4 weeks after operation, and the relative expression of RANKL and RANK protein were significantly lower than those in model group (P<0.05), which were similar to those in blank control group 4 weeks after operation (P>0.05). CONCLUSIONS: Raloxifene can regulate OPG/RANKL/RANK system and promote fracture healing in rats with osteoporotic jaw fracture.

Key words: Raloxifene, Osteoporosis, Jaw fracture