Objective:To explore any effect of mechanical vibration on the expression of estrogen and brain-derived neurotrophic factor (BDNF) in ovariectomized rats with an osteoporotic fracture.Methods:Thirty 3-month-old female Wistar rats were divided randomly into a control group, an ovariectomy group and a vibration group, each of 10. Fractures were induced in the rats of all three groups. Twenty minutes of whole-body vertical vibration was applied to the vibration group at a frequency of 35Hz, 5 days a week for 6 weeks. After 2 and 6 weeks the fracture healing of each group was evaluated using X-rays, the levels of hippocampal estrogen were measured using enzyme-linked immunosorbent assays and fracture-end BDNF was quantified by immunoblotting.Results:After 2 and 6 weeks of vibration the average fracture healing in the vibration group was significantly greater than in the other 2 groups. The average estrogen content in the hippocampus of the vibration group was significantly higher than in the other 2 groups after both 2 and 6 weeks, while the average BDNF content in their fracture ends was significantly lower. The BDNF expression at the fracture end was significantly correlated with the fracture healing.Conclusion:Mechanical vibration can promote the expression of estrogen and BDNF in the hippocampus and accelerate fracture healing in osteoporotic rats.