Effects of α-tocopherol on the early phase of osteoporotic fracture healing

Fracture healing is a complex process, which is more complicated if the bone is osteoporotic. One of the vitamin E isomers, α-tocopherol, has been found to prevent osteoporosis and improve bone fracture healing but its role in the healing of osteoporotic fractures is still unclear. We carried out a study on the effects of α-tocopherol supplementation on osteoporotic fracture healing using an ovariectomized rat model, whereby we focused on the early phase of fracture healing, that is, the phase with excessive production of free radicals. Twenty-four female Sprague-Dawley rats were divided into three groups: sham-operated (SO), ovariectomized-control (OVC), and ovariectomized + α-tocopherol supplementation (ATF) groups. The right femora of all the rats were fractured at mid-diaphysis and K-wires were inserted for internal fixation. After 2 weeks of treatment, the rats were euthanized and the femora were dissected out for measurement of callous volume by CT-scan and radiological staging of callous formation and fracture healing. The oxidative parameters of the fractured femora were also measured. The results showed that the callous volume and callous staging were not different between the groups. However, the fracture healing stage of the OVC group was lower than the SO group, while α-tocopherol supplementation in the ATF group had improved the healing until it was comparable to the SO group. The activities of the anti-oxidatant enzymes, superoxide dismutase, and glutathione peroxidase in the ATF group were found to be significantly higher than in the OVC group. In conclusion, α-tocopherol improved fracture healing but had no effect on the callous volume and staging. The improvement in fracture healing may be due to the increased activities of the anti-oxidatant enzymes in the bone during the early phase of fracture healing of osteoporotic bone.