[The effect of sodium fluoride on bone mineral density and bone strength in ovariectomized rats]

An experimental study was performed to evaluate the effects of sodium fluoride (NaF) on bone mineral density (BMD) and bone strength in rat. Sixty-nine female Wistar rats aged 12 months were used. Ovariectomy was carried out in 59 rats, and 3 of these were sacrificed to confirm osteopenia at 6 months after the ovariectomy. Twenty-eight of the remaining 56 rats were given NaF. Half of this NaF Group was given high-Ca feed and the other half was given normal feed. And one half of the High-Ca Group and one half of the Normal Feed Group were given vit. D. The other 28 rats in the Non-NaF Group were given high-Ca and vit. D as in the NaF Group. Accordingly, eight groups were created, each with seven rats. All were treated for 9 weeks. An additional 10 rats were used for control. At 6 months after a sham operation, three of these controls were sacrificed to confirm non-osteopenia. The remaining seven controls were given normal feed for 9 weeks. Therefore, there was total of 9 groups (69 rats). At eight months after the surgery (ovariectomy or the sham procedure), both femurs were removed from each rat. The BMD was measured over the entire femur by the DXA method. Bone strength was measured by three-point bending, compression and penetration tests. BMD was found to be higher in the NaF Group than in the Non-NaF Group or Control Group, and was highest in the NaF-high-Ca feed Group. In the bone strength test, the NaF Group scored higher than the Non-NaF Group. In the three-point bending and penetration tests, the NaF-high-Ca feed Group was highest. A linear correlation was found between the BMD and bone strength. There was no effect produced by the administration of the vit. D on the BMD or bone strength. In conclusion, the experimental administration of NaF, and of high-Ca feed, increased BMD and bone strength.