The present study was undertaken to determine the fluoride distribution profile with age in the femur of rat.
Fifty-four female Wistar rats were used for the experiment. Six rats were killed under chloroform anesthesia at 4 weeks of age before the experiment. The other forty-eight rats were divided into two groups; one was a control group given distilled water and the other was a fluoride group given water containing 100ppm of fluoride. Six rats from each of the groups were killed at the ages of 6, 12, 24 and 48 weeks.
The fluoride distribution in the cortical thighbone was analyzed from periosteum to the endosteum by abrasive micro-sampling. The results obtained were as follows:
1) The fluoride concentration in the bone of the distilled water drinking group increased slowly with age. The fluoride distribution in the cortical bone was low and flat from the periosteum to the endosteum until the age of 12 weeks.
For the rats in the distilled drinking water group that were aged 24 weeks and older, the fluoride concentration in the periosteum and endosteum was a little higher than in the middle region of the femur.
2) The fluoride concentration in the bone of the rats that drank 100 ppm fluoride containing water increased markedly with age. In the 6 week old fluoride group, the fluoride concentration in the endosteal region was higher than in the periosteal region. The fluoride profile was non-symmetrical.
At the age of 12 weeks, the fluoride concentration in the periosteal region increased gradually.
After the age of 24 weeks, the fluoride profile in the bone changed from a non-symmetrical to a symmetrical U-shaped pattern.
At the age of 48 weeks, the fluoride concentration in the periosteum was significantly higher than in the endosteum.
3) The age-dependent increase in bone fluoride was similar to the age-related increases in body weight and bone length.