RESUMO
This study evaluated the kinetics of fluoride in plasma, femur surface and the whole femur of rats, after chronic exposure to different water fluoride levels was interrupted. Four groups of Wistar rats received drinking water containing 0, 5, 15 or 50 microg F/ml for 60 days (n = 50/group). The animals were euthanized immediately after exposure to fluoride or after 7, 30, 90 or 180 days (n = 10/subgroup). Plasma and femurs were collected. Fluoride on the femur surface, whole femur and plasma was analyzed with an electrode. Data were analyzed using ANOVA and Tukey's test (p< 0.05). The increase in plasma fluoride levels was significant only for the 50 microg F/ml group at 0 and 7 days. Regarding bone surface and whole bone, for most groups, significant increases in fluoride concentrations were observed with the increase in water fluoride concentrations at each time of euthanasia. For fluoride doses up to 15 microg F/ml, femur surface fluoride levels were reestablished 180 days after the exposure was discontinued, which was not valid for whole femur or for higher fluoride doses. We found a different kinetics of fluoride in plasma, femur surface and the whole femur of rats after chronic exposure to fluoride is interrupted.
