Effects of fluoride on rat cancellous bone.

Female Wistar rats were divided into four groups each fed ad libitum regular rodent chow and fluoridated water at four levels (0, 2, 4, 6 mmol/l) for 3 months. There were significant differences in ash weights between control and fluoridated vertebrae (P less than 0.01). Intact bone fluoride (F) values observed were: 0.04 +/- 0.01% fat-free dry weight (ffdw) for control vertebrae and 0.22-0.34 +/- 0.03% ffdw for fluoridated vertebrae. Deproteinized fluoridated vertebral bone had significantly lower specific surface area (SSA) (from 100 +/- 19 m2/g, P less than 0.01, down to 80 +/- 20 m2/g, P less than 0.001) than the control group (120 +/- 10 m2/g); a finding in support of our hypothesis that more of the bone mineral units in fluoridated bone are older (hence denser) than in normal bone. Static morphometric analysis of toluidine blue-stained sections of the femoral metaphyses showed that both cancellous bone volume/tissue volume (Cn-BV/TV) and trabecular thickness (Tb.Th) increased linearly with NaF dosage (R = 0.99 and 0.97, respectively); with Cn-BV/TV increasing from 21 +/- 7 to 33 +/- 6% (P less than 0.01) and Tb.Th from 76 +/- 8 to 98 +/- 9 microns (P less than 0.01). Similar Cn-BV/TV results were also obtained from von Kossa-stained sections.(ABSTRACT TRUNCATED AT 250 WORDS)