The genetic influence on bone susceptibility to fluoride

Introduction: The influence of genetic background on bone architecture and mechanical properties is well established. Nevertheless, to date, only few animal studies explore an underlying genetic basis for extrinsic factors effect such as fluoride effect on bone metabolism. Materials and methods: This study assessed the effect of increasing fluoride doses (0 ppm, 25 ppm, 50 ppm, 100 ppm) on the bone properties in 3 inbred mouse strains that demonstrate different susceptibilities to developing enamel fluorosis (A/J a susceptible strain, 129P3/J a resistant strain and SWR/J an intermediate strain). Fluoride concentrations were determined in femora and vertebral bodies. Bone mineral density was evaluating through DEXA. Finally, three-point bend testing of femora, compression testing of vertebral bodies and femoral neck-fracture testing were performed to evaluate mechanical properties. Results: Concordant with increasing fluoride dose were significant increases of fluoride concentration in femora and vertebral bodies from all 3 strains. Fluoride treatment had little effect on the bone mineral densities (BMD) in the 3 strains. Mechanical testing showed significant alterations in bone quality in the A/J strain, whereas moderate alterations in bone quality in the SWR/J strain and no effects in the 129P3/J strain were observed. Conclusion: The results suggest that genetic factors may contribute to the variation in bone response to fluoride exposure and that fluoride might affect bone properties without altering BMD. (c) 2006 Elsevier Inc. All rights reserved.