The genetic influence on bone susceptibility to fluoride

Area of Science:

• Skeletal biology
• Toxicology
• Genetics

Background:

• Genetic background significantly impacts bone architecture and mechanical properties.
• Limited research exists on the genetic basis of how extrinsic factors, like fluoride, affect bone metabolism.

Purpose of the Study:

• To investigate the effect of varying fluoride doses on bone properties in three inbred mouse strains with differing susceptibilities to enamel fluorosis.
• To determine if genetic background influences the response to fluoride exposure in bone.

Main Methods:

• Three inbred mouse strains (A/J, 129P3/J, SWR/J) were exposed to increasing fluoride doses (0, 25, 50, 100 ppm).
• Fluoride concentrations in femora and vertebral bodies were measured.
• Bone mineral density (BMD) was assessed using DEXA.
• Mechanical properties were evaluated through three-point bending tests (femora), compression tests (vertebrae), and femoral neck-fracture tests.

Main Results:

• Fluoride concentrations increased in femora and vertebral bodies with higher doses across all strains.
• Fluoride treatment had minimal impact on BMD in the three strains.
• Significant alterations in bone quality were observed in the susceptible A/J strain, moderate alterations in the intermediate SWR/J strain, and no effects in the resistant 129P3/J strain.

Conclusions:

• Genetic factors play a role in the variability of bone response to fluoride exposure.
• Fluoride can affect bone properties, specifically bone quality, independently of changes in BMD.