Bone morphometry and differences in bone fluorine containing compounds in rats treated with NaF and MFP

Area of Science:

• Pharmacology
• Biochemistry
• Bone Biology

Background:

• Sodium fluoride (NaF) and sodium monofluorophosphate (MFP) are used to enhance bone mass.
• Previous studies suggested equivalence, but treatment outcomes and mechanisms remain unclear.
• Research often focused on bone mass outcomes, neglecting detailed mechanistic investigations.

Purpose of the Study:

• To investigate the distinct pharmacokinetic and bone incorporation mechanisms of NaF and MFP.
• To compare the effects of NaF and MFP on bone structure and fluoride content in rats.

Main Methods:

• Administration of NaF and MFP to young rats for 30 days.
• Analysis of fluoride distribution in plasma, bone, and excreta.
• Histological and densitometric evaluation of bone tissue, including trabecular and diaphyseal properties.

Main Results:

• Both NaF and MFP significantly increased bone mass, correlating with enhanced trabecular number and thickness.
• MFP treatment resulted in twofold higher bone fluoride content compared to NaF, due to covalently bound fluorine.
• MFP-treated rats exhibited increased femoral diaphysis inertia momentum and unique fluorine binding to alpha-macroglobulin in bone matrix.

Conclusions:

• NaF and MFP exhibit different pharmacokinetic profiles and bone interaction mechanisms.
• MFP promotes greater fluoride accumulation in bone through covalent binding, potentially offering distinct therapeutic benefits.
• The findings highlight the importance of considering drug-specific mechanisms for optimizing bone mass treatments.