Bone mass increase and mineralization in rats treated with sodium monofluorophosphate (MFP) and sodium fluoride (NaF

BRUN, LUCAS RM; RIGALLI, ALFREDO

Rosario

Congreso; XXIII Reunión Anual de la Asociación Argentina de Osteología y Metabolismo MIneral; 2006

Asociación Argentina de OSteología y Metabolismo MIneral

BONE MASS INCREASE AND MINERALIZATION IN RATS TREATED WITH SODIUM MONOFLUOROPHOSPHATE (MFP) AND SODIUM FLUORIDE (NaF). Brun LRM, Rigalli A. Bone Biology Lab. School of Medicine. Rosario University. Argentina   Fluoride produces differentiation and proliferation of osteoblasts, and as a consequence it increases bone mass. This effect is consequence of fluoride inhibitory effect of an acid phosphatase involved in signalling pathways of growth factors. The quality of bone formed under fluoride stimulus is still open to debate. On the other hand, MFP would act through the described mechanism and probably through another mechanism that involved Wnt cascade. MFP binds to a2-macroglobulin and is cleared from plasma for LRP receptor, which acts together with Frizzled receptor in Wnt signalling. Even though at equivalent doses both drugs induce similar increase in bone mass, after stopping MFP treatment, bone mass remains higher than NaF treated rats. The objective of this work was to study the effect of MFP and NaF on bone mass and mineralization. Female 21-day old rats strain IIM/FM drank for 100 days water with 5 mM NaF (n=40), 5 mM MFP (n=40) or  distilled water (Controls, n=40) drank. Food conversion efficiency (body weigth daily change/daily food intake) and bone mass (weight of whole skeleton, gram) were measured. Mineralization was measured through the relation: weight of bone ashes/weight of dry bone. MFP and NaF treatment did not modify efficiency of animals. Both MFP and NaF treatment increased the asymptotic bone mass (C=9.24±0.3160, MFP= 10.56±0.4529, NaF=10.75±0.5341). Mineralization increased in controls as well as in MFP treated rats, without differences between groups. On the contrary, rats treated with NaF did not show increased in mineralization of bones. Conclusion: MFP produces increased in bone mass without changing mineralization of bone tissue. This results is a another piece of evidence that NaF and MFP has different action mechanism on bone.