INVESTIGADORES
RIGALLI Alfredo
congresos y reuniones científicas
Título:
Effect of sodium fluoride on biomechanical and histomorphometric bone parameters. Identification of variables that determine the fracture load on NaF-treated rats.
Autor/es:
FINA, BRENDA; DA ROS, EUGENIA; ROMA, STELLA MARIS; RIGALLI ALFREDO
Lugar:
Szczecin
Reunión:
Congreso; XXXTH Conference of the International Society for Fluoride Research, advances in fluoride research; 2012
Institución organizadora:
International Society for Fluoride Research
Resumen:
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Osteoporosis
and tooth decay are a public health problem.
For their treatment, sodium
fluoride (NaF) and monofluorophosphate arethe
drugs containing fluoride (F) most commonly used.Disorganization
of bone tissue and presence of inflammatory foci observed when NaF is
administered could be the cause of the lack of effectiveness of F in
the treatment of osteoporosis treatment.The
aim of this work was to evaluate the effect of different F doses on
biomechanical and morphometric properties of trabecular and cortical
bone.
Twenty four Sprague-Dawley rats were divided into 4 groups
(n=6/group): NaF20,
NaF40,
NaF80,
which received orally 20, 40 or 80 µmolNaF/100g bw.day for 30 days;
and Control
thatreceived
water. After
treatment, tibias and femurs were extracted.Histopathological
and histomorphometric parameters were evaluated in the left tibia.
In
the right tibia, bone mineral density (BMD) and cortical parameters
were determined.The
femurs were used for biomechanical tests to evaluate trabecular and
cortical bone properties.Results
are expressed as mean±SEM and differences were considered
significant if p<0.05 (*). Comparisons
were performed using ANOVA test with Bonferroni's post test.
Trabecular
bone volume was significantly decreased by the treatment with F
(Control:23±2;
NaF20:21±2; NaF40:18±1; NaF80:14±2*). Coincidently, we observed a
significant decrease in the trabecular fracture load (N)
(Control:52±11; NaF20:24±4; NaF40:26±6; NaF80:18±4*) and Young´s
Modulus (GPa) (Control:0.16±0.04; NaF20:0.08±0.02;
NaF40:0.07±0.02*; NaF80:0.06±0.02*) of NaF-treated groups. Cortical
bone area (mm2)
decreased significantly in NaF-treated groups (Control:4.1±0.19;
NaF20:4.0±0.14; NaF40:3.8±0.09; NaF80:3.4±0.07*) and
the three point flexural test revealed a significant and a
dose-dependent decrease in cortical bone strength (N) (Control:108±5;
NaF20:100±3; NaF40:87±2*; NaF80:84±4*) and
stiffness (Control:312±38;
NaF20:271±49; NaF40:200±26; NaF80:173±19*).
Apoptosis and inflammation were observed in the trabecular bone of
NaF-treated groups. There were no significant differences in BMD
between the groups. There was a significant correlation between the
fracture load of cortical bone and bone volume, independently of
Young's Modulus. At the trabecular level, fracture load correlated
with Young's Modulus and not with bone volume. These results indicate
that cortical bone depends on the amounts of tissue but trabecular
bone depends on the quality of it.
It
is concluded that chronically administered F as a single daily dose,
produce significant decrease in biomechanical properties of bone by
changing the quality and bone volume although BMD is not affected.