Abstract
Long-term excessive fluoride intake is linked to skeletal disease. Skeletal health is influenced by the balance between bone formation and resorption of which osteoblast function is critical. The objectives of this study were to determine the effect of fluoride treatment on osteoblast proliferation, apoptosis and caspase-3 and caspase-9 mRNA expression in vitro. Neonatal rat osteoblasts were cultured in the presence of varying concentrations (0.5-30 mg/l) of sodium fluoride and effects of treatments were determined. Treatment with sodium fluoride inhibited osteoblast proliferation in a dose-dependent fashion and effects were maximal after 120 h incubation. A significant increase in osteoblast apoptosis was observed (after 24 and 72-h treatment) in response to the lowest dose of sodium fluoride (0.5 mg/l) and osteoblast apoptosis was further increased in response to higher doses. Increased-osteoblast caspase-3 and caspase-9 mRNA was also observed in response to sodium fluoride treatment (5 mg/l) for 72 h. Results indicate that negative effects of excess fluoride on skeletal health may be mediated in part by inhibition of osteoblast survival.
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Experimental fluorosis in rats: NaF induced changes of bone and bone marrow
The results of our experiments suggest that increased doses of NaF cause more extensive osteosclerosis due to the decrease in number and/or activity of osteoclasts. Therefore oateosclerosis is caused primarily, not by increased bone formation but, by the inhibition of bone resorption. This view is supported by the fact that
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Sodium fluoride modulates caprine osteoblast proliferation and differentiation
The cellular and molecular pathways of fluoride toxicity in osteoblasts are not very well understood. Therefore, the objective of the present study was to evaluate the effects of sodium fluoride (NaF) on caprine osteoblasts cultured in vitro. Caprine osteoblasts at 2.0 x 10(-4) cells/ml were incubated in vitro with NaF
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Fluoride promotes osteoblastic differentiation through canonical Wnt/B-catenin signaling pathway
Although fluoride is known to stimulate bone formation, the underlying mechanisms are not fully understood. Recent studies have implicated the Wnt/B-catenin pathway as a major signaling cascade in bone biology. Our earlier studies highlighted a probable role of canonical Wnt pathway in bone formation of chronic fluoride-exposed rats, but the
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Simultaneous administration of fluoride and selenite regulates proliferation and apoptosis in murine osteoblast-like MC3T3-E1 cells by altering osteoprotegerin.
The receptor activator nuclear factor kappa-B ligand (RANKL) and its decoy receptor, osteoprotegerin (OPG), are important for maintaining the balance between bone formation and resorption. However, the regulation of microelements on these factors remains unclear. In this study, we used murine osteoblast-like MC3T3-E1 cells to examine the impact of sodium
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Is the severity of osteosclerosis of fluorosis proportional to the dose of fluoride intake?
Histomorphometric study was made on a series of sections of undecalcified epiphyseal femoral specimens from rats with experimental fluorosis. The results revealed osteosclerosis in Group A (5 ppm) being more severe than that in Group B (25 ppm). With the increase of fluoride dose, the parameters fell down instead of
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Fluoride's Effect on Osteoblasts (Bone-Forming Cells)
As noted by the National Research Council, "[p]erhaps the single clearest effect of fluoride on the skeleton is its stimulation of osteoblast proliferation." (NRC 2006). Osteoblasts are bone-forming cells. "Stimulatory effects of fluoride on osteoblasts result in formation of osteoid, which subsequently undergoes mineralization." (Fisher RL, et al. 1989). If the new
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Skeletal Fluorosis: The Misdiagnosis Problem
It is a virtual certainty that there are individuals in the general population unknowingly suffering from some form of skeletal fluorosis as a result of a doctor's failure to consider fluoride as a cause of their symptoms. Proof that this is the case can be found in the following case reports of skeletal fluorosis written by doctors in the U.S. and other western countries. As can be seen, a consistent feature of these reports is that fluorosis patients--even those with crippling skeletal fluorosis--are misdiagnosed for years by multiple teams of doctors who routinely fail to consider fluoride as a possible cause of their disease.
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"Pre-Skeletal" Fluorosis
As demonstrated by the studies below, skeletal fluorosis may produce adverse symptoms, including arthritic pains, clinical osteoarthritis, gastrointestinal disturbances, and bone fragility, before the classic bone change of fluorosis (i.e., osteosclerosis in the spine and pelvis) is detectable by x-ray. Relying on x-rays, therefore, to diagnosis skeletal fluorosis will invariably fail to protect those individuals who are suffering from the pre-skeletal phase of the disease. Moreover, some individuals with clinical skeletal fluorosis will not develop an increase in bone density, let alone osteosclerosis, of the spine. Thus, relying on unusual increases in spinal bone density will under-detect the rate of skeletal fluoride poisoning in a population.
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Fluoride & Osteoarthritis
While the osteoarthritic effects that occurred from fluoride exposure were once considered to be limited to those with skeletal fluorosis, recent research shows that fluoride can cause osteoarthritis in the absence of traditionally defined fluorosis. Conventional methods used for detecting skeletal fluorosis, therefore, will fail to detect the full range of people suffering from fluoride-induced osteoarthritis.
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Fluoride Increases Osteoid Content of Bone
Fluoride's ability to increase the osteoid content of bone is now undisputed. Osteoid is an unmineralized tissue in bone that, in the normal bone remodeling process, ultimately becomes calcified. As some observers have noted, "[t]he main histological change induced by fluoride is the increase of osteoid volume." (Arnala 1985). One way fluoride
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