Abstract
Effects of fluoride (as NaF) on cell cycle, DNA content, and apoptosis of mouse fetal long bone cultures were examined and analyzed by flow cytometry (FCM). The results showed that NaF at 2.5–5.0 µg/mL (2.5–5.0 ppm) had only slight effects on the DNA content and cell cycle distributions. At 10.0 µg/mL, however, NaF increased the number of cells in S phase but did not change the frequency of the G0/G1 and G2/M phase. At 20.0 µg /mL NaF not only increased the number of cells in S phase but also decreased the frequency of the G2/M phase. Cell proliferation was also influenced. At 2.5–10.0 µg/mL NaF did not induce increased apoptosis, but the number of apoptotic cells was significantly increased at 20.0 µg NaF/mL. Therefore F damage to bone may involve promoting apoptosis and disordering cell cycle distributions. Although the differences in DNA content, cell cycle distributions, and apoptosis between controls and the two lower NaF concentrations were not statistically significant, there was evidence of hormesis (paradoxical stimulatory) effects. The results indicate that F exerts a dual influence on osteocytes.
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Effect of fluoride on expression of pura gene and CaM gene in newborn rat osteoblasts.
To explore the effect of fluoride (F) on the expression of purine-rich element-binding protein (PURA) gene and calmodulin (CaM) gene in osteoblasts of newborn rats, parietal calvaria bone osteoblast cultures of 48-hr-old rats were treated for 48 hr with sodium fluoride (NaF) at concentrations of 0 (control), 0.5, 2, and
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Different Effects of Fluoride Exposure on the Three Major Bone Cell Types.
Fluoride accumulates and is toxic to bones. Clinical bone lesions occur in a phased manner, being less severe early in the natural course of skeletal fluorosis. Previous research rarely focused on osteocyte, osteoclast, and osteoblast at the same time, although these three types of cells are involved in the process
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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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The pathogenesis of endemic fluorosis: Research progress in the last 5 years.
Fluorine is one of the trace elements necessary for health. It has many physiological functions, and participates in normal metabolism. However, fluorine has paradoxical effects on the body. Many studies have shown that tissues and organs of humans and animals appear to suffer different degrees of damage after long-term direct
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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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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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"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 & Osteoclasts
It is well established that fluoride exposure can increase bone formation by increasing the proliferation of osteoblasts. Less clear is fluoride's impact on bone resorption and the cells (osteoclasts) that resorb bone. Many have assumed that fluoride's main effect on bone resorption and osteoclasts is an inhibitory one (i.e., less
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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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Fluoride & Osteocytes
The osteocyte is a type of bone cell which is increasingly believed to play an important role in repairing defects that arise in bone, thereby maintaining the bone’s structural integrity. Because osteocytes are engulfed in fluoride-rich bone mineral and help resorb the bone as part of the remodeling process, they
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