Abstract

Exposure to high levels of fluoride (F-) can result in dental fluorosis in different individuals, but the mechanism of dental fluorosis remains unclear. Autophagy is a highly conserved intracellular digestion process that degrades damaged organelles and protein aggregates. This study examined the effect of sodium fluoride (NaF) on the expression of Beclin1 and mTOR to elucidate the development mechanisms of dental fluorosis. HAT-7 cells were incubated with various concentrations of NaF, and autophagic vacuoles were studied by transmission electron microscopy. At both mRNA and protein level, expression of Beclin1, which is required for autophagosome formation and decreases the expression of mTOR, an autophagy-related complex, was increased at 1.2 mmol/l NaF compared to baseline (0 mmol/l NaF). Additionally, immunohistochemical analysis was performed on paraffin-embedded rat incisor sections to identify the expression of Beclin1 and mTOR proteins in vitro. Highly significant differences were detected compared to controls. In summary, our results demonstrate unequivocally that excessive amounts of fluoride cause autophagy of HAT-7 cells, indicating that autophagy is involved in dental fluorosis.

• Related Studies :

  • Enamel fluorosis related to plasma F levels in the rat.

    The purpose of this long-term study was to investigate disturbances in enamel mineralization associated with low, but relatively constant, plasma fluoride levels produced by constant infusion or with fluctuating plasma fluoride levels caused by drinking fluoridated water. Weanling rats were raised for 8 weeks on low-fluoride food and water containing

  • Stress Response Pathways in Ameloblasts: Implications for Amelogenesis and Dental Fluorosis

    Human enamel development of the permanent teeth takes place during childhood and stresses encountered during this period can have lasting effects on the appearance and structural integrity of the enamel. One of the most common examples of this is the development of dental fluorosis after childhood exposure to excess fluoride,

  • Protective effect of lycopene on fluoride-induced ameloblasts apoptosis and dental fluorosis through oxidative stress-mediated Caspase pathways

    Fluoride is an environmental toxicant and induces dental fluorosis and oxidative stress. Lycopene (LYC) is an effective antioxidant that is reported to attenuate fluoride toxicity. To determine the effects of LYC on sodium fluoride (NaF) -induced teeth and ameloblasts toxicity, rats were treated with NaF (10 mg/kg) and/or LYC (10 mg/kg) by

  • Fluoride induced endoplasmic reticulum stress and calcium overload in ameloblasts

    OBJECTIVE:  The aim of the study was to evaluate the involvement of endoplasmic reticulum stress and intracellular calcium overload on the development of dental fluorosis. METHODS:  We cultured and exposed rat ameloblast HAT-7 cells to various concentrations of fluoride and measured apoptosis with flow cytometry and intracellular Ca2+ changes using confocal

  • Uncoupling protein-2 is an antioxidant that is up-regulated in the enamel organ of fluoride-treated rats

    Dental fluorosis is characterized by subsurface hypomineralization and retention of enamel matrix proteins. Fluoride (F-) exposure generates reactive oxygen species (ROS) that can cause endoplasmic reticulum (ER)-stress. We therefore screened oxidative stress arrays to identify genes regulated by F- exposure. Vitamin E is an antioxidant so we asked if a

• Related FAN Content :

  • Mechanisms by Which Fluoride Causes Dental Fluorosis Remain Unknown

    When it comes to how fluoride impacts human health, no tissue in the body has been studied more than the teeth. Yet, despite over 50 years of research, the mechanism by which fluoride causes dental fluorosis (a hypo-mineralization of the enamel that results in significant staining of the teeth) is not

  • Dental Fluorosis Is a "Hypo-mineralization" of Enamel

    Teeth with fluorosis have an increase in porosity in the subsurface enamel ("hypomineralization"). The increased porosity of enamel found in fluorosis is a result of a fluoride-induced impairment in the clearance of proteins (amelogenins) from the developing teeth. Despite over 50 years of research, the exact mechanism by which fluoride impairs amelogin

  • Severe Dental Fluorosis: Perception and Psychological Impact

    [caption id="attachment_8879" align="aligncenter" width="550"] Severe fluorosis - Photograph by David Kennedy, DDS[/caption] In its severe forms, dental fluorosis causes highly disfiguring brown and black staining of the teeth, which can cause chronic embarrassment and social anxiety for the impacted child. In 1984, a panel from the National Institute of Mental Health (NIMH) warned

  • Dental Fluorosis: The "Cosmetic" Factor

    Any condition that can cause children to be embarrassed about their physical appearance can have significant consequences on their self-esteem and confidence.  Researchers have repeatedly found that "physical appearance [is] the best predictor of self-esteem" in adolescents, (Harter 2000) and that facial attractiveness, particularly the appearance of one's teeth, is a

  • Dental Fluorosis in the U.S. 1950-2004

    Before the widespread use of fluoride in dentistry, dental fluorosis was rarely found in western countries. Today, with virtually every toothpaste now containing fluoride, and most U.S. water supplies containing fluoride chemicals, dental fluorosis rates have reached unprecedented levels. In the 1950s, it was estimated that only 10% of children in