Micromolar sodium fluoride mediates anti-osteoclastogenesis in Porphyromonas gingivalis-induced alveolar bone loss

Osteoclasts are bone-specific multinucleated cells generated by the differentiation of monocyte/macrophage lineage precursors. Regulation of osteoclast differentiation is considered an effective therapeutic approach to the treatment of bone-lytic diseases. Periodontitis is an inflammatory disease characterized by extensive bone resorption. In this study, we investigated the effects of sodium fluoride （NaF） on osteoclastogenesis induced by Porphyromonas gingivalis, an important colonizer of the oral cavity that has been implicated in periodontitis. NaF strongly inhibited the P. gingivalis-induced alveolar bone loss. That effect was accompanied by decreased levels of cathepsin K, interleukin （IL）-1β, matrix metalloproteinase 9 （MMP9）, and tartrate-resistant acid phosphatase, which were up-regulated during P. gingivalis-induced osteoclastogenesis. Consistent with the in vivo anti-osteoclastogenic effect, NaF inhibited osteoclast formation caused by the differentiation factor RANKL （receptor activator of nuclear factor KB ligand） and macrophage colony-stimulating factor （M-CSF）. The RANKL-stimulated induction of the transcription factor nuclear factor of activated T cells （NFAT） cl was also abrogated by NaF. Taken together, our data demonstrate that NaF inhibits RANKL-induced osteoclastogenesis by reducing the induction of NFATcl, ultimately leading to the suppressed expression of cathepsin K and MMP9. The in vivo effect of NaF on the inhibition of P. gingivalis-induced osteoclastogenesis strengthens the potential usefulness of NaF for treating periodontal diseases.

Toxicity of Sodium Fluoride to Caenorhabditis elegans

Objective To investigate the toxic effect of sodium fluoride（NaF） on the nematode Caenorhabditis elegans（C.elegans）.Methods Adult C.elegans were exposed to different concentrations of NaF（0.038 mmol/L,0.38 mmol/L,and 3.8 mmol/L） for 24 h.To assess the physiological effects of NaF,the brood size,life span,head thrashes,and body bend frequency were examined.Reactive oxygen species（ROS） and cell apoptosis were detected as parameters of biochemical response.The gene expressions were determined by real‐time polymerase chain reaction（PCR） to assess the molecular‐level response.Results At the physiological level,the brood size of C.elegans exposed to 0.038 mmol/L,0.38 mmol/L,and 3.8 mmol/L concentrations of NaF were reduced by 6%,26%,and 28% respectively in comparison with the control group.The maximum life spans of C.elegans exposed to 0.038 mmol/L,0.38 mmol/L,and 3.8 mmol/L concentrations of NaF were reduced by 3 days and 5 days,respectively.Head thrashes and body bend frequency both decreased with increasing concentrations of NaF.At the biochemical level,the production of ROS and the incidence of cell apoptosis increased with increasing concentrations of NaF（P0.05）.At the molecular level,different concentrations of NaF exposure raised the expression of stress‐related genes,such as hsp16.1,sod‐3,ctl‐2,dhs‐28,gst‐1,and cep‐1.Conclusion NaF exposure could induce multiple biological toxicities to C.elegans in a concentration‐dependent manner.These toxicities may be relevant to the oxidative stress induced by increased ROS production and accumulation in C.elegans.

Determination of Trace Iron in High Purity Sodium Fluoride by Graphite Furnace Atomic Absorption Spectrometry

A method is described for the direct determination of iron in high purity sodium fluoride using graphite furnace atomic absorption spectrometry. Interferences caused by the matrix are investigated. It is shown that the ashing temperature can be increased to 1 400°C and matrix interferences eliminated, the sensitivity of iron increased in 1. 27 fold by the addition of nickel nitrate. The method is applied to the determination of iron in sodium fluoride and satisfactory results are obtained.

The leaf extracts of Camellia sinensis (green tea) ameliorate sodium fluoride-induced oxidative stress and testicular dysfunction in rats

Objective:To investigate the effect of Camellia(C.)sinensis in mitigating oxidative damage and reproductive toxicity in testis induced by sodium fluoride in a rat model.Methods:Twenty-four adult male Wister rats were divided into 4 groups,with 6 rats in each group.Group 1 orally received distilled water(1 mL/100 g body weight)daily and served as the control group,while group 2 received drinking water with 100 ppm sodium fluoride per day for 21 consecutive days,group 3 was administered with only C.sinensis extract by gavage at a dose of 100 mg/kg body weight and group 4 received drinking water with 100 ppm sodium fluoride and 100 mg/kg body weight C.sinensis leaf extract per day for 21 consecutive days.At the end of the treatment,the rats were sacrificed under light ether anesthesia.The gonado-somatic index,sperm count and motility,serum level of luteinizing hormone and testosterone were assayed.Lipid peroxidation[malondialdehyde(MDA)level],nitric oxide(NO)production,and activities of antioxidant enzymes-superoxide dismutase(SOD),catalase,and reduced glutathione level(GSH)were also analysed.Results:Sodium fluoride treatment significantly decreased gonado-somatic index,sperm count and motility as well as the serum level of luteinizing hormone and testosterone(P<0.05).The histological examination of testes revealed atrophy and degenerative changes in several seminiferous tubules,along with enhanced interstitial space and a reduced number of Leydig cells.There was a highly significant increase in NO and MDA production(P<0.05),while SOD,catalase activities and GSH level decreased significantly(P<0.05).However,C.sinensis significantly restored testicular weight,sperm parameter,hormonal level(P<0.05),and also reversed MDA and NO generation and antioxidant enzymes activities in the testicular tissue(P<0.05).Conclusions:C.sinensis may have an ameliorative role against sodium fluoride-induced oxidative damage in the testis probably because of its antioxidant property.

Actions of Sodium Fluoride on Acetylcholinesterase Activities in Rats

This study was carried out to observe the effects of sodium fluoride on acetylcholinesterase (AChE) activities in the cerebral synaptic membranes (SPM) and the peripheral red blood cells (RBC) of rats by in vivo and in vitro experiments. In the in vivo study,pregnant rats ingested ad libitum fluorinated drinking water (5, 15, 50 ppm F ) during their gestation and lactation. It was shown that the AChE activities of the SPM and peripheral RBCs in maternal rats exposed 5 ~ 50 ppm F for 60 days were elevated significantly by 30. 0 ~ 67. 6 % and 12. 5 ~ 31. 9 % in a dose-dependent manner, respectively. The AChE activities of their offspring 80 days after birth were also increaased (8. 7 ~ 28. 7 % for SPM and20. 6 ~ 32. 4 % for RBC). In contrast, the AChE activities of SPM in vitro were inhibited by 5. 0~ 50 .0 mmol F /L treatment in a time-and dose dependent manner. Analaysis with the Hanes plots suggested that the enzymesubstrate kinetics are consistent with a mixed type ofinhibition.

Influence of sodium fluoride on alkaline phosphatase activity and bone gla protein synthesis in human yellow ligament cells in vitro

Objective To investigate the influence of sodium fluoride(NaF)on alkaline phosphatase(ALP)activity and bone gla protein(BGP)synthesis in yellow ligament cells from different surgical simples in vitro.Methods The human ligament cells

Sodium fluoride induces apoptosis through reactive oxygen species-mediated endoplasmic reticulum stress pathway in Sertoli cells

Excessive fluoride exposure is known to contribute to reproductive system dysfunction,ultimately leading to pathological damage and apoptosis in cells. Although both oxidative and endoplasmic reticulum（ER） stresses have been implicated in fluorosis, the signaling pathways and their roles in sodium fluoride（Na F）-induced apoptosis of Sertoli cells have been sparsely described. In this study, oxidative damage, ER stress, and apoptosis were analyzed after Sertoli cells were treated with varying doses of Na F for 24 hr. Moreover, the antioxidant N-acetylcysteine（NAC） and pro-apoptotic transcription factor CHOP knockdown were used to clarify the precise interplay between reactive oxygen species（ROS）, ER stress and their roles in NaF-induced apoptosis in Sertoli cells. The present study indicated that NaF significantly decreased cell viability and induced apoptosis in Sertoli cells. In addition, NaF exposure facilitated the accumulation of ROS and increased nuclear translocation of nuclear factor erythroid 2-related factor 2（Nrf2） in Sertoli cells. Treatment with NAC caused remarkable recovery from these NaF-induced responses. Meanwhile, excessive NaF triggered ER stress as evidenced by up-regulated glucose-regulated protein 78 k Da（GRP78）, PKR-like ER kinase（PERK）, phosphorylation of eukaryotic translation initiation factor 2α（p-eI F2α） and CCAAT/enhancer-binding protein-homologous protein（CHOP）, without affecting total eukaryotic translation initiation factor 2α（e IF2α）. NAC effectively blocked the activation of ER stress, suggesting that Na F-induced ROS is an early event that triggers ER stress. Taken together, the results demonstrate that the ROS-mediated ER stress pathway is the crucial mechanistic event involved in NaF-induced apoptosis of Sertoli cells.

Sodium fluoride sacrificing layer concept enables high-efficiency and stable methylammonium lead iodide perovskite solar cells

As next-generation photovoltaic devices,methylammonium lead iodide(MAPbI_(3))-based organic-inorganic halide perovskite solar cells(PSCs)have received considerable attention because of their cost effectiveness and high efficiency.However,their practical applications are retarded due to severe instability under moisture,thermal and sunlight conditions,which are closely related to the insufficient perovskite film quality and high photocatalytic activity of defective TiO_(2) electron-transporting layer(ETL)to accelerate the perovskite decomposition.Herein,remarkably enhanced power conversion efficiency(PCE)and stability of MAPbI_(3)-based PSCs is reached through the use of a new sodium fluoride(NaF)sacrificing layer,which,introduced between the perovskite layer and ETL,is sacrificed during cell fabrication by penetrating into the perovskite layer,improving the perovskite film quality,while partial NaF is incorporated into the mesoporous TiO_(2) ETL during NaF layer fabrication to passivate TiO_(2) and construct a well-matched energy level alignment.As a result,the optimized PSC generates a high PCE of 20.9%,which is 17%higher than that of the pristine cell(17.9%),and outstanding performance stability due to remarkably enhanced moisture,thermal and sunlight stability.This study highlights a simple and effective approach to boost the PCE and durability of MAPbI 3-based PSCs simultaneously,accelerating the commercialization of this technology.

Sodium fluoride as an efficient catalyst for the synthesis of 2,4-disubstituted-1,3-thiazoles and selenazoles at ambient temperature

Sodium fluoride was found to be a simple, mild and efficient catalyst for the synthesis of 2,4- disuhstituted 1,3-thiazoles and selenazoles utilizing phenacyl bromides/3-（2-bromoacetyl）-2H-chro- men-2-one and thioureaJphenylthiourea/selenourea in aqueous methanol at ambient temperature. Analytically pure products are formed within 1-3 rain in excellent yields.

Folic acid protects against fluoride-induced oxidative stress and testicular damage in rats

Objective:To investigate the effects of folic acid on testicular oxidative damage in sodium fluoride-induced male Wistar rats.Methods:A total of 24 male Wistar rats were divided into 4 groups:the control,sodium fluoride(fed with 100 mg/L sodium fluoride through drinking water orally for 21 days),folic acid(36μg/kg body weight/day,orally),and sodium fluoride plus folic acid(received similar dose orally)groups.At the end of 21 days,epididymal sperm parameters,biochemical analysis of testicular tissue,and serum hormonal levels were performed along with histopathological studies.Results:Sodium fluoride intoxication resulted in marked reduction in gonado somatic index,serum luteinizing hormone,and testosterone level along with 3β-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase activities.In addition,reduction in sperm density,as well as loss of sperm motility and sperm viability,were also observed.Besides,increased levels of testicular malondialdehyde,nitrite,interleukin-6 and tumor necrosis factor-α as well as decreased levels of superoxide dismutase and catalase activities and reduced glutathione content were found to be associated with this toxicity.Folic acid co-treatment,on the other hand,could prevent all the sodium fluoride-induced testicular pathophysiology and oxidative stress related parameters.Histological examinations of testicular sections from the experimental rats supported these results.Conclusions:Combining all,this study suggests that being an antioxidant,folic acid plays a beneficial role against fluoride-induced adverse effects on the male reproductive system.

Synthesis and characterization of lanthanide-doped sodium holmium fluoride nanoparticles for potential application in photothermal therapy

Upconversion nanoparticles(UC NPs)in combination with plasmonic materials have great potential for cancer photothermal therapy.Recently,sodium holmium fluoride(NaHoF4)is being investigated for luminescence and magnetic resonance imaging(MRI)contrast agent.Here,we present successful synthesis of excellent quality doped NaHoF4 NPs for possible UC luminescence application and coated for possible photothermal therapy application.Synthesized NaHoF4 nanocrystals were doped with Yb/Er and coated with gold,gold/silica,silver and polypyrrole(PPy).XRD,XPS and TEM were used to determine structure and morphology of the NPs.Strong UC photoluminescence(PL)emission spectra were obtained from the NPs when excited by near-infrared(NIR)light at 980 nm.Cell viability and toxicity of the NPs were characterized using pancreatic and ovarian cancer cells with results showing that gold/silica coating produced least toxicity followed by gold coating.