氟和铝在茶型氟中毒大鼠海马神经细胞凋亡中的联合作用及机制
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摘要
目的研究氟和铝在茶型氟中毒大鼠海马神经细胞凋亡中联合作用,探讨其机制。
方法4周龄雄性Sprague Dawley大鼠按体重随机分为5组,即正常对照组、氟组(含F 20.1mg/L)、铝组(含Al 61.9mg/L)、氟+铝组(含F 20.1mg/L,Al 61.9mg/L)、红碎茶组(含F 20.1mg/L,Al 61.9mg/L)。实验期间记录各实验组的饮水量。满6个月时处死动物,取大脑组织甲醛固定,用HE染色和Nissl染色观察大鼠海马结构和形态。用TUNEL法检测各处理组大鼠海马CA_3区椎体神经细胞凋亡的情况;用RT-PCR和免疫组化技术检测海马Bcl-2和Bax mRNA及蛋白表达情况。
结果各实验组饮水量无显著差异。与正常对照组比较,各实验组海马神经细胞凋亡指数明显上升(P＜0.01),其中氟+铝组神经细胞凋亡指数最高,析因方差分析表明,氟和铝对对凋亡指数有交互作用(F=6.38,P＜0.05)。氟、铝联合对Bax mRNA相对表达升高具有协同作用(F=13.05,P＜0.01)。氟、铝单独或同时摄入,均能上调海马BCL-2和BAX在蛋白水平的表达。与正常对照组比较,红碎茶能显著性的上调海马BCL-2和BAX在蛋白水平的表达;红碎茶组的BCL-2和BAX蛋白表达水平显著地低于氟+铝组的。
结论氟、铝协同促进大鼠海马CA_3区神经细胞的凋亡的发生。长期饮用氟、铝浓度相对高的红碎茶水可导致海马神经细胞凋亡,这种神经毒性并不是单独的氟或铝作用的结果,可能与氟、铝联合作用有关。
Objective:To investigate the combined role of fluorine and aluminum on hippocampus neural cell apoptosis in rats induced by drinking black tea fluorosis.Metholds:4-week male Sprague Dawley rats were randomized into 5 group according to their body weight:control group,fluoride treated group(20.1mg/L F as NaF),aluminum treated group(61.9mg/L Al as AlCl_3), fluoride with aluminum treated group(20.1mg/L F and 61.9mg/L Al),and black-tea treated group(20.1mg/L F and 61.9mg/L Al).The experiment lasted for 6 months.Histological sections of hippocampus were stained with hematoxylin & eosin(H&E),Cresyl violet(Nissl stain).TUNEL was used to detect apoptosis of hippocampus neural cells.And the mRNA and protein expression of Bcl-2 and Bax in the hippocampus were determined by RT-PCR and immunohistochemistry techniques.
Results:No differences were found between the water intake of rats in the different treatment groups.Compared with the control group,the hippocampus neural cell apoptosis index was higher in every experiment group(P＜0.01) and fluoride with aluminum treated group was the highest in all groups.Fluorine and aluminum have an interaction on the hippocampus neural cell apoptosis(F=6.38, P＜0.05).The combination of fluorine with aluminum had a synergistic effect on the relative mRNA levels of Bax(F=13.05,P＜0.01).Fluorine and aluminum, solely or simultaneity ingested,could upregulate the protein expression of BCL-2,BAX in hippocampus neural cells.The protein expressin of BCL-2 and BAX were significantly inscreased in black-tea treated group as compared to control grouo.When compared with fluoride with aluminum treated group,the protein expressin of BCL-2 and BAX were significantly descreased.
Conclusions:To some degree,combination of fluorine with aluminum promotes the neural cell apoptosis in CA_3 sector of the hippocampus of rats.The prolonged oral ingestion of black-tea liquor containing a relative high of fluorine and aluminum,could lead to apoptosis,and some of the toxicity seemingly associated with F or Al may be due to the effect of an Al-F complex.
方法4周龄雄性Sprague Dawley大鼠按体重随机分为5组,即正常对照组、氟组(含F 20.1mg/L)、铝组(含Al 61.9mg/L)、氟+铝组(含F 20.1mg/L,Al 61.9mg/L)、红碎茶组(含F 20.1mg/L,Al 61.9mg/L)。实验期间记录各实验组的饮水量。满6个月时处死动物,取大脑组织甲醛固定,用HE染色和Nissl染色观察大鼠海马结构和形态。用TUNEL法检测各处理组大鼠海马CA_3区椎体神经细胞凋亡的情况;用RT-PCR和免疫组化技术检测海马Bcl-2和Bax mRNA及蛋白表达情况。
结果各实验组饮水量无显著差异。与正常对照组比较,各实验组海马神经细胞凋亡指数明显上升(P＜0.01),其中氟+铝组神经细胞凋亡指数最高,析因方差分析表明,氟和铝对对凋亡指数有交互作用(F=6.38,P＜0.05)。氟、铝联合对Bax mRNA相对表达升高具有协同作用(F=13.05,P＜0.01)。氟、铝单独或同时摄入,均能上调海马BCL-2和BAX在蛋白水平的表达。与正常对照组比较,红碎茶能显著性的上调海马BCL-2和BAX在蛋白水平的表达;红碎茶组的BCL-2和BAX蛋白表达水平显著地低于氟+铝组的。
结论氟、铝协同促进大鼠海马CA_3区神经细胞的凋亡的发生。长期饮用氟、铝浓度相对高的红碎茶水可导致海马神经细胞凋亡,这种神经毒性并不是单独的氟或铝作用的结果,可能与氟、铝联合作用有关。
Objective:To investigate the combined role of fluorine and aluminum on hippocampus neural cell apoptosis in rats induced by drinking black tea fluorosis.Metholds:4-week male Sprague Dawley rats were randomized into 5 group according to their body weight:control group,fluoride treated group(20.1mg/L F as NaF),aluminum treated group(61.9mg/L Al as AlCl_3), fluoride with aluminum treated group(20.1mg/L F and 61.9mg/L Al),and black-tea treated group(20.1mg/L F and 61.9mg/L Al).The experiment lasted for 6 months.Histological sections of hippocampus were stained with hematoxylin & eosin(H&E),Cresyl violet(Nissl stain).TUNEL was used to detect apoptosis of hippocampus neural cells.And the mRNA and protein expression of Bcl-2 and Bax in the hippocampus were determined by RT-PCR and immunohistochemistry techniques.
Results:No differences were found between the water intake of rats in the different treatment groups.Compared with the control group,the hippocampus neural cell apoptosis index was higher in every experiment group(P＜0.01) and fluoride with aluminum treated group was the highest in all groups.Fluorine and aluminum have an interaction on the hippocampus neural cell apoptosis(F=6.38, P＜0.05).The combination of fluorine with aluminum had a synergistic effect on the relative mRNA levels of Bax(F=13.05,P＜0.01).Fluorine and aluminum, solely or simultaneity ingested,could upregulate the protein expression of BCL-2,BAX in hippocampus neural cells.The protein expressin of BCL-2 and BAX were significantly inscreased in black-tea treated group as compared to control grouo.When compared with fluoride with aluminum treated group,the protein expressin of BCL-2 and BAX were significantly descreased.
Conclusions:To some degree,combination of fluorine with aluminum promotes the neural cell apoptosis in CA_3 sector of the hippocampus of rats.The prolonged oral ingestion of black-tea liquor containing a relative high of fluorine and aluminum,could lead to apoptosis,and some of the toxicity seemingly associated with F or Al may be due to the effect of an Al-F complex.
引文
[1]Cheng TO.Will green tea be even better than black tea to increase coronary flow velocity reserve?[J].Am J Cardiol,2004,94:1223.
[2]Vinson JA.Black and green tea and heart disease:a review[J].Biofactors,2000,13:1272132.
[3]Anh YJ,Kawamura T,Kim M,et al.Tea polyphenols:Selective growth inhibitors of Clostridium spp[J].Agric Biol Chem,1991,55,1425-1426.
[4]Lin Y L,Lin JK.(-)-Epigallocatechin-3-gallate blocks the induction of nitric oxide synthase by down-regulating lipopolysaccharide-induced activity of transcription factor NF-κβ[J].Mol Pharmacol,1997,52,465-472.
[5]Wang ZY,Cheng S J,Zhou ZC,et al.Anti- mutagenic activity of green tea polyphenols [J].Mutat Res,1989,223,273-285.
[6]Ho CT,Chen Q,Shi-Zhang KQ,et al.Antioxidative effect ofpolyphenol extract prepared from various Chinese teas[J].Pre Med,1992,21,520-525.
[7]Kavanagh KT,Hafer L J,Kim DW,et al.Green tea extracts decrease carcinogen -induced mammary tumor burden in rats and rate of breast cancer cell proliferation in culture[J].J Cell Bioehem,2001,82,387-398.
[8]Katiyar SK,Perez A,Mukhatar H.Green tea polyphenol treatment to human skin prevents formation of ultraviolet light B-induced pyrimidine dimmers in DNA[J].Clin Cancer Res,1999,33,441-445.
[9]Chisaka T,Matsuda H,Kubomura Y,et al.The effect of crude drugs on experimential hypereholesteremia:mode of action of(-)-epigalloeateehine gallate in tea leaves[J].Chem Pharm Bull,1988,36,227-233.
[10]Muramatsu K,Fukuyo M,Hara Y.Effect of green tea eateehine on plasma cholesterol level in cholesterol-fed rats[J].J Nutr Sei Vitaminol,1986,32,613-622.
[11]Lu Y,Guo WF,Yang XQ.Fluoride eonent in tea and its relationship with tea quality [J].J Agric Food Chem,2004,52:4472-4476.
[12]王旭伟(中华人民共和国商务部).中国茶叶对英国出口情况及面临的困难.www.all tea.com,2004,1:14.
[13]Cao J,Zhao Y,Li Y,et al.Fluoride levels in various black tea commodities:Measurement and safety evaluation[J].Food and Chemical Toxicology,2006,44:1131-1137.
[14]Cao J,Zhao Y,Liu JW,et al.Varied Ecological Environment and Fluorosis in Tibetan Children in the Nature reserve of Mount Qomolangma[J].Food and Chemical Toxicology.2001,39,959-962.
[15]Cao J,Zhao Y,Liu JW,et al.Prevention and control of brick-tea type fluorosis- a 3-year observation in Dangxiong,Tibet[J].Econtoxicology and environmental safety,2003,56,222-227.
[16]王劲.铝的生物学作用研究概况[J].卫生研究,2002,31:320-322.
[17]Grapper DR.Brain aluminum in Alzheimer's disease and experimental neurofibrillary degeneration.Science,1973,180:511.
[18]Exley C.A molecular mechanism of aluminium-induced Alzheimer's disease[J].J Inorg Biochem,1999,76:133-140.
[19]Murayama H,Shin RW,Higuchi J,et al.Interaction of aluminum with PHF-tau in Alzheimer disease neurofibrillary degeneration evidenced by desferrioxamine-assiated chelating autoclave method[J].Am J Pathol,1999,155:877-885.
[20]Nagata T,Hayatsu M,Kosuge N.Identification of Aluminum Forms In Tea By A1-27NMR[J].Phytochemistry,1992,31:1215-1218.
[21]Rengel Z.Aluminium cycling in the soil-plant-animal-human continuum[J].BioMetals,2004,17:669-689.
[22]Erdemoglu SB,Turkdemir H,Gucer S.Determination of total and fluoride bound aluminium in tea infusions by ion selective electrode and flame atomic absorption spectrometry[J].Anal Lett,2000,33,1513-1529.
[23]Liang Li.The biochemistry and physiology of metallic fluoride:action,mechanism,and implications[J].Crit Rev Oral Med,2003,14:100-113.
[24]Shu WS,Zhang ZQ,Lan CY,et al.Fluoride and aluminium concentrations of tea plants and tea products from Sichuan Province[J].PR China Chemosphere,2003,52:1475-1482.
[25]Lu YI,Guo WF,Yang XQ.Fluoride Content in Tea and Its Relationship with Tea Quality[J].J.Agric.Food Chem,2004,52:4472-4476.
[26]Lung SC,Hsiao PK,Chiang KM.Fluoride concentrations in three types of commercially packed tea drinks in Taiwan[J].Journal of Exposure Analysis and Environmental Epidemilolgy,2003,13:66-73.
[27]孙殿军,刘立志.我国饮茶型氟中毒研究的回顾及展望[J].中国地方病学杂志,2005,24:1-2.
[28]Cao J,Zhao Y,Liu JW.Brick tea consumption as the cause of dental fluorosis among children from Mongol,Kazal and Yugu populations in China[J].Food and Chemical Toxicology,1997,35:827-833.
[29]Michael P,Whyte MD,Kevan MS,et al.Skeletal fluorosis and instant tea[J].Am J Med,2005,118:78-82.
[30]李广生,徐辉.当前氟中毒机制研究中的几个问题[J].中国地方病学杂志,2006,25:119-120.
[31]吕晓红,李广生,孙波.慢性氟中毒大鼠神经细胞凋亡的研究[J].中国地方病学杂志,2000,19:96-98.
[32]Isaacson RL,Varner JA,Jensen KF.Toxin-induced blood vessel inclusions caused by the chronic administration of aluminum and sodium fluoride and their implications for dementia[J].Ann NY Acad Sci.1997,825:152-166.
[33]Varner JA,Jensen KF,Horvath W,et al.Chronic administration of aluminum-fluoride or sodium-fluoride to rats in drinking water:alterations in neuronal and cerebrovascular integrity[J].Brain Res.1998,784:284-298.
[34]Thompson CB.Apoptosis in the pathogenesis and treatment of disease[J].Science,1995,267:1456-1462.
[35]Verma RJ,Trivedi MH,Chinoy NJ.Black tea amelioration of sodium fluoride-induced alterations of DNA,RNA,and protein contents in the cerebral hemisphere,cerebellum,and medulla oblongata regions of mouse brain[J].Fluride,2007,40:7-12.
[36]Sava VM,Yang SM,Hong MY,et al.Isolation and characterization of melanic pigments derived from tea and tea polyphenols[J].Food Chemistry,2001,73:177-184.
[37]Douglas RG,John CR.Mitochondria and apoptosis[J].Science,1998,281:1309.
[38]Yang B,Rchard A.Expression ofbax,bcl-2 and p53 in progressive multifold leukoencephslopathy[J].Mod Pathol,2000,13:1115-1120.
[39]Shibata M,Murray M,Tessler A,et al.Single injections ofa DNA plasmid that contains the human bcl-2 gene prevent loss and atrophy of distinct neuronal populations after spinal cord injury in adult rats[J].Neurorehabil Neural Repair,2000,14:319-330.
[40]Gazzaniga P,Gradilone A,Vercillo R,et al.Bcl-2/Bax mRNA expression ration as prognostic factor in low-grade urinary bladder cancer[J].Ini J Cancer,1996,69:100-102.
[41]Tsujimoto Y,Cossman J,Jaffe E,et al.Involvement of the bcl-2 gene in human follicular lymphoma [J]. Science, 1985, 228(4706):456-461.
[42] Chen J, Graham SH, Nakayama M, et al. Apoptosis repressor genes Bcl-2 and Bcl-x-long are expressed in the rat brain following global ischemia [J]. J Cereb Blood Flow Metab, 1997,17(1):2-10.
[43] Oltvai ZN, Milliman CL, Korsmeger SJ, et al. Bcl-2 heterodimeriaes in vivo with a conserved homloge, bax, that accelerates programmed cell death [J]. Cell, 1993, 74: 609-613.
[44] Lok J, Martin LJ. Rapid subcellular redistribution of Baxprecdes caspase-3 and endonuclear activation during excitoxic neuronal apoptosis in tar brain [J].Neurotrauma, 2002,19(7):815-825.
[45] Yang MS, Wong MH. Changes in Ca, Cu, Fe, Mg, and Zn Contents in Mouse Brain Tissues After Prolonged Oral Ingestion of Brick Tea Liquor Containing a High Level of Al [J]. Hunana Press Inc, 2001, 80:67-76.
[46] Mattson MP, Lovell MA, Ehmann WD, et al. Comparison of the effects of elevated intracellular aluminum and calcium levels on neuronal survival and tau immunore -activity [J]. Brain Res.1993,29:21-31.
[1]Gilman AG.G proteins:transducers of receptor- generated signals[J].Annu Rev Biochem.1987,56:615-649.
[2]Bigay J,Deterre P,Pfister C,et al.Fluoride complexes of aluminium or beryllium act on G-proteins as reversibly bound analogues of the gamma phosphate ofGTP[J].EMBO J.1987,6:2907-2913.
[3]Chabre M.Aluminofluoride and beryllofluoride complexes:new phosphate analogs in enzymology[J].Trends Biochem Sci.1990,15:6-10.
[4]Li L,Fleming N.Aluminum fluoride inhibition of cabbage phospholipase D by a phosphate-mimicking mechanism[J].FEBS Lett 1999,461(1-2):1-5.
[5]Li L,Fleming N.Aluminum fluoride inhibits phospholipase D activation by a GTP-binding protein- independent mechanism[J].FEBS Lett.1999,458(3):419-423.
[6]Rall TW,Sutherland EW,Berthet J.The relationship of epinephrine and glucagon to liver phosphorylase.Ⅳ.Effect of epinephrine and glucagons on the reactivation of phosphorylase in liver homogenates[J].J Biol Chem 1957,224:463-475.
[7]Rail TW,Suthedand EW.Formation of a cyclic adenine ribonucleotide by tissue particles [J].J Biol Chem.1958,232:1065-1076.
[8]Rodbell M,Bimbaumer L,Pohl SL,et al.The glucagon-sensitive adenyl cyclase system in plasma membranes of rat liver.Ⅴ.An obligatory role of guanylnucleotides in glucagon action[J].J Biol Chem.1971,246:1877-1882.
[9]Ross EM,Gilman AG.Resolution of some components of adenylate cyclase necessary for catalytic activity[J].J Biol Chem.1977,252:6966-6969.
[10]Sternweis PC,Gilman AG.Reconstitution of catecholaminesensitive adenylate cyclase.Reconstitution of the uncoupled variant of the $40 lymphoma cell[J].J Biol Chem.1979,254:3333-3340.
[11]Sternweis PC,Gilman AG.Aluminum:a requirement for activation of the regulatory component of adenylate cyclase by fluoride[J].Proc Natl Acad Sci.1982,79:4888-4891.
[12]Fung BK,Hurley JB,Stryer L.Flow of information in the light-triggered cyclic nucleotide cascade of vision[J].Proc NatlAcad Sci.1981,78:152-156.
[13]Sitaramayya A,Virmaux N,Mandel P.On the mechanism of light activation of retinal rod outer segments cyclic GMP phosphodiesterase(light activation-influence of bleached rhodopsin and KF-deinhibition) [J]. Exp Eye Res. 1977,25:163-169.
[14] Stein PJ, Halliday KR, Rasenick MM. Photoreceptor GTP binding protein mediates fluoride activation of phosphodiesterase[J].J Biol Chem. 1985, 260: 9081- 9084.
[15] Kanaho Y, Moss J, Vaughan M . Mechanism of inhibition of transducin GTPase activity by fluoride and aluminum [J]. J Biol Chem. 1985, 260: 11493-11497.
[16] Bigay J, Deterre P, Pfister C, et al. Fluoroaluminates activate transducin-GDP by mimicking the gamma- phosphate of GTP in its binding site [J]. FEBS Lett. 1985,191:181-185.
[17] Goldstein G . Equilibrium distribution of metal-fluoride complexes [J]. Anal Chem. 1964,36:243-244.
[18] Bigay J, Deterre P, Pfister C, et al. Fluoride complexes of aluminium or beryllium act on G-proteins as reversibly bound analogues of the gamma phosphate of GTP [J]. EMBO J.1987, 6:2907-2913.
[19] Higashijima T, Ferguson KM, Sternweis PC, et al. The effect of activating ligands on the intrinsic fluorescence of guanine nucleotide-binding regulatory proteins[J].J Biol Chem. 1987,262:752-756.
[20] Higashijima T, Graziano MP, Suga H, et al. ~(19)F and ~(31)P NMR spectroscopy of G protein alpha subunits. Mechanism of activation by Al~(3+) and F" [J]. J Biol Chem. 1991,266:3396-3401.
[21] Chabre M. Aluminofluoride and beryllofluoride complexes: new phosphate analogs in enzymology [J].Trends Biochem Sci. 1990,15:6-10.
[22] Knowles AR. Enzyme-catalyzed phosphoryl transfer reactions[J]. Annu Rev Biochem. 1980,49:877-919.
[23] Lolis E, Petsko GA. Transition-state analogues in protein crystallography: probes of the structural source of enzyme catalysis [J]. Annu Rev Biochem. 1990,59:597-630.
[24] Thompson PR, Cole PA. Probing the mechanism of enzymatic phosphoryl transfer with a chemical trick [J]. Proc Natl Acad Sci. 2001,98:8170-8171.
[25] Coleman DE, Sprang SR. Reaction dynamics of G-protein catalyzed hydrolysis of GTP as viewed by x-ray crystallographic snapshots of Gial [J]. Meth Enzymol. 1999,308:70-92.
[26] Rodbell M . The complex regulation of receptor- coupled Gproteins [J].Adv Enzyme Regul. 1997, 37:427-435.
[27] Feuerstein J, Goody RS, Webb MR. The mechanism of guanosine nucleotide hydrolysis by p21 c-Ha-Ras. The stereochemical course of the GTPase reaction [J]. J Biol Chem. 1989,264:6188-6190.
[28]Noel JP,Hamm HE,Sigler PB.The 2.2(?) crystal structure of transducin-alpha complexedwith GTPyS[J].Nature.1993,366:654-663.
[29]Coleman DE,Berghuis AM,Lee E,et al.Structures of active conformations of Gial and the mechanism of GTP hydrolysis[J].Science.1994,265:1405-1412.
[30]Kleuss C,Raw AS,Lee E,et al.Mechanism of GTP hydrolysis by G-protein a subunits [J].Proc Natl Acad Sci.1994,91:9828-9831.
[31]Sondek J,Lambright DG,Noel JP,et al.GTPase mechanism of G proteins from the 1.7-(?) crystal structure of transducin a-GDP-AIF_4~-[J].Nature.1994,372:276-279.
[32]Sprang SR.G protein mechanisms:insights from structural analysis[J].Annu Rev Biochem.1997,66:639-678.
[33]Priest ND.The bioavailability and metabolism of aluminium compounds in man[J].Proc Nutr Soc.1993,52:231-240.
[33]WHO/IPCS.Aluminmun[J].environ health critenia 1997.194,1 - 152.
[35]Ringe JD,Rovati LC.Treatment of osteoporosis in men with fluoride alone or in combination with bisphosphonates[J].CalcifTissue Int.2001,69:252-255.
[36]Whitford GM.The physiological and toxicological characteristics of fluoride[J].J Dent Res.1990:539-549;discussion 556-557.
[37]He H,Ganapathy V,Isales CM,et al.PH-dependent fluoride transport in intestinal brush border membrane vesicles[J].Biochim Biophys Acta.1998,1372:244-254.
[38]WHO.Fluorides and Human Health[M].Geneva,1984.
[39]Martin RB.Aluminum:a neurotoxic product of acid rain[J].Accts Chem Res.1994,27:204-210.
[40]Martin RB.Ternary complexes of Al~(3+) and F~- with a second ligand[J].Coord Chem Rev.1996,149:23-32.
[41]Yu P,Phillips BL,Casey WH.Water exchange in fluoroaluminate complexes in aqueous solution:a variable temperature multinuclear NMR study[J].Inorg Chem.2001,40:4750-4754.
[42]Still CN,Kelley P.On the incidence of primary degenerative dementia vs.water fluoride content in South Carolina[J].Neurotoxicology.1980,1:125-131.
[43]Forbes WF,Agwani N.A suggested mechanism for aluminum biotoxicity[J].J Theoret Biol.1994,171:207-214.
[44]Cowburn RF,O'Neill C,Bonkale WL,et al.Receptor-G-protein signalling in Alzheimer's disease[J].Biochem Soc Symp.2001,67:163-175.
[45] Isaacson RL, Vamer JA, Jensen KF. Toxin-induced blood vessel inclusions caused by the chronic administration of aluminum and sodium fluoride and their implications for dementia [J]. Ann NY Acad Sci. 1997, 825:152-166.
[46] Varner JA, Jensen KF, Horvath W, et al. Chronic administration of aluminum-fluoride or sodium-fluoride to rats in drinking water: alterations in neuronal and cerebrovascular integrity [J]. Brain Res. 1998, 784:284-298.
[47] Farley JR, Wergedal JE, Baylink DJ. Fluoride directly stimulates proliferation and alkaline phosphatase activity of boneforming cells [J]. Science. 1983,222: 330-332.
[48] Caverzasio J, Imai T, Ammann P, et al. Aluminum potentiates the effect of fluoride on tyrosine phosphorylation and osteoblast replication in vitro and bone mass in vivo [J]. J Bone Miner Res. 1996,11: 46-55.
[49] Caverzasio J, Palmer G, Suzuki A,et al. Mechanism of the mitogenic effect of fluoride on osteoblast-like cells: evidences for a G protein-dependent tyrosine phosphorylation process [J]. J Bone Miner Res. 1997,12:1975-1983.
[50] Lau KH, Goodwin C, Arias M, et al. Bone cell mitogenic action of fluoroaluminate and aluminum fluoride but not that of sodium fluoride involves up regulation of the insulin-like growth factor system [J]. Bone. 2002, 30:705-711.
[51] Matsuo S, Kiyomiya K, Kurebe M. Mechanism of toxic action of fluoride in dental fluorosis: whether trimeric G proteins participate in the disturbance of intracellular transport of secretory ameloblast exposed to fluoride [J]. Arch Toxicol. 1998, 72:798-806.
[52] Spencer H, Kramer L, Norris C, et al.Osteoporosis: calcium, fluoride, and aluminum interactions [J]. J Am Coll Nutr. 1985,4:121-128.
[53] Nagata T, Hayatsu M, Kosuge N. Aluminium kinetics in the tea plant using ~(27)A1 and ~(19)F NMR [J].Phytochemistry, 1993, 32: 771-775.
[54] Erdemoglu SB, Turkdemir H, Gucer S. Determination of total and fluoride bound aluminium in tea infusions by ion selective electrode and flame atomic absorption spectrometry [J]. Anal Lett. 2000,33,1513-1529.
[2]Vinson JA.Black and green tea and heart disease:a review[J].Biofactors,2000,13:1272132.
[3]Anh YJ,Kawamura T,Kim M,et al.Tea polyphenols:Selective growth inhibitors of Clostridium spp[J].Agric Biol Chem,1991,55,1425-1426.
[4]Lin Y L,Lin JK.(-)-Epigallocatechin-3-gallate blocks the induction of nitric oxide synthase by down-regulating lipopolysaccharide-induced activity of transcription factor NF-κβ[J].Mol Pharmacol,1997,52,465-472.
[5]Wang ZY,Cheng S J,Zhou ZC,et al.Anti- mutagenic activity of green tea polyphenols [J].Mutat Res,1989,223,273-285.
[6]Ho CT,Chen Q,Shi-Zhang KQ,et al.Antioxidative effect ofpolyphenol extract prepared from various Chinese teas[J].Pre Med,1992,21,520-525.
[7]Kavanagh KT,Hafer L J,Kim DW,et al.Green tea extracts decrease carcinogen -induced mammary tumor burden in rats and rate of breast cancer cell proliferation in culture[J].J Cell Bioehem,2001,82,387-398.
[8]Katiyar SK,Perez A,Mukhatar H.Green tea polyphenol treatment to human skin prevents formation of ultraviolet light B-induced pyrimidine dimmers in DNA[J].Clin Cancer Res,1999,33,441-445.
[9]Chisaka T,Matsuda H,Kubomura Y,et al.The effect of crude drugs on experimential hypereholesteremia:mode of action of(-)-epigalloeateehine gallate in tea leaves[J].Chem Pharm Bull,1988,36,227-233.
[10]Muramatsu K,Fukuyo M,Hara Y.Effect of green tea eateehine on plasma cholesterol level in cholesterol-fed rats[J].J Nutr Sei Vitaminol,1986,32,613-622.
[11]Lu Y,Guo WF,Yang XQ.Fluoride eonent in tea and its relationship with tea quality [J].J Agric Food Chem,2004,52:4472-4476.
[12]王旭伟(中华人民共和国商务部).中国茶叶对英国出口情况及面临的困难.www.all tea.com,2004,1:14.
[13]Cao J,Zhao Y,Li Y,et al.Fluoride levels in various black tea commodities:Measurement and safety evaluation[J].Food and Chemical Toxicology,2006,44:1131-1137.
[14]Cao J,Zhao Y,Liu JW,et al.Varied Ecological Environment and Fluorosis in Tibetan Children in the Nature reserve of Mount Qomolangma[J].Food and Chemical Toxicology.2001,39,959-962.
[15]Cao J,Zhao Y,Liu JW,et al.Prevention and control of brick-tea type fluorosis- a 3-year observation in Dangxiong,Tibet[J].Econtoxicology and environmental safety,2003,56,222-227.
[16]王劲.铝的生物学作用研究概况[J].卫生研究,2002,31:320-322.
[17]Grapper DR.Brain aluminum in Alzheimer's disease and experimental neurofibrillary degeneration.Science,1973,180:511.
[18]Exley C.A molecular mechanism of aluminium-induced Alzheimer's disease[J].J Inorg Biochem,1999,76:133-140.
[19]Murayama H,Shin RW,Higuchi J,et al.Interaction of aluminum with PHF-tau in Alzheimer disease neurofibrillary degeneration evidenced by desferrioxamine-assiated chelating autoclave method[J].Am J Pathol,1999,155:877-885.
[20]Nagata T,Hayatsu M,Kosuge N.Identification of Aluminum Forms In Tea By A1-27NMR[J].Phytochemistry,1992,31:1215-1218.
[21]Rengel Z.Aluminium cycling in the soil-plant-animal-human continuum[J].BioMetals,2004,17:669-689.
[22]Erdemoglu SB,Turkdemir H,Gucer S.Determination of total and fluoride bound aluminium in tea infusions by ion selective electrode and flame atomic absorption spectrometry[J].Anal Lett,2000,33,1513-1529.
[23]Liang Li.The biochemistry and physiology of metallic fluoride:action,mechanism,and implications[J].Crit Rev Oral Med,2003,14:100-113.
[24]Shu WS,Zhang ZQ,Lan CY,et al.Fluoride and aluminium concentrations of tea plants and tea products from Sichuan Province[J].PR China Chemosphere,2003,52:1475-1482.
[25]Lu YI,Guo WF,Yang XQ.Fluoride Content in Tea and Its Relationship with Tea Quality[J].J.Agric.Food Chem,2004,52:4472-4476.
[26]Lung SC,Hsiao PK,Chiang KM.Fluoride concentrations in three types of commercially packed tea drinks in Taiwan[J].Journal of Exposure Analysis and Environmental Epidemilolgy,2003,13:66-73.
[27]孙殿军,刘立志.我国饮茶型氟中毒研究的回顾及展望[J].中国地方病学杂志,2005,24:1-2.
[28]Cao J,Zhao Y,Liu JW.Brick tea consumption as the cause of dental fluorosis among children from Mongol,Kazal and Yugu populations in China[J].Food and Chemical Toxicology,1997,35:827-833.
[29]Michael P,Whyte MD,Kevan MS,et al.Skeletal fluorosis and instant tea[J].Am J Med,2005,118:78-82.
[30]李广生,徐辉.当前氟中毒机制研究中的几个问题[J].中国地方病学杂志,2006,25:119-120.
[31]吕晓红,李广生,孙波.慢性氟中毒大鼠神经细胞凋亡的研究[J].中国地方病学杂志,2000,19:96-98.
[32]Isaacson RL,Varner JA,Jensen KF.Toxin-induced blood vessel inclusions caused by the chronic administration of aluminum and sodium fluoride and their implications for dementia[J].Ann NY Acad Sci.1997,825:152-166.
[33]Varner JA,Jensen KF,Horvath W,et al.Chronic administration of aluminum-fluoride or sodium-fluoride to rats in drinking water:alterations in neuronal and cerebrovascular integrity[J].Brain Res.1998,784:284-298.
[34]Thompson CB.Apoptosis in the pathogenesis and treatment of disease[J].Science,1995,267:1456-1462.
[35]Verma RJ,Trivedi MH,Chinoy NJ.Black tea amelioration of sodium fluoride-induced alterations of DNA,RNA,and protein contents in the cerebral hemisphere,cerebellum,and medulla oblongata regions of mouse brain[J].Fluride,2007,40:7-12.
[36]Sava VM,Yang SM,Hong MY,et al.Isolation and characterization of melanic pigments derived from tea and tea polyphenols[J].Food Chemistry,2001,73:177-184.
[37]Douglas RG,John CR.Mitochondria and apoptosis[J].Science,1998,281:1309.
[38]Yang B,Rchard A.Expression ofbax,bcl-2 and p53 in progressive multifold leukoencephslopathy[J].Mod Pathol,2000,13:1115-1120.
[39]Shibata M,Murray M,Tessler A,et al.Single injections ofa DNA plasmid that contains the human bcl-2 gene prevent loss and atrophy of distinct neuronal populations after spinal cord injury in adult rats[J].Neurorehabil Neural Repair,2000,14:319-330.
[40]Gazzaniga P,Gradilone A,Vercillo R,et al.Bcl-2/Bax mRNA expression ration as prognostic factor in low-grade urinary bladder cancer[J].Ini J Cancer,1996,69:100-102.
[41]Tsujimoto Y,Cossman J,Jaffe E,et al.Involvement of the bcl-2 gene in human follicular lymphoma [J]. Science, 1985, 228(4706):456-461.
[42] Chen J, Graham SH, Nakayama M, et al. Apoptosis repressor genes Bcl-2 and Bcl-x-long are expressed in the rat brain following global ischemia [J]. J Cereb Blood Flow Metab, 1997,17(1):2-10.
[43] Oltvai ZN, Milliman CL, Korsmeger SJ, et al. Bcl-2 heterodimeriaes in vivo with a conserved homloge, bax, that accelerates programmed cell death [J]. Cell, 1993, 74: 609-613.
[44] Lok J, Martin LJ. Rapid subcellular redistribution of Baxprecdes caspase-3 and endonuclear activation during excitoxic neuronal apoptosis in tar brain [J].Neurotrauma, 2002,19(7):815-825.
[45] Yang MS, Wong MH. Changes in Ca, Cu, Fe, Mg, and Zn Contents in Mouse Brain Tissues After Prolonged Oral Ingestion of Brick Tea Liquor Containing a High Level of Al [J]. Hunana Press Inc, 2001, 80:67-76.
[46] Mattson MP, Lovell MA, Ehmann WD, et al. Comparison of the effects of elevated intracellular aluminum and calcium levels on neuronal survival and tau immunore -activity [J]. Brain Res.1993,29:21-31.
[1]Gilman AG.G proteins:transducers of receptor- generated signals[J].Annu Rev Biochem.1987,56:615-649.
[2]Bigay J,Deterre P,Pfister C,et al.Fluoride complexes of aluminium or beryllium act on G-proteins as reversibly bound analogues of the gamma phosphate ofGTP[J].EMBO J.1987,6:2907-2913.
[3]Chabre M.Aluminofluoride and beryllofluoride complexes:new phosphate analogs in enzymology[J].Trends Biochem Sci.1990,15:6-10.
[4]Li L,Fleming N.Aluminum fluoride inhibition of cabbage phospholipase D by a phosphate-mimicking mechanism[J].FEBS Lett 1999,461(1-2):1-5.
[5]Li L,Fleming N.Aluminum fluoride inhibits phospholipase D activation by a GTP-binding protein- independent mechanism[J].FEBS Lett.1999,458(3):419-423.
[6]Rall TW,Sutherland EW,Berthet J.The relationship of epinephrine and glucagon to liver phosphorylase.Ⅳ.Effect of epinephrine and glucagons on the reactivation of phosphorylase in liver homogenates[J].J Biol Chem 1957,224:463-475.
[7]Rail TW,Suthedand EW.Formation of a cyclic adenine ribonucleotide by tissue particles [J].J Biol Chem.1958,232:1065-1076.
[8]Rodbell M,Bimbaumer L,Pohl SL,et al.The glucagon-sensitive adenyl cyclase system in plasma membranes of rat liver.Ⅴ.An obligatory role of guanylnucleotides in glucagon action[J].J Biol Chem.1971,246:1877-1882.
[9]Ross EM,Gilman AG.Resolution of some components of adenylate cyclase necessary for catalytic activity[J].J Biol Chem.1977,252:6966-6969.
[10]Sternweis PC,Gilman AG.Reconstitution of catecholaminesensitive adenylate cyclase.Reconstitution of the uncoupled variant of the $40 lymphoma cell[J].J Biol Chem.1979,254:3333-3340.
[11]Sternweis PC,Gilman AG.Aluminum:a requirement for activation of the regulatory component of adenylate cyclase by fluoride[J].Proc Natl Acad Sci.1982,79:4888-4891.
[12]Fung BK,Hurley JB,Stryer L.Flow of information in the light-triggered cyclic nucleotide cascade of vision[J].Proc NatlAcad Sci.1981,78:152-156.
[13]Sitaramayya A,Virmaux N,Mandel P.On the mechanism of light activation of retinal rod outer segments cyclic GMP phosphodiesterase(light activation-influence of bleached rhodopsin and KF-deinhibition) [J]. Exp Eye Res. 1977,25:163-169.
[14] Stein PJ, Halliday KR, Rasenick MM. Photoreceptor GTP binding protein mediates fluoride activation of phosphodiesterase[J].J Biol Chem. 1985, 260: 9081- 9084.
[15] Kanaho Y, Moss J, Vaughan M . Mechanism of inhibition of transducin GTPase activity by fluoride and aluminum [J]. J Biol Chem. 1985, 260: 11493-11497.
[16] Bigay J, Deterre P, Pfister C, et al. Fluoroaluminates activate transducin-GDP by mimicking the gamma- phosphate of GTP in its binding site [J]. FEBS Lett. 1985,191:181-185.
[17] Goldstein G . Equilibrium distribution of metal-fluoride complexes [J]. Anal Chem. 1964,36:243-244.
[18] Bigay J, Deterre P, Pfister C, et al. Fluoride complexes of aluminium or beryllium act on G-proteins as reversibly bound analogues of the gamma phosphate of GTP [J]. EMBO J.1987, 6:2907-2913.
[19] Higashijima T, Ferguson KM, Sternweis PC, et al. The effect of activating ligands on the intrinsic fluorescence of guanine nucleotide-binding regulatory proteins[J].J Biol Chem. 1987,262:752-756.
[20] Higashijima T, Graziano MP, Suga H, et al. ~(19)F and ~(31)P NMR spectroscopy of G protein alpha subunits. Mechanism of activation by Al~(3+) and F" [J]. J Biol Chem. 1991,266:3396-3401.
[21] Chabre M. Aluminofluoride and beryllofluoride complexes: new phosphate analogs in enzymology [J].Trends Biochem Sci. 1990,15:6-10.
[22] Knowles AR. Enzyme-catalyzed phosphoryl transfer reactions[J]. Annu Rev Biochem. 1980,49:877-919.
[23] Lolis E, Petsko GA. Transition-state analogues in protein crystallography: probes of the structural source of enzyme catalysis [J]. Annu Rev Biochem. 1990,59:597-630.
[24] Thompson PR, Cole PA. Probing the mechanism of enzymatic phosphoryl transfer with a chemical trick [J]. Proc Natl Acad Sci. 2001,98:8170-8171.
[25] Coleman DE, Sprang SR. Reaction dynamics of G-protein catalyzed hydrolysis of GTP as viewed by x-ray crystallographic snapshots of Gial [J]. Meth Enzymol. 1999,308:70-92.
[26] Rodbell M . The complex regulation of receptor- coupled Gproteins [J].Adv Enzyme Regul. 1997, 37:427-435.
[27] Feuerstein J, Goody RS, Webb MR. The mechanism of guanosine nucleotide hydrolysis by p21 c-Ha-Ras. The stereochemical course of the GTPase reaction [J]. J Biol Chem. 1989,264:6188-6190.
[28]Noel JP,Hamm HE,Sigler PB.The 2.2(?) crystal structure of transducin-alpha complexedwith GTPyS[J].Nature.1993,366:654-663.
[29]Coleman DE,Berghuis AM,Lee E,et al.Structures of active conformations of Gial and the mechanism of GTP hydrolysis[J].Science.1994,265:1405-1412.
[30]Kleuss C,Raw AS,Lee E,et al.Mechanism of GTP hydrolysis by G-protein a subunits [J].Proc Natl Acad Sci.1994,91:9828-9831.
[31]Sondek J,Lambright DG,Noel JP,et al.GTPase mechanism of G proteins from the 1.7-(?) crystal structure of transducin a-GDP-AIF_4~-[J].Nature.1994,372:276-279.
[32]Sprang SR.G protein mechanisms:insights from structural analysis[J].Annu Rev Biochem.1997,66:639-678.
[33]Priest ND.The bioavailability and metabolism of aluminium compounds in man[J].Proc Nutr Soc.1993,52:231-240.
[33]WHO/IPCS.Aluminmun[J].environ health critenia 1997.194,1 - 152.
[35]Ringe JD,Rovati LC.Treatment of osteoporosis in men with fluoride alone or in combination with bisphosphonates[J].CalcifTissue Int.2001,69:252-255.
[36]Whitford GM.The physiological and toxicological characteristics of fluoride[J].J Dent Res.1990:539-549;discussion 556-557.
[37]He H,Ganapathy V,Isales CM,et al.PH-dependent fluoride transport in intestinal brush border membrane vesicles[J].Biochim Biophys Acta.1998,1372:244-254.
[38]WHO.Fluorides and Human Health[M].Geneva,1984.
[39]Martin RB.Aluminum:a neurotoxic product of acid rain[J].Accts Chem Res.1994,27:204-210.
[40]Martin RB.Ternary complexes of Al~(3+) and F~- with a second ligand[J].Coord Chem Rev.1996,149:23-32.
[41]Yu P,Phillips BL,Casey WH.Water exchange in fluoroaluminate complexes in aqueous solution:a variable temperature multinuclear NMR study[J].Inorg Chem.2001,40:4750-4754.
[42]Still CN,Kelley P.On the incidence of primary degenerative dementia vs.water fluoride content in South Carolina[J].Neurotoxicology.1980,1:125-131.
[43]Forbes WF,Agwani N.A suggested mechanism for aluminum biotoxicity[J].J Theoret Biol.1994,171:207-214.
[44]Cowburn RF,O'Neill C,Bonkale WL,et al.Receptor-G-protein signalling in Alzheimer's disease[J].Biochem Soc Symp.2001,67:163-175.
[45] Isaacson RL, Vamer JA, Jensen KF. Toxin-induced blood vessel inclusions caused by the chronic administration of aluminum and sodium fluoride and their implications for dementia [J]. Ann NY Acad Sci. 1997, 825:152-166.
[46] Varner JA, Jensen KF, Horvath W, et al. Chronic administration of aluminum-fluoride or sodium-fluoride to rats in drinking water: alterations in neuronal and cerebrovascular integrity [J]. Brain Res. 1998, 784:284-298.
[47] Farley JR, Wergedal JE, Baylink DJ. Fluoride directly stimulates proliferation and alkaline phosphatase activity of boneforming cells [J]. Science. 1983,222: 330-332.
[48] Caverzasio J, Imai T, Ammann P, et al. Aluminum potentiates the effect of fluoride on tyrosine phosphorylation and osteoblast replication in vitro and bone mass in vivo [J]. J Bone Miner Res. 1996,11: 46-55.
[49] Caverzasio J, Palmer G, Suzuki A,et al. Mechanism of the mitogenic effect of fluoride on osteoblast-like cells: evidences for a G protein-dependent tyrosine phosphorylation process [J]. J Bone Miner Res. 1997,12:1975-1983.
[50] Lau KH, Goodwin C, Arias M, et al. Bone cell mitogenic action of fluoroaluminate and aluminum fluoride but not that of sodium fluoride involves up regulation of the insulin-like growth factor system [J]. Bone. 2002, 30:705-711.
[51] Matsuo S, Kiyomiya K, Kurebe M. Mechanism of toxic action of fluoride in dental fluorosis: whether trimeric G proteins participate in the disturbance of intracellular transport of secretory ameloblast exposed to fluoride [J]. Arch Toxicol. 1998, 72:798-806.
[52] Spencer H, Kramer L, Norris C, et al.Osteoporosis: calcium, fluoride, and aluminum interactions [J]. J Am Coll Nutr. 1985,4:121-128.
[53] Nagata T, Hayatsu M, Kosuge N. Aluminium kinetics in the tea plant using ~(27)A1 and ~(19)F NMR [J].Phytochemistry, 1993, 32: 771-775.
[54] Erdemoglu SB, Turkdemir H, Gucer S. Determination of total and fluoride bound aluminium in tea infusions by ion selective electrode and flame atomic absorption spectrometry [J]. Anal Lett. 2000,33,1513-1529.