ABSTRACT
ObjectiveTo observe the changes of fluoride content in serum,bone and urine after rats were exposed to single fluoride,single aluminum or fluoride combined with aluminum and to investigate the effects of different doses of aluminum on fluoride accumulation and excretion in rats.Methods Male Wistar rats were randomly divided into 9 groups based on 3 × 3 factorial design.Different doses of fluoride(NaF,0,50,200 mg/L)and(or) aluminum(AlCl3,0,100,200 mg/L) were administered to rats in each group by drinking water.The rats took food and water ad libitum during the experimental period.After feeding for 18 weeks,rats with obvious dental fluorosis were determined as successful establishment of animal model.The fluoride content in the serum,bones and urine were measured.Results Fluoride affected the fluoride content in serum,bones and urine(F=166.74,577.81,160.96,all P ＜ 0.01 ).The interaction of fluoride and aluminum on serum,bone and urinary fluoride were statistically significant (F =7.95,5.13,6.94,all P ＜ 0.01 ).When the fluoride level was 50 mg/L,the serum fluoride contents were [ (0.08 ± 0.03) and (0.08 ± 0.02) mg/L] in the aluminum levels of 0 and 100 mg/L groups,which was higher than that of the aluminum level of 200 mg/L group[ (0.04 ± 0.01)mg/L,F=7.14,5.78.all P＜ 0.05].The bone fluoride content in the 0 mg/L aluminum level group[ (1996.53 ± 383.73) mg/kg] was higher than that of the 100 and 200 mg/L groups[(1252.51 ± 189.08),( 1160.63 ± 129.63) mg/kg,F=20.54,24.56,all P ＜ 0.01 ].When the fluoride level was 200 mg/L,the bone fluoride contents were decreased with the increasing doses of aluminum[ (4668.70 ± 887.67),(3920.30 ± 528.31 ),(3297.64 ± 396.04) mg/kg].Between any two groups,the differences were statistically significant (F =15.59,52.31,14.38,all P ＜ 0.01 ).When the fluoride level was 50 mg/L,the urinary fluoride content in the 0 mg/L aluminum level group[ (34.054 ± 9.30)mg/L] was higher than that of the 100,200 mg/L groups[( 14.81 ± 6.32),(14.67 ± 3.42) mg/L,F =25.30,24.32,all P ＜ 0.01 ].When the fluoride level was 200 mg/L,the urinary fluoride contents in the 0,100 mg/L aluminum level groups[ (57.14 ± 21.38),(51.75 ± 8.39)mg/L] were higher than that of the 200 mg/L group[(34.839 ± 9.30) mg/L,F=30.04,20.31,all P ＜ 0.01 ].ConclusionsAluminum is an antagonist of fluoride.The antagonism could be enhanced as the dose of aluminum increased.In this study,aluminum could effectively counteract the absorption of fluoride in rat model when the ratio of fluoride to aluminum is 1 ∶ 2.
ABSTRACT
Objectives To screen the differentially expressed proteins in serum of population chronically exposed to arsenic in drinking water,thus to provide candidate protein biomarkers for arsenic exposure and arsenicosis.Methods Subjects were selected from the drinking water type of endemic arsenicosis areas in Shanxi province,China.Demographic characteristics,history of arsenic exposure,cigarette smoking,alcohol drinking,health and other information were collected using questionnaire.The subjects were divided into low-arsenic group (with arsenic in drinking water ＜ 10 μg/L),medium-arsenic group( 10 - 50 μg/L),high-arsenic group( ＞ 50 μg/L),and arsenicosis group(the drinking water with arsenic ＞ 50 μg/L was replaced by low arsenic water ＜ 10 μg/L).The number of cases in each group was 30.The arsenicosis patients were diagnosed according to “Standard of Diagnosis for Endemic Arsenism” (WS/T 211-2001 ).With the principle of informed consent,blood samples were collected.Differentially expressed serum proteins of different arsenic exposure groups and arsenicosis group were screened by two-dimensional differential gel electrophoresis(2-D DIGE),and further identified by mass spectrometry (MS).Results An average of (1299 ± 167) protein spots were identified in 6 gel images and 688 protein spots were discovered repeatedly in at least 5 gels.There were 33 protein spots differentially expressed among low-,medium- and high-arsenic groups P ＜ 0.01).Fifty four protein spots were significantly different among low-,medium-,high-arsenic exposure groups and arsenicosis group(P ＜ 0.01 ).Twenty five protein spots were selected for MS analysis,and13 protein spots were identified.Compared with low-arsenic group,the expressions of apolipoprotein A-Ⅳ,retinol binding protein,and estrogen receptor hypothalamic isoform in medium- and higharsenic exposure groups were down regulated,and the expressions of component 4A and 4B were up regulated.Compared with low-,medium- and high-arsenic groups,the expressions of beta-2-glycoprotein Ⅰ,Keratin 1,hemopexin,complement C1r subcomponent,and ficolin-3 in arsenicosis group were down regulated,and the expressions of pigment epithelial-differentiating factor,alpha-1-microglobulin and carboxypeptidase N catalytic chain were up regulated.Conclusions Chronic arsenic exposure can significantly change population's serum protein expression.Differentially expressed proteins in arsenicosis patients will not decline with the decline of arsenic in a short term.Whether or not the differentially expressed proteins identified in this study can be used as biomarkers for arsenic exposure and arsenicosis needs to be further verified.