| ObjectiveDental fluorosis is one of the most serious damages of endemic fluorosis thatinfluences tooth development of children. Many discoveries suggested that not everychild lived in endemic fluorosis area suffered from dental fluorosis. The aim of thisstudy was to expolre the relationship of estrogen receptor α (ERα) rs3798577polymorphism, the methylatioan level of ERα gene promoter and children dentalfluorosis, as well as to provide the genetic and epigenetic evidences of the occurrenceand development of dental fluorosis.Subjects and methods1. Recruitment of subjects:8-12years old children born and growth in Kaifeng andTongxu counties were selected with cluster samplingAll subjects were divided intotwo groups, endemic group (average water fluoride was2.44mg/L) and control group(average water fluoride was0.37mg/L) according to whether locate drinking waterfluoride exceeds1.0mg/L or not. And the endemic group could be divided intocontrol from endemic group, cases from endemic group, then all subjects weredivided into three groups (cases from endemic group, controls from endemic groupand controls), there were285children in this study.2. Dental fluorosis was identified with dean’s method by public health practitionersand dental practitioners.3. Using flame atomic absorption spectrometry to measure serum calcium levelsand fluoride ion selective electrode to measure urine fluoride.4. ERα gene rs3798577genotypes were identified with Taqman probe method andwere detected by real-time PCR instrument.5. The methylation level of ERα promoter was detected by real-time PCRinstrument.6. Data was analysed by SPSS12.0, main methods which used in this paper were ttest, ANOVA, chi-square test, logistic regression and so on. P<0.05was considered significant.Results1. The water fluoride concentration in endemic group was significantly higer thanthat in control group (t=-4.379, P<0.05). there were no significant differences offluoride concentration in vegetables, crops and plow pan layer of soil betweenendemic group and control group (P﹥0.05respectively), but the water-solublefluorine and total fluorine in plough layer were higher in endemic group than those incontrol group (P<0.05).2. The distribution of children whose urine fluoride exceeded1.5mg/L in endemicgroup (71.0%) was significantly different from control group (11.5%)(P<0.05). Theurine levels of children in endemic group were significant higher than those ofchildren in control group (F=52.117, P<0.001). But the serum levels of children haveopposite conclusion (F=8.503, P<0.001).3. There were no significant differences of ERα gene rs3798577genotypesdistribution among different groups, different gender and different urine fluoridelevels (P﹥0.05respectively). But it is found that serum calcium levels of childrenwith the same ERα gene rs3798577genotype in endemic group were significantlylower than those in control group (P<0.05).4. Although there were no significant differences of methylation levels in ERαpromoter of children among different groups, different dental fluorosis severity anddifferent urine fluoride levels. It is found that children with higher dental fluorosisseverity have higher methylation levels in ERα promoter. There was a negativerelationship between methylation level in ERα promoter and serum calcium level ofchildren（r=-0.162，P=0.034）.Conclusion1. There was no relationship between children dental fluorosis and ERα rs3798577polymorphism.2. It was high fluoride exposure but not ERα rs3798577polymorphism orMethylation level of ERα promoter that may affect serum Calcium level.3. Methylation of ERα promoter may influence calcium metabolism firstly, thenplay a role in the development of dental fluorosis. 4. There were no significant differences between dental fluorosis and the interactionof ERα rs3798577polymorphism and Methylation level of ERα promoter... |
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