The effects of fluoride exposure on the functions of reproductive and endocrine systems have attracted widespread attention in academic circle nowadays. However, it is unclear whether the gene-environment interaction may modify the secretion and activity of hypothalamus-pituitary- ovarian (HPO) axis hormones. Thus, the aim of this study was to explore the influence of fluoride exposure and follicle stimulating hormone receptor (FSHR) gene polymorphism on reproductive hormones in Chinese women. A cross sectional study was conducted in seven villages of Henan Province, China during 2010-2011. A total of 679 women aged 18-48 years were recruited through cluster sampling and divided into three groups, i.e. endemic fluorosis group (EFG), defluoridation project group (DFPG), and control group (CG) based on the local fluoride concentration in drinking water. The serum levels of gonadotropin releasing hormone (GnRH), follicle stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2) were determined respectively and the FSHR polymorphism was detected by real time PCR assay. The results provided the preliminary evidence indicating the gene-environment interaction on HPO axis hormones in women.
Adolescent ; Adult ; Age Factors ; Asian Continental Ancestry Group ; China ; Cross-Sectional Studies ; Estradiol ; blood ; Female ; Fluoridation ; adverse effects ; Fluorides ; administration & dosage ; adverse effects ; urine ; Follicle Stimulating Hormone ; blood ; Gene-Environment Interaction ; Gonadotropin-Releasing Hormone ; blood ; Humans ; Hypothalamus ; physiology ; Luteinizing Hormone ; blood ; Middle Aged ; Ovary ; physiology ; Pituitary Gland ; physiology ; Polymorphism, Single Nucleotide ; Receptors, FSH ; genetics ; Tobacco Smoke Pollution ; Young Adult

Animals ; Bone and Bones ; drug effects ; Copper ; pharmacology ; therapeutic use ; Fluoride Poisoning ; prevention & control ; Fluorides ; blood ; toxicity ; urine ; Lipid Metabolism ; drug effects ; Molybdenum ; toxicity ; Rabbits ; Trace Elements ; pharmacology ; therapeutic use

OBJECTIVETo explore the influence of water fluoride exposure on reproductive hormones in female.

METHODSCross-sectional study was conducted in seven villages of a county in Henan province by using simple random sampling including high fluoride area, defluoridation project area and control area on April, 2011 based on the preliminary study results of fluoride concentration in drinking water. Women who were born and growth or lived in the village at least 5 years and aged 18-48 years old were recruited using cluster sampling. They were divided into high fluoride group (HFG, 116 subjects), defluoridation project group (DFPG, 132 subjects) and control group (CG, 227 subjects) in accordance with the above areas. All subjects accepted questionnaire and physical checkup. Fasting blood and morning urine samples were collected. The concentration of fluoride in urine was determined by fluoride ion selective electrode method. The serum level of GnRH was detected using enzyme linked immunosorbent assay (ELISA). The serum level of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T), estradiol (E2) were determined by chemiluminesence immunoassay (CLIA).

RESULTSThe average age was (39.44 ± 7.34), (38.84 ± 8.03), (37.45 ± 7.70) years old in female from DFPG, HFG and CG respectively, there were no significant differences among the three groups (F = 3.02, P = 0.05). The urine fluoride levels were (1.34 ± 1.07), (2.59 ± 1.57), (0.92 ± 0.46) mg/ml in female from DFPG, HFG and CG respectively, there was a significant difference among three groups (F = 105.38, P < 0.01). No significant differences were observed of serum GnRH, LH, T, FSH and E2 among three groups in follicular phase (P > 0.05). The serum levels of E2 in Ovulatory period were 67.73, 58.09, 84.96 pg/ml in female from DFPG, HFG and CG respectively. It was lower in HFG than that in CG (H = 4.00, P < 0.05). The serum levels of T in Ovulatory period were 0.55, 0.45, 0.55 ng/ml in female from DFPG, HFG and CG respectively. It was lower in HFG than that in DFPG (H = 6.47, P < 0.05), but no significant difference was observed between HFG and CG (H = 2.41, P > 0.05). The serum levels of GnRH in Luteal phase were 24.09, 20.16, 23.50 ng/ml in female from DFPG, HFG and CG respectively. It was lower in HFG than that in DFPG (H = 14.14, P < 0.05) and CG (H = 12.53, P < 0.05). The serum level of E2 in luteal phase were 81.47, 64.60, 74.55 pg/ml in female from DFPG, HFG and CG respectively. It was lower in HFG than that in DFPG (H = 5.69, P < 0.05). As for LH, FSH and T, no significant differences were observed among the three groups (P > 0.05 respectively). The abnormal rates of E2 level were 22.73 (30/102), 37.93 (44/72), 20.26 (46/181) in female from DFPG, HFG and CG respectively. The E2 abnormal rate in female from HFG was higher that from DFPG (χ(2) = 6.82, P < 0.05) and CG (χ(2) = 12.38, P < 0.05).

CONCLUSIONFluoride exposure may influence reproductive hormones in female, especially in ovulatory and luteal phase of menstrual cycle.

Adult ; Cross-Sectional Studies ; Drinking Water ; chemistry ; Environmental Exposure ; adverse effects ; Estradiol ; blood ; Female ; Fluorides ; adverse effects ; urine ; Follicle Stimulating Hormone ; blood ; Gonadotropin-Releasing Hormone ; blood ; Humans ; Luteinizing Hormone ; blood ; Menstrual Cycle ; drug effects ; Middle Aged ; Progesterone ; blood ; Testosterone ; blood

OBJECTIVETo study the effect of fluoride on the oxidative stress of the rats in endemic fluorosis of coal burning and Mn-SOD expression at mRNA and protein levels.

METHODSSD rats were divided into 2 groups (the number of female and male in each group was the same): control group and fluorosis group. All rats of the fluorosis group were fed corn dried by burning coal from endemic fluorosis areas with high fluoride content (fluoride 17 mg/kg in feed) to establish an animal model of fluorosis. In these rats, dental fluorosis was evaluated. The fluoride content in the urine was measured by fluorine ion-elective electrode method. The hepatic tissue and serum level of malonaldehyde (MDA) and the activities of superoxide dismutase (SOD) and glutathion reductase (GR) were measured by biochemical methods. The index signs of liver function were also measured from the serum. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were performed to detect the alterations of Mn-SOD expression in the liver at mRNA and protein levels.

RESULTSThe dental fluorosis was observed in the fluorosis group, and the incidence was 11/11. The fluoride contents [(3.50 ± 2.58) mg/L] in the urine of fluorosis rats were increased as compared with the control [(1.42 ± 0.38) mg/L] (P < 0.05). AST [(223.74 ± 71.51) U/L] and total protein [(72.43 ± 5.59) g/L] of the hepatic function index in fluorosis rats showed obviously abnormal as compared with the control [(169.28 ± 53.74) U/L and (82.36 ± 7.31) g/L], respectively (P < 0.05). In the liver the content of MDA [(10.41 ± 0.59) µmol/g protein] increased as compared to the control [(5.80 ± 1.31) µmol/g protein, P < 0.01], and the activities of SOD [(62.60 ± 8.65) U/mg protein] and GR [ (1.17 ± 0.66) U/g protein] markedly decreased in the fluorosis group compared to the control [SOD (117.28 ± 8.64) U/mg protein and GR [(8.80 ± 1.59) U/g protein; P < 0.05, P < 0.01]. The level of Mn-SOD in the liver was markedly decreased in the fluorosis group [(14.83 ± 2.50) U/mg protein] as compared with the control [(34.05 ± 5.22) U/mg protein, P < 0.01]. The levels of mRNA (0.64 ± 0.15) and protein (0.84 ± 0.13) of Mn-SOD were markedly decreased in the fluorosis group as compared with the control [(0.86 ± 0.21) and (1.04 ± 0.14)], respectively (P < 0.05, P < 0.01).

CONCLUSIONSFluorosis can decrease the activities of Mn-SOD, which is associated with decreased levels of mRNA and protein of Mn-SOD. Down-regulation of Mn-SOD expression may play an important role in the aggravation of oxidative stress in endemic fluorosis.

Animals ; Coal ; Down-Regulation ; Female ; Fluorides ; urine ; Fluorosis, Dental ; metabolism ; Glutathione Reductase ; blood ; metabolism ; Liver ; metabolism ; Liver Function Tests ; Male ; Malondialdehyde ; blood ; metabolism ; Oxidative Stress ; RNA, Messenger ; metabolism ; Rats ; Rats, Sprague-Dawley ; Superoxide Dismutase ; blood ; genetics ; metabolism

OBJECTIVETo investigate the expressions of mRNA and protein of p38, Osx, PI3K, Akt1 in the rats bone with chronic fluorosis.

METHODSDental fluorosis were observed and the fluoride contents in the urine and bone were detected by fluorin-ion selective electrode. The morphologic changes and ultrastructure of rats' bone were observed by light and electronic microscopy. The expressions of protein and mRNA of p38, Osx, PI3K and Akt1 were detected by immunohistochemistry and real-time PCR, respectively. The contents of BALP and BGP in serum were detected by ELISA.

RESULTSThe rates of dental fluorosis in the fluorosis rats were increased, and the fluoride contents in bone and urine of the fluorosis rats were increased compared to the control group, the difference was statistically significant (P < 0.05). The bone trabeculae thickness and density and the thickness of bone cortex in fluorosis rats were remarkably increased, the space of bone trabeculae was reduced, and in accordance with the matching morphometrical indices, the difference was statistically significant (P < 0.05) as compared with the control rats. The contents of BALP [(54.61 ± 2.27) U/L] and BGP [(2.38 ± 0.16) µg/L]in the fluoride groups were higher than those in the control group, the difference was statistically significant (P < 0.05). Ultrastructurally, the broadening of the osseouslacuna was observed. The reduced protuberances of the osteocytes, the unclear organelle structure, pyknosis, karyotheca increasation and edged chromatin were also observed. Compared to the control group, the expressions of protein and its mRNA of p38, Osx, PI3K and Akt1 were higher in the fluorosis rats than those in the control rats, and the difference was statistically significant (P < 0.05). There is no any expression of p38, Osx, PI3K and Akt1 in the osteocytes in fluorosis rats.

CONCLUSIONSThe over-expression of p38, Osx, PI3K and Akt1 in bone tissue of fluorosis rats may relate to the accumulation of fluorine in the body. The bone injury mainly occur in the stage of the differentiation and proliferation. The upregulation of P38MARK signal path and PI3K/Akt1 signal path may be involved in the pathogenesis of bone injury caused by fluoride.

Alkaline Phosphatase ; blood ; Animals ; Bone and Bones ; metabolism ; pathology ; ultrastructure ; Fluoride Poisoning ; metabolism ; pathology ; Fluorides ; metabolism ; urine ; Fluorosis, Dental ; metabolism ; pathology ; Immunohistochemistry ; Microscopy, Electron, Transmission ; Osteocalcin ; blood ; Phosphatidylinositol 3-Kinases ; genetics ; metabolism ; Proto-Oncogene Proteins c-akt ; genetics ; metabolism ; RNA, Messenger ; metabolism ; Rats ; Rats, Sprague-Dawley ; Real-Time Polymerase Chain Reaction ; Signal Transduction ; Sodium Fluoride ; toxicity ; Transcription Factors ; genetics ; metabolism ; p38 Mitogen-Activated Protein Kinases ; genetics ; metabolism

OBJECTIVETo investigate the changes of mRNA and protein expression of CaN in the bone of rats with chronic fluorosis, and the mechanism of skeletal fluorosis.

METHODSThirty-six SD rats were divided into three groups (12 in each group, half male and half female selected according to body weight): control, low-dose and high-dose fluorosis groups. Controls were fed tap water (NaF < 0.5 mg/L), experimental animals in the low- or high-dose groups were fed water containing NaF of 5.0 and 50.0 mg/L, respectively. The rats were sacrificed after 6 months of treatment with fluoride. The serum was kept for testing bone metabolic marker bone gla protein (BGP) by enzyme-linked immunosorbent assay (ELISA), the protein and mRNA levels of CaN in distal femur of the rats with chronic flurosis were assessed by immunohistochemistry and in-situ hybridization.

RESULTSThe levels of BGP (1.99 ± 0.62, 2.38 ± 0.16)µg/L in the low- or high-dose fluorosis groups were higher than that in the control group (0.15 ± 0.03) µg/L; and the high fluorosis group showed higher level than the low fluorosis group (all P < 0.05). Compared to the control group (131.11 ± 1.95, 111.82 ± 2.39), the protein and mRNA levels of CaN were higher in the low- or high-dose fluorosis groups (142.69 ± 1.17, 157.54 ± 1.88 and 121.28 ± 3.27, 134.63 ± 3.19, respectively), and the high fluorosis group showed higher levels than the low fluorosis group (all P < 0.05).

CONCLUSIONSBGP content could be used as a bone metabolic index in endemic fluorosis disease. Fluoride might up-regulate the mRNA and protein expression of CaN, and the changes in CaN level may be involved in the increase of the bone turnover and could be one of the pathogenetic factors in fluorosis.

Animals ; Bone and Bones ; metabolism ; Calcineurin ; genetics ; metabolism ; Female ; Fluoride Poisoning ; metabolism ; pathology ; Fluorides ; metabolism ; urine ; Fluorosis, Dental ; metabolism ; pathology ; Male ; Osteoblasts ; metabolism ; Osteocalcin ; blood ; RNA, Messenger ; metabolism ; Rats ; Rats, Sprague-Dawley ; Sodium Fluoride ; poisoning

BACKGROUNDHigh fluoride exposure can result in dental fluorosis. Fluoride and iodine are coexistent in the drinking water of areas in China and may affect the prevalence of dental fluorosis and osteogenesis. The aim of this study was to investigate the relationship between serum calciotropic hormone level, and dental fluorisis in children exposed to different concentrations of fluoride and iodine in drinking water.

METHODSA pilot study was conducted in three villages located in the Kaifeng and Tongxu counties of Henan Province, China in 2006. Children aged 8 to 12 years, born and raised in the three villages were recruited. The fluoride levels in the samples of urine from these children were detected by fluoride ion selective electrode. Calcitonin and osteocalcin levels in the serum, and serum calcium were measured by radioimmunassay and flame atomic absorption spectrometry, respectively.

RESULTSFluoride levels in urine were significantly lower in children from control area (CA) as compared with those from the high fluoride & iodine areas (HFIA) and the high fluoride area (HFA) (P < 0.05 respectively), and no statistically significant difference was found between the children from HFIA and HFA. Additionally, calcitonin levels in the serum were significantly lower in children from CA and HFA as compared with that from HFIA (P < 0.05 respectively), and osteocalcin levels in the serum was lower in children from CA than those from HFIA (P < 0.05). No statistically significant difference in serum osteocalcin concentrations was found between children from HFA and HFIA.

CONCLUSIONThis study provides an evidence that iodine exposure may modify the serum calciotropic hormone levels related to fluorine exposure.

Calcitonin ; blood ; Child ; Female ; Fluorides ; administration & dosage ; Fluorosis, Dental ; epidemiology ; Humans ; Iodine ; administration & dosage ; Male ; Osteocalcin ; blood ; Pilot Projects ; Prevalence ; Water Supply ; analysis

OBJECTIVEBy using Benchmark Dose (BMD) approach to explore the relations among drinking water fluoride, urine fluoride, serum fluoride and dental fluorosis; and to evaluate the significance of urine fluoride and serum fluoride in control and prevention of endemic fluorosis.

METHODS512 children (290 in Xinhuai Village, 222 in Wamiao Village) aged 8-13 years were recruited in the study. Epidemiological methods were used to investigate the prevalence of dental fluorosis, and the levels of urine fluoride, serum fluoride, and drinking water fluoride in superficial well. The children were divided into six subgroups by the concentration of fluoride in drinking water: < 0.5 mg/L, 0.5-mg/L, 1.0-mg/L, 2.0-mg/L, 3.0-mg/L and > or = 4.0 mg/L.

RESULTSThere was significant dose-response relationship between the drinking water fluoride and the prevalence of dental fluorosis or the prevalence of defect dental fluorosis. The BMDLs (Benchmark Dose Lower Bound) were 1.01 and 1.30 mg/L, respectively. Urine fluoride and serum fluoride also had significant dose-response relationship to the prevalence of dental fluorosis or defect dental fluorosis. The correlation coefficient between drinking water fluoride and urine fluoride was 0.717, and it was 0.855 between drinking water fluoride and serum fluoride, and 0.617 between urine fluoride and serum fluoride.

CONCLUSIONSThe currently national standard of fluoride in drinking water in China is safe and reasonable. As a biological monitoring index, the levels of fluoride in serum may be more useful than that in urine in the control and prevention of endemic fluorosis.

Adolescent ; Child ; China ; epidemiology ; Environmental Monitoring ; Epidemiological Monitoring ; Female ; Fluorides ; analysis ; blood ; urine ; Fluorosis, Dental ; epidemiology ; Humans ; Male ; Prevalence ; Water Supply ; analysis ; standards

OBJECTIVETo study the accumulation of fluoride in rat hippocampus and its effect on cholinesterase activity.

METHODSRats were subchronically exposed to NaF, and fluoride concentration and cholinesterase activity in rat hippocampus were determined.

RESULTSFluoride concentration in rat hippocampus was significantly correlated with the dosage of fluoride, and there were significant differences among high dosage group [(13.03 +/- 1.79) micro g/g], low dosage group [(9.83 +/- 0.92) micro g/g] and control [(8.27 +/- 1.11) micro g/g], P < 0.01. Acetylcholinesterase activities among three groups [(0.111 +/- 0.031) micro mol/mg, (0.143 +/- 0.025) micro mol/mg, (0.183 +/- 0.027) micro mol/mg] were also significantly different (P < 0.01), which was negatively correlated with fluoride concentration in rat hippocampus (r = -0.700, P < 0.01). The activity of butylcholinesterase in high dosage group [(0.041 +/- 0.010) micro mol/mg] was different from that of control [(0.067 +/- 0.025) micro mol/mg, P < 0.05], but the activity was not significantly related with fluoride concentration in rat hippocampus (r = -0.317, P = 0.094).

CONCLUSIONFluoride may go through the blood-brain barrier and accumulate in rat hippocampus, and inhibit the activity of cholinesterase.

Acetylcholinesterase ; metabolism ; Animals ; Blood-Brain Barrier ; Butyrylcholinesterase ; metabolism ; Fluoride Poisoning ; metabolism ; Fluorides ; pharmacokinetics ; Hippocampus ; metabolism ; Male ; Organ Size ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To characterize Stat activity in synovial tissue in rheumatoid arthritis (RA) in order to see if Stat molecule contributes to the pathogenesis of RA by regulatory expression of genes that play an important role in inflammation and tissue destruction. METHODS: Synovial tissue were obtained immediately after operative excision. Immuno-histochemistry was done with the antibodies for Stat 3 and Stat 5. Cells were stimulated with interleukin 6 (IL-6) and soluble interleukin 6 receptor (sIL-6R) or steroid using chambered slide. In supershift experiment, cell extracts were incubated with 0.5ng of 32P-labelled double-stranded oligonucleotide probe. Samples were resolved on 4.5% polyacrylamide gels, which was transferred to polyvinylidene fluoride membranes. Anti-phosphotyrosine Stat 3 antibody was used for Western blotting. RESULTS: Stat 3 was not shown on the synovial tissue section done by immuno-histochemistry. However, activated Stat 3 was expressed on cultured synovial cell stimulated with IL-6 and sIL-6R, and also with IL-6 and dexamethasone using chambered slide. In contrast to Stat 3, activated Stat 5 was expressed on the synovial tissue section, especially around blood vessel. CONCLUSION: Stat is activated in cultured synovial cells as shown in other immune associated cells, and IL-6 is the strong activator of Stat 3. Further analysis of the regulation of Stats in synovitis and the role of Stats in driving synovial inflammation will yield insight into the pathogenesis of RA and the development of novel therapeutic modality.
Antibodies ; Arthritis, Rheumatoid* ; Blood Vessels ; Blotting, Western ; Cell Extracts ; Dexamethasone ; Fluorides ; Gels ; Inflammation ; Interleukin-6 ; Membranes ; Receptors, Interleukin-6 ; Signal Transduction ; Synovitis