Objective To investigate the effects of mTOR/S6K1 signaling pathway on the development of insulin resistantce. Methods 20 male C57BL/6 mice were divided into normal diet group (NC) and high fat diet group (HF).HF mice were fed with high fat diet for 14 weeks and insulin resistance was confirmed in all mice. We observed the morphology of pancreatic islet by HE staining. Serum insulin concentration was also evaluated by ELISA. Northern blot, Western blot and immunofluorescence were performed to detect mTOR and S6K1 mRNA and protein expression in skeletal muscle. Results As compared with NC group,HF group showed that the body weight and fasting serum insulin level were increased by 21.99%(P＜0.05) and 181.82%(P＜0.01) respectively;the area of pancreatic islet was significantly increased;glucose tolerance was impaired;expressions of mTOR mRNA (125.61±10.43 vs 100.00, P＜0.05) and protein (137.41±7.86 vs 100.00, P＜0.01) were significantly increased. And we also found an significant increase in total S6K1 mRNA (154.98±16.26 vs 100.00, P＜0.01) and protein (137.36±3.08 vs 100.00,P＜0.01) as well as pS6K1 protein (390.15±69.62 vs 50.59±16.65,P＜0.01)expression in HF group as compared with NC group.Conclusions mTOR/S6K1 signaling pathway plays an important role in the development of higt fat diet induced insulin resistance.

Objective To explore the effects of different doses of sodium fluoride (NaF) on cartilage lesion and expression of interleukin-6 (IL-6) in serum and cartilage tissue of Balb/c mice.Methods Sixty-four 5-week-old male Balb/c mice were divided into 4 groups based on body weight via the random number table method and 16 mice were in each group.The mice in control group were fed with distilled water,and experimental animals in low,middle and high fluoride groups were fed with distilled water containing NaF 25,50 and 100 mg/L,respectively.The mice were weighed once a week and fed for three months to establish the drinking water fluorosis model.The fluoride contents in spine were detected via the fluorin-ion selective electrode method.The pathological changes in articular cartilage and epiphyseal plate cartilage were observed through optical microscope.The levels of serum IL-6 and souble IL-6 receptor (sIL-6R) were detected via the enzyme-linked immunosorbent assay.The expression of IL-6 protein in articular cartilage and epiphyseal plate cartilage was examined by immunohistochemistry.Results From the sixth week of the experiment,compared with other 3 groups,the body weight of high fluoride group decreased significantly (all P ＜ 0.05);from the seventh week,compared with control and low fluoride groups,the body weight of middle fluoride group decreased significantly (all P ＜ 0.05);throughout the experiment,compared with control group,the body weight of low fluoride group had not changed significantly (all P ＞ 0.05).The fluoride contents of bone in control group,low fluoride group,middle fluoride group and high fluoride group were (842.46 ± 89.27),(1 705.05 ± 105.76),(2 614.17 ± 156.10) and (3 444.58 ± 233.69) mg/kg,respectively.The differences between groups were statistically significant (F =309.716,P ＜ 0.05),and fluoride contents of bone increased with increase of fluoride doses (all P ＜ 0.05).Under optical microscope,the cartilage tissue of control group was normal,while articular cartilage and epiphyseal plate cartilage showed different degrees of cartilage ossification in fluorosis mice and the changes increased with the increase of fluoride doses.The levels of serum IL-6 in control group,low fluoride group,middle fluoride group and high fluoride group were (5.98 ± 1.43),(7.54 ± 2.16),(5.25 ± 1.97) and (6.31 ±-1.36) ng/L,respectively.The differences between groups were statistically significant (F =3.840,P ＜ 0.05),low fluoride group was significantly higher than control group (P ＜ 0.05),and middle fluoride group was significantly lower than low fluoride group (P ＜ 0.05).The levels of serum slL-6R in control group,low fluoride group,middle fluoride group and high fluoride group were (0.83 ± 0.20),(0.93 ± 0.23),(0.82 ±0.27) and (0.92 ± 0.28) μg/L,respectively.The differences between groups were not statistically significant (F =0.738,P ＞ 0.05).Immunohistochemical results showed that articular cartilage full-layer cells in each group expressed IL-6 protein especially in the middle layer of chondrocytes,while IL-6 protein only expressed in hypertrophic chondrocytes of epiphyseal plate cartilage.Comparing with other groups,IL-6 positive cells were the most and had the deepest staining in low fluoride group.Conclusions Different doses of NaF could not only cause cartilage lesion,but also change the expression of IL-6 in serum and cartilage tissue of Balb/c mice.The results indicate that IL-6 may be involved in the cartilage lesion caused by fluoride.

Objective:Through determination of urinary arsenic metabolites in high water arsenic exposed areas of Jilin and Shanxi provinces, to explore the mode and possible influencing factors of arsenic metabolism in different populations.Methods:From October 2018 to August 2019, a cluster sampling was carried out in villages (arsenic in drinking water ≥0.05 mg/L) of some townships (towns) in Lyuliang City, Shanxi Province and Baicheng City, Jilin Province for epidemiological investigation and general health examination. The residents over 35 years old drinking water from local centralized water supply and small well water sources were selected as arsenic exposure group, and people (nearby low-arsenic water source areas) with the same diet and living habits and similar economic conditions were selected as control group. Urine samples were collected. Liquid chromatography-atomic fluorescence spectrometry(LC-AFS) technology was used to separate and detect 4 species of arsenic compounds, including trivalent inorganic arsenic (iAs Ⅲ), pentavalent inorganic arsenic (iAs Ⅴ), methylated arsine (MMA), and dimethylated arsine (DMA). Total arsenic (tAs), inorganic arsenic percentage (iAs%), MMA percentage (MMA%), DMA percentage (DMA%), primary methylation index (PMI) and the secondary methylation index (SMI) were calculated. The influencing factors of arsenic metabolism were analyzed by multiple linear regression. Results:A total of 1 415 villagers were investigated, including 1 256 in arsenic exposure group and 159 in control group. Compared with the control group, there were no significant differences in age, gender ratio and occupation distribution between arsenic exposure group and control group ( P > 0.05), but there were significant differences in smoking, drinking, body mass index (BMI) and education level distribution ( P < 0.05). The median of urinary tAs, iAs%, MMA%, DMA%, PMI and SMI in control group and arsenic exposure group were 12.86 μg/L, 15.03, 5.23, 76.35, 84.97, 93.68 and 69.68 μg/L, 10.24, 8.37, 79.31, 89.76, 90.65, respectively, the levels of urinary tAs, DMA% and PMI in arsenic exposed group were higher than those in control group, while iAs% and SMI were lower than those in control group, the differences were statistically significant ( U=- 13.87, - 4.30, - 6.64, - 6.64, - 1.99, P < 0.05). After analysis of the factors influencing urinary arsenic metabolism in the population, we found that age and BMI had an impact on iAs% ( β=- 0.08, - 0.08, P < 0.05); gender, drinking, BMI and education level were influencing factors of MMA% ( β =- 0.11, - 0.09, - 0.07, 0.08, P < 0.05); DMA% was mainly affected by age, gender, BMI and education level ( β = 0.06, 0.09, 0.10, - 0.09, P < 0.05); PMI was mainly affected by age and BMI ( β = 0.08, 0.08, P < 0.05); while SMI was affected by gender, drinking, BMI and education level ( β=0.09, 0.08, 0.08, - 0.09, P < 0.05). Conclusions:The urinary arsenic metabolism models of different arsenic exposed groups are different. Age, gender, smoking, drinking, BMI and education level may be influencing factors of different arsenic metabolism models.

Objective To detect the modification levels of H2AKll9 ubiquitination (H2AK119ub) and H2BK120ub,and to analyze the relationship between the levels of H2AK119ub,H2BK120ub and arsenic exposure.Methods A cross-sectional study was conducted in typical areas of drinking water type of endemic arsenicosis in Shanxi and Jilin provinces.Totally 281 residents who had drank local water for more 10 years were enrolled in this study,these participants were divided into control group (water arsenic content ＜ 0.01 mg/L),low arsenic exposure group (water arsenic content ranged 0.01-0.05 mg/L),medium arsenic exposure group (water arsenic content ranged ＞ 0.05-0.10 mg/L) and high arsenic exposure group (water arsenic content ＞ 0.10 mg/L).Among them,including 60 subjects in control group (20 males and 40 females),61 subjects in low arsenic exposure group (27 males and 34 females),50 subjects in medium arsenic exposure group (17 males and 33 females),and 110 subjects in high arsenic exposure group (40 males and 70 females).Drinking water and urine samples were collected and the arsenic content was detected by the method of atomic fluorescence spectrometry.After extracting leukocytes histone from the peripheral venous blood that collected from the subjects,the levels of H2AK119ub and H2BK120ub were detected by dot blotting.The levels of water arsenic,urinary arsenic,water arsenic accumulative intake,H2AK119ub and H2BK120ub were expressed as medium and quartile [M (P25,P75)].Results Age,body mass index (BMI),gender,smoking and alcohol drinking between control group and water arsenic exposure groups had no statistical differences (x2 =3.780,3.572,1.938,4.937,6.025,all P ＞ 0.05).Compared the contents of water arsenic [0.005 (0.003,0.006),0.024 (0.017,0.037),0.076 (0.057,0.084),0.150 (0.124,0.185) mg/L],the contents of urinary arsenic [0.011 (0.006,0.017),0.018 (0.004,0.072),0.061 (0.032,0.124),0.134 (0.069,0.223) mg/L],the water arsenic accumulative intake [0.342 (0.248,0.477),1.641 (1.012,2.324),5.273 (3.690,7.036),7.716 (5.608,12.053) mg] among the control,low,medium and high arsenic exposure groups,the differences were statistically significant (Hc =256.041,88.615,218.610,all P ＜ 0.01).Compared the levels of H2AK119ub [1.231 (0.856,1.817),1.244 (0.792,1.884),1.376 (0.743,1.981),1.390 (0.906,2.045)],H2BK120ub [0.350 (0.186,0.589),0.363 (0.152,0.678),0.428 (0.134,0.788),0.276 (0.146,0.453)] in human peripheral blood leukocytes among control,low,medium and high arsenic exposuregroups,the differences were not statistically significant (Hc =2.130,4.330,all P ＞ 0.05).There were no correlations between H2AK119ub and water arsenic content,water arsenic accumulative intake (r =0.104,-0.008,all P ＞ 0.05);there was a positive correlation between H2AK119ub and urinary arsenic content (r =0.166,P ＜ 0.05).There were negative correlations between H2BK120ub and water arsenic content,water arsenic accumulative intake (r =-0.183,-0.159,all P ＜ 0.05);there was no correlation between H2BK120ub and urinary arsenic content (r =-0.101,P ＞ 0.05).There was a negative correlation between H2AK119ub and H2BK120ub (r =-0.127,P ＜ 0.05).Conclusion External exposure to arsenic may change the levels of H2BK120ub in human peripheral blood leukocytes.

Objective To investigate the effects of fluoride on trabecular bone of the tibia and lumbar in BALB/c mice.Methods Totally 64 four-week-old BALB/c mice were randomly divided into 4 groups by weight,16 per group:control group (treated with distilled water) and 3 sodium fluoride (NaF) exposure groups (treated with NaF at 25,50 and 100 mg/L F-),respectively.At 12 weeks,mice were killed and blood,two hind limbs and lumbar were collected.Bone fluoride content and incidence rates of dental fluorosis were determined.Serum content of alkaline phosphatase (AKP) and acid phosphatase (ACP) were detected by micro enzyme labeled method.The ultrastructure of osteoblasts and osteoclasts in lumbar were observed via transmission electron microscope.The pathological changes of the trabecular bone of the tibia and the lumbar were observed under optical microscope,the percentage of trabecular area (％Tb.Ar) was measured with Image-Pro Plus (IPP) software.Results Bone fluoride contents of low,middle and high fluoride groups [(1 828.62 ± 102.93),(3 308.27 ± 185.63),(4 933.36 ± 301.16) mg/kg] were higher than that of the control group [(775.23 ± 92.56) mg/kg,all P ＜ 0.05].The incidences of dental fluorosis in the 4 groups were 0(0/16),47％(7/15),93％(14/15) and 100％(16/16),respectively;the difference was statistically significant (x2 =27.23,P ＜ 0.05).In middle and high fluoride groups,serum AKP [(18.30 ± 1.99),(24.50 ± 3.14) king unit/100 ml] and ACP [(11.97 ± 1.73),(11.31 ± 1.46) king unit/100 ml] were significantly higher than those of control [(14.63 ± 1.21),(9.07 ± 1.47) king unit/100 ml,respectively,all P ＜ 0.05].Under the electron microscope,osteoblast had developed organelles in each fluoride group,rough endoplasmic reticulum,Golgi body,and mitochondria were abundant,and nucleolus was obvious in the osteoblast.Osteoclast was rich in mitochondria,ruffled border clear and distributed phagocytic vacuoles in low fluoride group and middle fluoride group.Compared with the control group (17.03 ± 3.73),HE staining of tibia ％Tb.Ar in high fluoride group (28.79 ± 8.26) was significantly increased (P ＜ 0.05).The lumbar spine ％Tb.Ar in low,middle and high fluoride groups (15.87 ± 2.59,18.28 ± 0.89,21.99 ± 1.81) were higher than that of the control group (12.06 ± 1.76,all P ＜ 0.05].Conclusions BALB/c mice could be used as a model of skeletal fluorosis.Osteoblast and osteoclast are activated in BALB/c mice with skeletal fluorosis.Bone formation is more obvious than bone resorption and bone mass is increased.What is more,bone mass has increased more significantly in the lumbar spine of mice.

BACKGROUND:Among the pathogenic factors of cervical spondylosis,herniation of the intervertebral disc,dislocation of the facet joint and the stenosis of the intervertebral foramen are important factors leading to symptoms in patients.Moreover,inappropriate manipulation may aggravate the possibility of cervical disc rupture,leading to exacerbation of symptoms in patients. OBJECTIVE:To compare the effect between sagittal cervical manipulation and traditional cervical rotation manipulation on the area of the intervertebral disc,facet joint and intervertebral foramen at the operative segment by the finite element analysis. METHODS:The neck CT data of a male volunteer with a normal neck were selected and imported into Mimics 17.0 three-dimensional reconstruction software.Geo-magic Studio 12.0,Solidworks 2017 and Ansys Workbench 17.0 software were used for the construction of the finite element model of cervical vertebrae(C3-6)including intervertebral disc and articular cartilage.The lower end plate of the C5 vertebral body was fixed.A uniformly distributed vertical downward 50 N load was applied on the upper surface of the upper vertebral body(C3).The stress,deformation and deformation direction of the C4-5 intervertebral disc,joint capsule stress,the displacement of facet joints and the area of bilateral intervertebral foramen were compared between sagittal cervical manipulation and traditional rotation reduction. RESULTS AND CONCLUSION:(1)When using the rotation technique,the maximum normal equivalent stress(von Mises stress)of the C4-5 disc was 8.06 MPa;the total deformation was 1.05 mm,and the fiber ring expanded to the left and outside.When using the sagittal tip lifting technique,the maximum normal equivalent stress(von Mises stress)of the C4-5 disc was 2.60 MPa;the total deformation was 0.90 mm,and the fiber ring expanded to the left and back.Compared with the rotation technique,the pressure of the cervical manipulation technique on the disc was less(about 32.3%of the rotation technique),and the deformation degree of the disc was also light(about 85.7%of the rotation technique).(2)When the rotation technique was used,the maximum stresses of the left and right articular capsule ligaments were 0.37 MPa and 1.69 MPa,respectively.The overall displacement of the facet joint was 2.21 mm.The area of the right intervertebral foramen decreased by about 3.8%and the area of the left intervertebral foramen increased by about 0.9%.When the sagittal end lifting manipulation was performed,the maximum stresses of the left and right articular capsule ligaments were 0.27 MPa and 1.70 MPa,respectively;the overall displacement of the facet joint was 1.63 mm;the area of the right intervertebral foramen increased by about 2.6%,and the area of the left intervertebral foramen decreased by about 0.9%.Compared with rotation manipulation,sagittal end lifting manipulation had fewer changes in the displacement of facet joint,joint capsule stress and intervertebral foramen area,so it was safer to operate.(3)In conclusion,compared with cervical rotation manipulation,sagittal end lifting manipulation has fewer changes in facet joint displacement,intervertebral disc stress/deformation degree,joint capsule stress,and foraminal area.In clinical practice,more appropriate manipulation should be selected based on biomechanical results after an accurate assessment of patients'conditions.

Objective To investigate the relationship between single nucleotide polymorphism(SNP)of the peroxisome proliferator activated receptor γ (PPARγ) gene Rs1801282 and brick-tea type fluorosis. Methods From 2012 to 2013, this cross-sectional study was performed in 16 endemic fluorosis areas of brick-tea type in Inner Mongolia Autonomous Region,Qinghai and Xinjiang Uygur Autonomous Region of China,to select adults>18 years old as subjects, who were diagnosed as skeletal fluorosis by X-ray. All of the subjects filled in demography survey questionnaire; the survey contents included general characteristic s, and average daily brick tea intake. Drinking tea samples and urine samples of each subject were collected, and fluoride content of urine and brick-tea was determined via the ion selective electrode method (WS/T 89-2006). X-ray scintigraphy was used to diagnose skeletal fluorosis, according to the "Diagnostic Criteria of Endemic Skeletal Fluorosis" (WS/T 192-2007); the subjects were divided into skeletal fluorosis group (case group) and non-skeletal fluorosis group (control group). To collect venous blood 5 ml, whole blood DNA was extracted, and polymorphism at Rs1801282 of PPARγ was detected by MassARRAY time-of-flight mass spectrometry, to calculate odds ratio (OR) and 95% confidence interval (CI). Results There were 1 414 people included in this study,including 347 in case group and 1 067 in control group. By the Hardy-Weinberg balance test, the PPARγ gene Rs1801282 genotype was representative in case group, control group and each nationality (P > 0.05). The difference of PPARγ gene Rs1801282 genotype in case group and control group was not statistically significant (OR was 0.991, 95%CI: 0.704 - 1.395, the adjusted OR was 1.026, 95%CI: 0.707-1.489).The difference of PPARγ gene Rs1801282 genotype(CC,CG+GG)in case group and control group in different nationality was not statistically significant (Tibetan: OR was 1.400, 95%CI: 0.576 - 3.404, the adjusted OR was 1.258, 95%CI: 0.474 - 3.340; Kazak: OR was 0.898, 95%CI:0.516 -1.562,the adjusted OR was 0.936,95%CI:0.532 -1.648;Mongolia: OR was 1.148,95%CI:0.508-2.594, the adjusted OR was 1.644, 95%CI: 0.683 - 3.956; Han: OR was 1.058, 95%CI: 0.451 - 2.482, the adjusted OR was 0.959, 95%CI: 0.388 - 2.371; Russian: OR was 0.000, 95%CI: 0.000 - 0.000, the adjusted OR was 0.000, 95% CI: 0.000 - 0.000) with binary Logistic regression analysis. Conclusion We have found no association between SNP of PPARγ gene Rs1801282 and skeletal fluorosis of brick-tea type fluorosis in China.

Objective To study the urinary arsenic safety guideline value of a population for evaluating the arsenic exposure level in a certain population and providing evidence for the implementation of prevention and control measures in endemic arsenicosis area.Methods According to the data from the national high-arsenic drinking water sources screening in endemic arsenicosis area of drinking water type and quality supervision and inspection for water-improving project to decrease arsenic from 2005 to 2014,census data on arsenic poisoning in endemic arsenicosis area,data on surveillance of endemic arsenicosis,10 722 people with detailed personal information,complete water arsenic exposure data and accurate urinary arsenic detection data were selected to be the research objects.The relationship between urinary arsenic and water arsenic was analyzed based on the surveillance data of 4 501 people from 2013 to 2014.The safety guidance value of urinary arsenic was determined based on the geometric mean value of urinary arsenic in people exposed to water arsenic in the range of (0.050 ± 0.005) mg/L,and verified using the data of 6 221 people from 2005 to 2012.Every time,a random sample of 2 000 people was taken as the verification sample,the sensitivity and specificity of the index for determining whether water arsenic exposure exceeded the standard were determined by area under the ROC curve (AUC),and a total of 10 sample tests was performed.Results When the water arsenic concentration was less than 0.01 mg/L,the correlation coefficient of water arsenic concentration with urinary arsenic concentration was 0.097 (P ＜ 0.01);when the water arsenic concentration was more than 0.01 mg/L and less than 0.05 mg/L,the correlation coefficient of arsenic concentration with water arsenic concentration was 0.456 (P ＜ 0.01);when the water arsenic concentration was more than 0.05 mg/L,the correlation coefficient of water arsenic concentration with urinary arsenic concentration was 0.630 (P ＜ 0.01).With increase of water arsenic concentration,the concentration of urinary arsenic increased significantly,and the difference was statistically significant (x2 =2 337.956,P ＜ 0.01).When water arsenic concentration was in the range of (0.050 ± 0.005) mg/L,the urinary arsenic geometric mean was 0.032 mg/L.AUC analysis of 10 random samples of 2 000 people showed that the geometric mean of urinary arsenic was 0.032 mg/L in the population,which can accurately distinguish whether the water arsenic level exceeded 0.05 mg/L,and the AUC value was higher than 0.94.And the sensitivity and specificity were achieved 0.898 and 0.844.Conclusions The geometric mean of urinary arsenic is 0.032 mg/L,which can be used as a safety guideline value for urinary arsenic in the population.When the geometric mean of urinary arsenic exceeds this value,the population may be exposed to high arsenic.

Objective To observe the effect of arsenic exposure to drinking water on thelevel of histone 3 lysine 4 trimethylation (H3K4me3) and histone 3 lysine 79 trimethylation (H3K79me3) in peripheral blood leukocytes of human,and to analyze the relationship between arsenic exposure and H3K4me3,H3K79me3 modification levels.Methods A cluster sampling survey was carried out in typical endemic arsenicosis areas of Shanxi and Jilin provinces.Two hundred eighty-one local residents with a drinking water age of ≥ 10 years were selected as the survey subjects.According to the arsenic content of drinking water,the tested population was divided into control group (water arsenic content ≤0.01 mg/L,60 cases),low water arsenic exposure group (＞ 0.01-0.05 mg/L,61 cases),medium water arsenic exposure group (＞ 0.05-0.10 mg/L,50 cases),and 110 cases of high water arsenic exposure group (＞ 0.10 mg/L).Drinking water samples,immediate urine samples and peripheral blood samples were collected from the subjects.Arsenic content in drinking water and urinary arsenic content were determined via the atomic fluorescence method;histone H3K4me3 and H3K79me3 in peripheral blood leukocytes were determined by dot blot hybridization (Dot Blotting).Results There were no statistically significant differences in age (61.50,60.00,59.50,59.50 years old),different gender (male:20,27,17,40 cases,female:40,34,33,70 cases),body mass index (BMI),smoking and drinking status between the control group,low,medium and high water arsenic exposure groups.Water arsenic content in the control group,low,medium and high water arsenic exposure groups (median:0.005,0.024,0.076,0.150 mg/L),urinary arsenic content (0.011,0.018,0.061,0.134 mg/L),and water arsenic cumulative exposure levels (0.342,1.641,5.273,7.716 mg) were compared between groups,the differences were statistically significant (H =256.041,88.615,218.610,P ＜ 0.01).In the control group,low,medium and high water arsenic exposure groups,the modification levels of H3K4me3 (0.100,0.059,0.083,0.083)and H3K79me3 (0.049,0.036,0.055,0.052) in peripheral blood leukocytes were not significantly different (H =1.488,2.097,P ＞ 0.05).The levels of H3K4me3 and H3K79me3 in peripheral blood leukocytes were positively correlated with water arsenic content,urinary arsenic content,water arsenic cumulative exposure levels (r =0.245,0.221;0.299,0.318;0.149,0.149;P ＜ 0.01 or ＜ 0.05);there was a positive correlation between H3K4me3 and H3K79me3 modification levels (r =0.811,P ＜ 0.01).Conclusion There is a positive correlation between arsenic exposure through drinking water and the levels of H3K4me3 and H3K79me3 in the peripheral blood leukocytes of the population,but it is necessary to expand the sample size for further study.

Objective To investigate the relationship between Cytochrome P-450 1A1 (CYP1A1) gene polymorphism and the ethnic differences to brick-tea fluorosis and the gene-environment interaction.Methods Inhabitants over the age of 16 years old in Inner Mongolia,Qinghai and Xinjiang were investigated.The questionnaire survey included basic information,dietary survey and total fluoride intake,and peripheral venous blood was collected.The CYP1A1 gene single nucleotide polymorphism (SNP) genotyping was determined using mass spectrometry;the diagnosis of skeletal fluorosis was based on the X-ray method;combined genetic factors with environmental factors,the interaction of gene-environment was analyzed.Results In the 1 414 copies of whole blood samples (308 Tibetans,290 Kazakhs,261 Mongolians,425 Han people,130 Russians),CYP1A1 genes rs1048943 sites were typed into AA,AG and GG genotypes,and gene distribution met Hardy-Weinberg equilibrium (P ＞ 0.05).The frequencies of genotypes AA,AG and GG in Tibetans were 55.8％ (172/308),37.3％ (115/308) and 6.8％ (21/308),respectively;the frequencies of the three genotypes in Kazakhs were 69.7％ (202/290),27.6％ (80/290) and 2.8％ (8/290),respectively;the frequencies of the three genotypes in Mongolians were 60.5％ (158/261),36.0％ (94/261) and 3.4％ (9/261),respectively;the frequencies of the three genotypes in Han people were 60.9％ (259/425),33.6％ (143/ 425) and 5.4％ (23/425),respectively;the frequencies of genotypes in Russians were 72.3％ (94/130),26.9％ (35/130) and 0.8％ (1/130),respectively;the differences of the three genotype frequencies between different ethnic groups were statistically significant (x2 =24.757,P ＜ 0.05).The skeletal fluorosis detection rates in different ethnic from high to low were Tibetans (39.94％,123/308),Kazakhs (33.79％,98/290),Mongolians (22.22％,58/261),Han people (13.41％,57/425) and Russians (8.46％,11/130),and the differences were statistically significant (x2 =100.156,P＜ 0.05).Skeletal fluorosis detection rates of different genotypes were AA (24.18％,214/885),AG/GG (25.14％,133/529),the difference was not statistically significant between the groups (x2 =0.165,P ＞ 0.05).After the ethnic stratification,the differences were also not statistically significant (P ＞ 0.05).Only in the group of Tibetans whose urine fluoride level was 1.6-3.2 mg/L and Mongolians under age 45 were found that the G gene was one of the risk factors in skeletal fluorosis [OR =2.035,95％ CI (1.003-4.128);OR =5.602,95％CI (1.461-21.479)];G gene might be a protective factor in the Mongolians aged 45 years and over [OR =0.422,95％CI(0.190-0.938)].Conclusion This study does not find a positive correlation between CYP1A1 gene polymorphism and the ethnic differences to bricktea fluorosis.