Objective:To investigate the association between relative mitochondrial DNA copy number (mtDNA-CN) and coal-burning-borne endemic fluorosis (abbreviated as coal-burning-borne fluorosis).Methods:From June 2018 to March 2019, using cross-sectional study, 482 patients with coal-burning-borne fluorosis were selected as the case group in Bijie City, a typical coal-burning-borne fluorosis area of Guizhou Province; meanwhile, 212 healthy individuals from Changshun County, a non-coal-burning-borne fluorosis area in Guizhou Province, were selected as the control group. Questionnaire survey and physical examination were used to collect general condition such as basic information and living habits of the two groups, peripheral venous blood samples were collected, and real-time fluorescence quantitative PCR was used to detect the relative mtDNA-CN in peripheral blood. The correlation between relative mtDNA-CN and coal-burning-borne fluorosis was analyzed by binary and unordered multi-class logistic regression.Results:There were significant differences in the body mass index (BMI), and the distribution of gender rario, marital status and education level between the control group and the case group ( t = 7.91, χ 2 = 5.11, 13.33, 34.32, P < 0.05). The relative mtDNA-CN in the control group was higher than that in the case group [median (quartile): 202 (138, 292) vs 131 (96, 217), Z = - 7.80, P < 0.001]. The results of binary logistic regression analysis [odds ratio (95% confidence interval)] showed that educational level [primary school: 0.572 (0.377 - 0.868), junior high school and above: 0.292 (0.174 - 0.493)], relative mtDNA-CN [131 - < 217: 0.265 (0.144 - 0.488), ≥217: 0.183 (0.100 - 0.335)] and BMI [1.222 (1.142 - 1.307)] were the influencing factors for the risk of coal-burning-borne fluorosis( P < 0.05). In subgroups with different BMI and educational levels, the relative mtDNA-CN was significantly negatively correlated with the risk of coal-burning-borne fluorosis( Ptrend < 0.05), and there was no interaction between mtDNA-CN and BMI and educational levels ( Pinteraction > 0.05). The results of unordered multi-class logistic regression analysis showed that the relative mtDNA-CN were significantly negatively correlated with the risk of dental fluorosis and skeletal fluorosis ( Ptrend < 0.05). Conclusion:The higher the relative mtDNA-CN, the lower the risk of coal-burning-borne fluorosis, suggesting that mtDNA-CN may be a potential biomarker of coal-burning fluorosis.

Objective:To explore the relationship between children's intelligence and urinary fluoride in Suojia Township of Miao, Yi and Hui Nationalities (referred to as Suojia Township), a coal-burning-borne endemic fluorosis area in Guizhou Province.Methods:In April 2019, 173 children aged 10 to 13 years old were selected from three schools in Suojia Township. According to whether they had dental fluorosis, the children were divided into case group ( n = 104) and control group ( n = 69). Middle segment urine samples of the children were collected and urinary fluoride level was determined by the method of ion-selective electrode. Combined Raven's Test-the Rural in China (CRT-RC2) was used for children's intelligence quotient (IQ) test. Linear regression analysis was used to observe the association between urinary fluoride and IQ, and the results were expressed by regression coefficient ( β) and 95% confidence interval ( CI). Results:Urinary fluoride level of case group was higher than that of control group [(2.14 ± 1.78) vs (1.53 ± 0.98) mg/L], and IQ was lower than that of control group [(92.33 ± 11.68) vs (100.38 ± 11.87) points], and the differences were statistically significant ( t = 2.58, 4.41, P < 0.05). The linear regression equation of urinary fluoride ( X) and IQ ( Y) of case group was Y = 96.99 - 2.86 X. For every 1 mg/L increase in urinary fluoride level, IQ decreased by 2.86 points ( β = - 2.86, 95% CI: - 5.48 - - 0.24). Conclusion:Long-term exposure to fluoride pollution from coal burning may damage children's intelligence, and children's IQ decreases with increase of fluoride level in urine.

Objective:To investigate the relationship between gene polymorphism of osteoprotegerin (OPG) and coal-burning endemic fluorosis in Guizhou Province.Methods:In 2018 and 2019, a case-control study was conducted in Bijie City, a typical coal-burning endemic fluorosis area in Guizhou Province, and 260 cases of coal-burning endemic fluorosis patients were selected as case group. According to the "Diagnostic Criteria for Endemic Skeletal Fluorosis" (WS 192-2008), the case group was divided into severe group (130 cases) and mild group (130 cases). At the same time, 130 cases without dental fluorosis and skeletal fluorosis symptoms were chosen as control group in Changshun County, a non-coal-burning endemic fluorosis area in Guizhou Province. Whole blood genomic DNA was extracted, and real-time fluorescence quantitative PCR with TaqMan-MGB probe was utilized to type the OPG gene rs2460985, rs2073618, rs6469804 and rs6993813 four single nucleotide polymorphism (SNP) loci of all samples, and genetic model analysis was performed to compare the frequency distribution of its alleles, genotypes and constructed haplotypes in control, mild and severe groups. Results:By Hardy-Weinberg equilibrium test, the genotype frequencies of the four SNP loci all reached genetic balance in control, mild and severe groups ( P > 0.05). There was a statistically significant difference in the genotype frequency of OPG gene rs6469804 locus among the three groups (χ 2 = 10.615, P < 0.05), and the difference in the genotype frequency of this locus between the control group and the severe group was statistically significant (χ 2 = 6.784, P < 0.05). The results of genetic model analysis showed that in comparison between the control group and the severe group, the optimal genetic model of rs6469804 locus was the overdominant genetic model, the frequency distribution of genotypes AA + GG and AG in the control group and the severe group was statistically significant [odds ratio ( OR) = 1.94, 95% confidence interval ( CI): 1.16 - 3.23, P < 0.05], genotype AG was a risk factor for coal-burning endemic fluorosis. In comparison between the control group and the mild group, the optimal genetic model of rs2073618 locus was the recessive genetic model, the frequency distribution of genotypes GG + GC and CC in the control group and the mild group was statistically significant ( OR = 3.17, 95% CI: 1.08 - 9.30, P < 0.05), genotype CC was a risk factor for coal-burning endemic fluorosis. In comparison between the control group and the mild group, haplotypes C-C-G-T and T-G-A-C were risk factors for coal-burning endemic fluorosis (adjusted OR = 2.41, 1.98, 95% CI: 1.29 - 4.50, 1.22 - 3.23, P < 0.05); in comparison between the control group and the severe group, haplotype T-G-A-C was a risk factor for coal-burning endemic fluorosis (adjusted OR = 1.87, 95% CI: 1.14 - 3.07, P < 0.05). Conclusion:OPG gene rs6469804 locus genotype AG and rs2073618 locus genotype CC may be risk factors for coal-burning endemic fluorosis.

Objective To investigate the possible pathological role of mitochondrial apoptosis pathways and its factors in fluorosis-induced apoptosis of human hepatocellular carcinoma cell strain (HepG2).Methods Under the stimulation of 1,3,6 and 9 mmol/L concentrations of NaF in vitro for 24 h (n =5),while normal control group was cultured under normal condition,the cytotoxicity was measured with MTT.The mitochondrial apoptosis inducing factor (AIF) was measured at both mRNA (n =5) and protein levels (n =6),respectively,by real-time PCR and Western blotting.The mitochondrial apoptosis related factors,such as B-cells lymphoma-2 (Bcl-2),Bcl-associated X protein (Bax),cytochrome C,caspase-9 and caspase-3 were measured at protein levels (n =6).Results After treated with 0,1,3,6 and 9 mmol/L NaF for 24 h,the cell absorbance of HepG2 cells was 0.307 ± 0.031,0.333 ± 0.028,0.230 ± 0.011,0.178 ± 0.001 and 0.152 ± 0.003,respectively,and the differences were statistically significant among groups (F =82.224,P ＜ 0.01).After treated with 3 mol/L NaF for 24 h,the mRNA level of AIF was [(153.14 ± 5.41)％] which was increased compared to the control group [(100.00 ± 4.70)％,t =-4.73,P ＜0.05].Under the same condition,the protein levels of AIF,Bcl-2,cytochrome C in cytoplasm,caspase-9 and caspase-3 were (152.16 ± 47.30)％,(171.90 ± 51.52)％,(458.00 ± 19.48)％,(527.17 ± 200.67)％ and (432.70 ±64.27)％,which were increased compared to those of the control groups [(100.00 ± 48.86)％,(100.00 ± 34.44)％,(100.00 ± 116.59)％,(100.00 ± 19.58)％ and (100.00 ± 137.16)％,t =-3.80,-3.96,-15.76,-4.64,-5.06,all P ＜ 0.05],while the protein levels of Bax and cytochrome C in mitochondrion were (24.66 ± 26.04)％,(72.99 ±45.34)％,which were decreased compared to those of the control groups [(100.00 ± 44.01)％,(100.00 ± 34.14)％,t =6.35,0.68,all P ＜ 0.05].Conclusion The mitochondrial apoptosis pathway and related factors may be involved in NaF-induced cell death in HepG2 cells.

Objective To investigate the correlation between fibroblast growth factor receptor 2 (FGFR2) gene polymorphism and endemic fluorosis.Methods In Bijie City,Guizhou Province coal-burning-borne high fluoride areas,148 patients with fluorosis were selected as endemic fluorosis group;in non high fluoride areas of Changshun County of Guizhou Province,134 healthy people were selected as control group.Short tandem repeats (STRs)-PCR was utilized to detected the FGFR2 rs35668561 and D10S14839 microsatellite polymorphisms in endemic fluorosis cases and controls.Results FGFR2 rs35668561 461 bp (22AG)allele frequency of endemic fluorosis group (1.01％) was significantly lower than that of the control group (3.36％,x2 =5.29,P ＜ 0.05).FGFR2 D10S14839 286 bp (9GT),300 bp (16GT),310 bp (21GT) and 314 bp (23GT) allele frequency in the endemic fluorosis group were 14.53％,11.82％,16.89％ and 8.11％,in the control group were 22.01％,6.34％,8.96％ and 16.42％,the difference was statistically significant.Then 300 bp (16GT)and 310 bp (21GT)allele frequency of endemic fluorosis group was significantly higher than that of the control group (x2 =6.82,7.77,all P ＜ 0.05),and 286 bp (9GT),314 bp (23GT) allele frequency of endemic fluorosis group was significantly lower than that of the control group (x2 =5.32,9.16,all P ＜ 0.05).Conclusions FGFR2 rs35668561 and D10S14839 polymorphism are associated with endemic fluorosis.FGFR2 rs35668561 461 bp (22AG) allele may be a protective factor of endemic fluorosis.D10S14839 300 bp (16GT) and 310 bp (21GT) allele may be risk factors of endemic fluorosis,286 bp (9GT) and 314 bp (23GT) allele may be protective factors of endemic fluorosis.

Objective To explore the correlation between myeloperoxidase (MPO) genetic variation and coal-burning endemic fluorosis, and to understand the influence of integrated intervention including stove changes and health education on people’s health in the area. Methods In 2007, coal-burning endemic fluorosis disease areas were selected in Bijie City, Guizhou Province. No stove changes in Yachi Town, 150 patients with dental fluorosis were selected as fluorosis non-intervention group, and the intervention group was 150 patients in Changchun Town where the stoves were changed 2 years ago. The population in control group was selected in an area with non-endemic fluorosis in Changshun County. The mRNA expressions of MPO in leukoxytes were detected by real-time PCR. HepG2 cells were cultured in vitro and divided into four groups: pGL3-A group, pGL3-G group, pGL3-Control group and pGL3-Basic group. pGL3-A and pGL3-G were recombinant plasmid, while pGL3-Basic as a blank control and pGL3-Control as a positive one. The internal reference plasmid pRL-TK co-transfected the HepG2 cells with pGL3-G, pGL3-A, pGL3-Basic and pGL3-Control, respectively. The influence of sudden change of MPO gene promoter on the gene transfection activity was evaluated by a dual luciferasereporter gene system. Results The expression level of MPO mRNA in peripheral blood leukocytes in non-intervention group(0.054 ± 0 . 003 ) were higher than control and intervention groups (0.019 ± 0.004,0.019 ± 0.003, all P<0.05), and no significant change was found between intervention group and control group(P>0.05). After the MPO-463G/A locus genetic variation occured, the luciferase reporter gene expression level of the recombinant plasmid pGL3-G(0.753 4 ± 0.086 6) was higher than that of the pGL3-A(0.490 0 ± 0.022 3, P < 0.05). Conclusions The study on MPO gene promoter-463G/A locus has prompted that MPO gene allele may be a protective factor to coal-burning fluorosis. The integrated interventions have a role in the prevention and treatment of endemic fluorosis.

Objective To compare the transfection efficiency between different transfection methods in human HepG2 and SGC7901/ADM cells so as to provide experimental basis for further study .Methods To electrons fect the enhanced GFP plasmid into HepG2 and SGC7901/ADM cells by lipofection and electroporation methods ,respectively .The survival rates and transfection efficiency were analyzed .Results The efficiency of eGFP vector transfected into HepG2 cells by lipofection was (23 .8 ± 2 .1)% , compared with lipofection method ,the efficiency of eGFP plasmid transfected by electroporation was up to (49 .6 ± 2 .5)% ,and the difference was statistically significant(P<0 .05) .The efficiency of SGC7901/ADM cells by lipofection was (25 .4 ± 1 .3)% ,com‐pared with lipofection method ,the efficiency of electroporation was up to(52 .6 ± 2 .1)% ,and the difference was statistically signifi‐cant(P<0 .05) .This study provides reliable test parameters for electransfection of HepG2 and SGC7901/ADM cells .Conclusion The transfection efficiency of large fragment vector is efficiently improved by electroporation .

OBJECTIVETo analyze the population genetics characteristics of mitochondrial DNA (mtDNA) in Gelao, Mulao, Maonan ethnic groups from Guizhou.

METHODSMinisequenceing and restriction fragment length polymorphism (RFLP) were used to analyze 12 single nucleotide polymorphism (SNPs) of mitochondrial DNA in the 3 ethnic groups.

RESULTSA total of 30 haplotypes were detected in 156 samples. The distribution of H1, H23 had differed between Mulao, Maonan and Gelao, respectively, and so did M7 among the three groups. The difference was statistically significant (P < 0.05). Mulao, Maonan had respectively differed from Gelao and the difference was also statistically significant (P < 0.05).

CONCLUSIONThere was a great similarity in the distribution of haplotypes of the mtDNA among the three ethnic groups, except for some difference in the distribution of certain haplotypes.

Asian Continental Ancestry Group ; ethnology ; genetics ; China ; ethnology ; DNA, Mitochondrial ; genetics ; Humans ; Male ; Pedigree ; Polymorphism, Genetic

Objective To identify the distribution feature of methylenetetrahydrofolate reductase (M T HFR) gene polymorphism of Buyi ,Dong ,Miao nationality in Guizhou .Methods The MTHFR(677 and 1 298) genotypes of Buyi ,Miao and Dong healthy indi-viduals were determined by TaqMan-MGB probe genotyping method and constructed haplotypes .Results There were significant difference of MTHFR 677C/T genotype and allele frequencies among 3 groups(P<0 .05) ,There was significant difference of geno-type between Buyi and Miao nationality ,and there were significant differences of genotype frequencies in Buyi nationality and Dong and Miao nationality(P<0 .01) .There were no differences of MTHFR 1298A/C genotype frequencies among Buyi ,Dong and Miao nationality(P> 0 .05) .Buyi nationality had the lowest frequency in double wild homozygous type (677CC/1298AA) ,677TT/1298CC double mutation homozygous and 677TT/1298AC combination in above three minorities was not found .There were linkage disequilibrium between 677C/T and 1298A/C in Buyi and Miao nationality .Conclusion The genotypes frequencies of MTHFR 677T T/1298AC are significant differences among different regions and different ethnic groups .

Objective:To investigate the association between polymorphisms of FGFR2 and the susceptibility of breast cancer in Han population in Guizhou province.Methods:Genotyping was performed using PCR-sequence-specific primers(PCR-SSP)in 106 histologically confirmed breast cancer cases and 116 cancer-free controls.Results:The genotype frequencies of rs1219648 TT,TC,and CC were 50%,25.47%.and 24.53% in breast cancer cases and 29.31%,48.28%,and 22.41% in the controls.The gene frequencies of T in breast cancer cases and the controls were 62.74% and 53.45%.respectively.The gene frequencies of C were 37.26% and 46.55%.respectively.The distribution of allele and genotype frequencies of FGFR2 rs1219648 was statistically different between breast cancer cases and the controls(P<0.05).Conclusion:FGFR2 rs1219648 polymorphism influences the susceptibility of breast cancer.TT genotype might serve as a risk factor for breast cancer.