Objective To investigate the expressions of receptor for advanced glycation endproducts (RAGE) and nuclear factor κB(NF-κB) in brain hippocampus of rat with chronic fluorosis,and to reveal the mechanism of brain damage resulted from chronic fluorosis.Methods Sixty clean grade SD rats were randomly divided to three groups(20 rats in each group,10 female and 10 male) fed with different contents of fluoride,control group with normal tap-water(＜ 0.5 mg/L fluoride),small dosage of fluoride exposure group(10 mg/L fluoride in tap-water) and large dosage of fluoride exposure group(50 mg/L fluoride) for six months.Then the rats were killed by femoral artery bleeding and hippocampus was removed.Protein and mRNA levels of RAGE and NF-κB in the hippocampus were determined by Western blotting and quantitative real time PCR,respectively.Results As compared to the control groups[(100.00 ± 2.60)％,(100.00 ± 7.80)％],the expressions of RAGE and NF-κB at protein level in the hippocampus were significantly increased in the small dosage of fluoride exposure groups [(205.00 ± 15.30)％,(156.00 ± 12.20)％] and the large dosage of fluoride exposure groups[(232.00 ± 10.90)％,(162.00 ± 9.80)％,all P ＜ 0.05]; for the mRNA level of RAGE and NF-κB,the expressions were higher in the small dosage of fluoride exposure groups(1.27 ± 0.09,0.83 ± 0.15) and the large dosage of fluoride exposure groups (2.60 ± 0.19,1.27 ± 0.19) than those of the control groups(0.66 ± 0.18,0.32 ± 0.08,all P＜ 0.05).Conclusions The increased expressions of RAGE and NF-κB in the hippocampus of rat brain are caused by chronic fluorosis,and these changes may be associated with the mechanism of nerve injury.

Objective Aim of the study is to investigate the expression of syndecan-4 and nuclear factor κB(NF-κB) in the kidney of rat with chronic fluorosis,and to reveal the mechanism of kidney damage resulted from the toxicity of excessive amount of fluoride.Methods According to body mass and sex,sixty SD rats were randomly divided to three groups according to body mass and fed with different contents of fluoride:control group with normal tap-water(＜ 0.5 mg/L fluoride),small dosage of fluoride exposure group (adding 10 mg/L fluoride in tap-water) and large dosage of fluoride exposure group (50 mg/L fluoride) for six months.The protein level of syndecan-4 and NF-κB in the kidney was detected by Western blotting and syndecan-4 mRNA level by quantitative real time PCR.Results As compared to the control group[(100.0 + 8.1)％],the expression of syndecan-4 at protein level in the kidney of rat was significantly increased in the small dosage of fluoride exposure group [(198.5 + 5.6)％,P ＜ 0.05] and large dosage of fluoride exposure group [(209.2 + 13.0)％,P ＜ 0.05]; the protein levels of NF-κB in the small dosage of fluoride exposure group[(284.4 + 11.1)％,P ＜ 0.05] and in the large dosage of fluoride exposure group[(343.2 + 2.9)％,P ＜ 0.05] were significantly increased than that of the control group[(100.0 ± 10.7)％].The mRNA levels of syndecan-4 in the kidney in the small dosage of fluoride exposure group and large dosage of fluoride exposure group(0.431 + 0.058 and 0.453 ± 0.065,both P ＜ 0.05,respectively) were significantly increased than that of the control(0.128 + 0.026).Conclusions The increased expression of NF-κB in the kidney is induced by increased expression of syndecan-4,which may be involved in kidney damage of chronic fluorosis.

Objective The aim of the study was to investigate the expression of P-glycoprotein (P-gp)and nuclear factor κB (NF-κB) in the cerebral cortex of rat with chronic fluorosis,and to reveal the mechanisms of damaged nervous system resulted from the toxicity of fluoride.Methods Sixty SD rats were randomly divided into three groups.The rats in each group were given drinking water containing different levels of fluoride:control group less than 0.5 mg/L,small amount of fluoride exposure group 10.0 mg/L and large amount of fluoride exposure group 50.0 mg/L.The animals were examined at the sixth month after initiating the experiment.Protein levels of P-gp and NF-κB in brain tissues were detected by immunocytochemistry and Western blotting,and the P-gp protein and mRNA level by quantitative real time PCR method.Results As compared to the control group(28.21 ±6.13),the numbers of positive staining cells by P-gp antibody in the cortex of rat brains were significantly increased in both the small and the large amount of fluoride exposure groups[(48.46 ± 8.00),(53.72 ± 9.15),respectively,all P ＜ 0.05] ; the protein levels in the control group(100.00 ± 3.86)％ detected by Western blotting were significantly increased in the cortex of rat brains treated with fluoride in both the small and the large amount of fluoride exposure groups[(189.47 ± 3.14)％,(191.36 ± 11.09)％,respectively,all P ＜ 0.05].The significantly increased expression of NF-κB at the protein level was observed in the cortex of rat brains of the small and the large amount of fluoride exposure groups[(365.97 ± 6.04)％ and (417.15 ± 10.89)％,respectively] as compared with the control group[(100.00 ± 10.07)％,all P ＜ 0.05].The mRMA level of P-gp in the cortex of rat brains of the small and the large amount of fluoride exposure groups(2396 ± 427,3479 ± 371,respectively) were higher than that of the control group(260 ± 106,all P ＜ 0.05).Conclusion The increased expressions of P-gp and NF-κB in the cortex of rat brains are induced by chronic fluorosis,which might be connected with the mechanism of brain damages.

Objective To investigate the changes of reactive oxygen species(ROS) level and mitochondria fission-fusion-balance in cortical neurons of rats with chronic fluorosis and reveal the correlation between these two factors. Methods One hundred and twenty rats were randomly divided into 3 groups(control group, low-dose fluorosis group, high-dose fluorosis group) and 40 rats were in each group according to body weight and the experiments were carried out for 3 months or 6 months. The rats were fed with different concentrations of fluoride (NaF) to establish fluorosis models. Controls were fed with tap water( < 0.5 mg/L), experimental animals in low- or high-dose group were fed with water containing NaF 10.0,50.0 mg/L, respectively. The level of ROS and the morphology in mitochondria fission-fusion balance in neurons of the cortex of rat brains prepared with cortical frozen sections were detected with ROS fluorescent probe and MitoTracker RED probe, respectively. Results Significant differences of the level of ROS and the numbers of abnormal mitochondria in morphology in the cortical neurons were found between 3 groups at the experiment period of 3 month and 6 month(F= 3.07,3.06,3.05,3.07, all P < 0.05). As compared with control group(10.43 ± 5.98,4.12 ± 3.86) at the experiment period of 3 month, the level of ROS and the numbers of abnormal mitochondria in morphology in the cortical neurons were obviously increased in high-dose fluorosis group(25.48 ± 6.09,20.47 ± 6.09, all P < 0.05), whereas no significant changes were found in low-dose fluorosis group(11.67 ± 3.49,6.68 ± 3.48, all P> 0.05). Furthermore, the increases in both ROS level and abnormal numbers of mitochondria were significant observed in the cortical neurons of low-dose fluorosis group (63.02 ± 8.15, 49.33 ± 8.61) and high-dose fluorosis group(65.60 ± 7.40,53.10 ± 6.95) as compared with the control group (25.26 ± 6.41,20.26 ± 6.41) at the experimental period of 6 month (all P < 0.05). The abnormal numbers of mitochondria correlated with ROS level(r = 0.93,0.81, all P < 0.05). Conclusions Taking excessive amount of fluoride results in high level of oxidative stress and impaired the balance of mitochondrial fission-fusion,which is dependent on the feeding times and doses of fluoride. The mechanism of the mitochondrial abnormalities might be associated with the high level of oxidative stress induced by chronic fluorosis.

Objective To observe the expression of mitochondrial fission protein locus Fis1 and ultrastructural changes in the renal cells of rats with chronic fluorosis,and to reveal the mechanism in mitochondrial damage of the renal cells.Methods Sixty SD rats were randomly divided into 3 groups according to sex and body mass(20 in each group):control group,lower fluoride group and higher fluoride group.All the rats were fed with different doses of sodium fluoride in drinking water(0,10 and 50 mg/L,respectively).Six-month later,the expression of Fisl in renal cells was determined by real-time fluorenscence quantitative PCR and immunohistochemistry technology,the mitochondrial morphology of renal cells was observed under transmission electron microscopy (TEM).Results As compared with the control group(28.70 ± 12.41),Fis1 mRNA levels(91.48 + 34.83 and 582.09 ± 184.69) in renal cells of the lower fluoride and the higher fluoride groups were increased(all P ＜ 0.05).As compared with the control group(10.49 ± 7.66),Fisl protein levels(16.33 ± 10.26 and 21.50 ± 5.24) in renal cells of the lower fluoride and the higher fluoride groups showed a trend of increasing,the higher fluoride group was higher than that of the control group(P ＜ 0.05).By TEM,mitochondrial crest in renal cells of the lower fluoride and the higher fluoride groups was vague or disappeared,mitochondrial division section appeared.Conclusions Fluoride is a kind of toxicant that can cause damage to mitochondrion of renal cells,induce the expression of Fis1 in transcriptional and protein level,and lead to the obstacles of mitochondrial fusion-fission and ultrastructural abnormality of mitochondrion,which may play an important role in mechanism of mitochondrial damage in the renal cells of rats with chronic fluorosis.

ObjectiveTo investigate the transcriptional changes of nitochondria fission and fusion gene loci and reactive oxygen species (ROS) level in cortical neurons of rats with chronic fluorosis,and to reveal their roles in mitochondria damage due to chronic fluorosis.MethodsSD rats were fed with different doses of fluoride through drinking water[＜ 0.5(control),10,50 mg/L,respectively] for 3 and 6 months.The level of ROS and mRNA contents of mitochondria fission gene loci Drp1/Fis1 and fusion gene locus Mfn1 in the cortical neurons of rat brains were detected with ROS fluorescent probe and real-time PCR,respectively.ResultsAs compared with control group [10.43 ± 5.98,(3.4 ± 0.6) × 103,(8.8 ± 1.4) × 10,(1.2 ± 0.2) × 102] at the experiment period of 3 months,the level of ROS and mRNA contents of mitochondria fusion gene locus Mfn1 and fission gene loci Drp1/Fis1 in the cortical neurons were obviously increased in the rats fed with 50 mg/L fluoride through drinking water[25.48 ± 6.09,(1.0 ± 0.2) × 1011,(3.0 ± 1.6) × 103,(8.9 ± 3.6) × 102,all P ＜ 0.05],whereas no significant changes were found in the rats fed with 10 mg/L fluoride[11.67 ± 3.49,(3.1 ± 0.3) × 104,(6.7 ± 2.7) × 10,(5.0 ± 0.9) × 10,all P ＞0.05].Furthermore,at 6 months of the experiment the increases in ROS level(63.02 ± 8.15,65.60 ± 7.40) and mRNA contents of mitochondria fission gene loci Drp1/Fis1 [(2.0 ± 0.8) × 106,(4.0 ± 0.6) × 105,(3.8 ± 1.3) × 103,(1.3 ± 0.2) × 103] and the decrease in mitochondrial fusion gene locus Mfn1[(3.0 ± 0.4) × 106、(4.0 ± 0.9) × 104]were observed in the cortical neurons of the rats fed with 10 mg/L and 50 mg/L fluoride as compared with the control group[25.26 ± 6.41,(3.0 ± 0.8) × 109,(5.1 ± 0.8) × 103,(2.8 ± 0.7) × 102,all P ＜ 0.05].Conclusions Excessive intake of fluorine leads to elevated ROS levels,and decreased transcription of mitochondrial fusion gene loci Mfn1,which is positively correlated with the time and dose-exposed to fluoride.The changes of mitochondrial fission and fusion gene loci in the cortical neurons may be related to high level of oxidative stress induced by chronic fluorosis.

Objective To investigate the deletion pattern of 4.8 kb mitochondrial DNA(mito-DNA) in liver,kidney,and brain of rats with chronic fluorosis and to explore the significance of mitochondria in the pathogenesis of chronic fluorosis.Methods Sixty SD rats were randomly divided into 3 groups according to body mass (20 in each group):control,low-fluoride and high-fluoride groups,and they were fed with different concentrations of fluoride in drinking water (0,10,50 mg/L,respectively) for 6 months.Mito-DNA in liver,kidney and brain was detected by real-time PCR.Results The amounts of 4.8 kb mito-DNA in liver(2.1 × 10-3,1.6 × 10-3),kidney (1.7 × 10-3,1.4 × 10-4) and brain cortex (1.5 × 10-5,1.3 × 10-5) in low-and high-fluoride groups were significantly reduced,as compared with that of control group (2.9 × 10-3,2.0 × 10-3,1.1 × 10-4,all P ＜ 0.05).The amount of 4.8 kb mito-DNA in kidney in high-fluoride group was lower than that in low-fluoride group (P ＜ 0.05).Conclusions Excessive fluoride intake can result in missing of 4.8 kb mito-DNA in liver,kidney and brain cortex.The abnormal of mito-DNA might be related to the dysfunction of mitochondrial respiratory chain.

OBJECTIVETo observe the mitochondrial fragmentation and the expression of mito-fusion 1 gene in the cortical neurons of rats with chronic fluorosis, and to reveal their roles in mitochondria damage to neurons due to chronic fluorosis.

METHODSSD rats were divided randomly into three groups of 20 each (a half females and a half males housed individually in stainless-steel cages), and fed with the different doses of fluoride containing in drinking water (untreated control containing 0 mg/L fluoride, and low-fluoride and high supplemented with 10 and 50 mg/L fluoride, respectively). After 3 or 6 months exposure, the mitochondrial morphology of the neurons in rat brains were observed by transmission electron microscopy (TEM), then the expression of mitochondrial fusion gene, Mfn1, were detected by immunohistochemistry and western-blotting, respectively.

RESULTSDental fluorosis was obvious in the rats exposed to excessive fluoride in their drinking water, that is, (16 rats out of 20) numbers of I° detal fluorosis in the low-fluoride group, and (11 rats out of 20) numbers of I° and (9 rats out of 20) numbers of II° detal fluorosis in the high-fluoride group were observed after 3 months exposure. Moreover, (14 rats out of 20) numbers of I° and (6 rats out of 20) numbers of II° detal fluorosis in the low-fluoride group and (6 rats out of 20) numbers of Io, (13 rats out of 20) numbers of II°, and (1 rats out of 20) numbers of III° detal fluorosis in the high-fluoride group were observed after 6 months exposure. And both of untreated controls without detal fluorosis were also observed. The urinary level of fluoride in the low-fluoride group (3.30 ± 1.18) mg/L and in the high-fluoride group (5.10 ± 0.35) were observed after 3 months exposure (F = 3.18, P < 0.05). Moreover, the urinary level of fluoride in the low-fluoride group (4.16 ± 1.39) mg/L and in the high-fluoride group (5.70 ± 1.70) mg/L were also observed after 6 months exposure (F = 3.17, P < 0.05). The normal mitochondrial morphology of neurons in rats without fluorosis was observed after 3 and 6 months, while the abnormal mitochondrial morphology of neurons with fluorosis was shown, presenting mitochondrial fragmentation with swollen cristae and even the fragmented, shortened or stacked punctuate membranes (section observation of three bullous mitochondrial-mitochondrial fission process) by TEM. As compared with controls (53.0 ± 4.54 and 1.21 ± 0.18) at the experiment period of 3 months, Mif1 protein analysis with immunocytochemical (the numbers of positive cells: 51.09 ± 6.25) and western-blotting (1.22 ± 0.26) were no significant difference for low fluoride group (t = 1.7, 1.1, P > 0.05); Mif1 protein analysis with immunocytochemical (the numbers of positive cells: 59.71 ± 5.64) and western-blotting (1.66 ± 0.20) were significantly increasing for high fluoride group (t = 2.1, 2.1, P < 0.05). As compared with controls (36.43 ± 4.04 and 1.00 ± 0.13) at the experiment period of 6 months, Mif1 protein analysis with immunocytochemical (the numbers of positive cells 20.05 ± 4.55 and 17.10 ± 3.86) and western-blotting (0.64 ± 0.08 and 0.39 ± 0.06) were significantly decreasing for the two fluoride group (t = 2.1, 2.2; 2.2, 2.2 respectively, all P value were < 0.05).

CONCLUSIONSTaking excessive amount of fluoride might result in the mitochondrial fragmentation for the changed expression of Mfn1, and the neurons damage from the chronic fluorosis might be associated with the dysfunction of mitochondrial fusion.

Animals ; Drinking Water ; chemistry ; Female ; Fluoride Poisoning ; metabolism ; pathology ; Fluorosis, Dental ; metabolism ; Male ; Membrane Proteins ; metabolism ; Mitochondria ; pathology ; Mitochondrial Proteins ; metabolism ; Neurons ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley

Nowadays, the injury in human mitochondrial DNA (mtDNA) is well known to accumulate in various tissues with age. It's significant to further investigate and then apply it to estimation of the age at parenchymas.
Aging/physiology* ; Base Pair Mismatch/genetics* ; DNA Damage/physiology* ; DNA Fragmentation/genetics* ; DNA, Mitochondrial/physiology* ; Gene Deletion ; Humans ; Polymerase Chain Reaction

It's always a challenge to type from highly degraded biological remains. PCR-based STR genotyping is helpful and valuable for such degraded samples like bones, teeth et al, but the typing results are sometimes unstable or wrong. Here the methods for solving the problems and improving reproducibility are reviewed.
Bone and Bones ; DNA/analysis* ; DNA Degradation, Necrotic ; DNA Fingerprinting/methods* ; Forensic Anthropology ; Genetic Markers ; Humans ; Polymerase Chain Reaction/methods* ; Polymorphism, Single Nucleotide ; Tandem Repeat Sequences ; Tooth/chemistry*