Change and relationship between Gli1 and β-catenin on rats' bone formation with chronic fluorosis / 中华病理学杂志

To investigate the change and association of glioma-associated oncogene homolog 1 (Gli1) and β-catenin on bone formation in rats with chronic fluorosis which were inhibited by cyclopamine (Cycl). Forty-eight Sprague-Dawley rats were evenly divided to four groups, including control, F, F+Cycl and F+DMSO groups. The control group were fed with tap water (NaF1 ppm). The F, F+Cycl and F+DMSO groups were exposed to NaF (50 ppm) in drinking water as the chronic fluorosis model. Then the rats in F+Cycl or F+DMSO groups were injected by Cycl or DMSO after 6 months, respectively. Urine fluoride concentration was detected using fluorine ion selective electrode. The enzyme-linked immunosorbent assay (ELISA) was used to detect bone alkaline phosphatase (BALP). Bone tissues were stained with hematoxylin-eosin. The mRNA and protein expression of Gli1 and β-catenin in bone tissue were detected using real-time PCR, immunohistochemistry and Western blot. Compared with the controls, the urine fluoride concentration and the width and volume of bone trabeculae were increased in the F, F+Cycl and F+DMSO groups, but no statistical difference among the 3 fluorosis groups. The concentration of BALP was increased in the F group and decreased in F+Cycl group (0.05). The expression of Gli1 and β-catenin mRNA and protein was higher in the F and F+Cycl groups than controls, but lower in the F+Cycl group than in the F group. There was positive correlation between the expression of Gli1 and β-catenin (0.476, 0.05). The expression of Gli1 and β-catenin was also associated with BALP concentration and volume of bone trabeculae, respectively (0.457, (2)0.466, 0.581, 0.554, respectively, 0.05 for all). The expression of Gli1 can be inhibited by Cycl. It may be involved in the bone formation of rats with chronic fluorosis. It may also affect the expression of β-catenin, which is an osteogenesis factor.

Effect of fluoride on expression of mRNA and protein of Wnt3a and β-catenin in osteoblast of rats / 中国地方病学杂志

Objective To explore the effect of excessive fluoride on expression of mRNA and protein of Wnt3a and β-catenin in rats' osteoblasts and its correlation with pathogenic mechanism of fluorosis.Methods Thirty-six healthy SD rats,weighting 100-120 g and according to body mass,were randomly divided into three groups(twelve in each group).The rats of control were fed wich tap water(fluoride ＜ 1 mg/L) and the experimental rats were exposed to NaF(low-fluoride group:5 mg/L,high-fluoride group:50 mg/L) added to the drinking water to establish the chronic fluorosis model.After fed for eight morth,all rats were killed and metaphysic of femoral was collected.Rat dental fluorosis was observed and bone fluorine was detected by ashing-fluorin ion selective electrode method.The content of bone alkaline phosphatase (BALP) and tartrate-resistant acid phosphatase 5b(TRACP 5b) in rats' serum was detected by enzyme-linked immunosorbent assay (ELISA).The morphologic changes of the bone were observed by microscopy.The expression of mRNA and protein of Wnt3a and β-catenin in osteoblasts of rats was analyzed with gray scale by hybridization in situ and immunohistochemistry methods,respectively.Results Detection rate of dental fluorosis,fluoride contents of urine and bone were significantly increased [control group:0.0％,(1.26 + 0.17)mg/L,(305.58 ± 91.26)mg/kg; low-fluoride group:66.7％,(2.06 ± 0.64)mg/L,(632.33 ±123.21)mg/kg; high-fluoride group:91.7％,(7.69 ± 1.96)mg/L,(1088.75 ± 156.16) mg/kg] in the rats treated with fluoride,the difference between groups was statistically significant(χ2 =21.6; F =36.57,467.02; all P ＜0.05).The contents of BALP and TRACP-5b in rats' serum were significantly different between groups(F =89.57,7.68; all P ＜ 0.05).Compared with control group[(16.24 + 1.57)U/L],the contents of BALP in rats' serum of the low-fluoride and high-fluoride groups[(31.47 ± 5.30) and (54.61 ± 2.27)U/L] were increased gradually(all P ＜0.05).Compared with the low-fluoride group,the value in the high-fluoride group decreased significantly (P ＜ 0.05).The contents of TRACP-5b in rats' serum of low-fluoride group[(3.45 ± 1.85)U/L] were elevated significantly(all P ＜ 0.05) compared with the control group[(1.26 ± 0.23)U/L] and the high-fluoride group[(2.74 ± 1.85)U/L].The bone cortices were thickened and the bone trabecula was broadened,arranged closely together in chronic fluorosis rats with significant difference compared with the control group.In the low-fluoride and high-fluoride groups,the expression levels of Wnt3a and β-catenin mRNA (low-fluoride group:132.87 ± 5.72 and 132.57 ± 9.56; highfluoride group:135.60 ± 6.64 and 137.87 ± 9.16) were markedly elevated with significant difference,respectively (F =12.47,5.96; all P ＜ 0.05) compared with those in control groups(119.86 ± 5.04 and 120.58 ± 7.84) by hybridization in situ(P ＜ 0.05),but there was no statistical significance (P ＞ 0.05) of the level of Wnt3a and β-catenin mRNA between low-fluoride and high-fluoride groups.In the low-fluoride and high-fluoride groups,the protein expression of Wnt3a and β-catenin (low-fluoride group:137.50 ± 4.32 and 140.85 + 3.54; high-fluoride group:142.65 ± 11.84 and 152.52 ± 4.64) were markedly elevated with significant difference,respectively (F =10.07,53.82; all P ＜ 0.05) compared with those in control group (124.01 ± 2.63 and 126.75 ± 4.65) by immunohistochemistry(all P＜ 0.05),Wnt3a protein production in the low-fluoride group was increased without statistical significance compared with the high-fluoride group (P ＞ 0.05).But the protein production of β-catenin in the lowfluoride group was elevated with significant difference compared with the high-fluoride group(P ＜ 0.05).The mRNA and protein production of Wnt3a were positively correlated with the mRNA and protein production of β-catenin (r =0.731,0.658; all P ＜ 0.05).Conclusions Rat bone tissue lesions caused by excessive fluoride may be associated with an increased expression of Wnt3a and β-catenin mRNA and protein in osteoblasts.In chronic fluorosis,fluoride stimulates the overexpression of Wnt3a and β-catenin in the Wnt signal transduction pathway,enhances bone osteogenesis and causes skeletal fluorosis.

Expression of mitochondrial fission protein locus Fis1 and ultrastructural changes in the renal cells of rats with chronic fluorosis / 中国地方病学杂志

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.

Expression of calcineurin and nuclear factor of activated T cells 1 in testis of rats with chronic fluorosis / 中华预防医学杂志

<p><b>OBJECTIVE</b>To discuss the significance of calcineurin (CaN) and nuclear factor of active T cells 1 (NFATc1) in the damage mechanism of the testis of rats with chronic fluorosis.</p><p><b>METHODS</b>Eighteen clear class SD male rats, aging 6 week-old, were randomly divided into 3 groups, 6 rats in each. The rats of control group were fed with tap water (NaF < 1 mg/L) and the experimental rats were exposed to NaF (lower group: 5 mg/L, higher group: 50 mg/L) to established the chronic fluorosis model. After 8 months, we observed the occurrence of dental fluorosis among rats in different groups, and the contents of urine fluoride were detected by fluorine ion selective electrode method. The body of the rats were weighted as well as their testis. The testis tissues were stained with hematoxylin-eosin and observed under light microscope to find the morphological changes. The expression of CaN and NFATc1's protein and mRNA in testis were detected by Immunocytochemistry (IHC) and In-situ hybridization (ISH).</p><p><b>RESULTS</b>The number of rats which was found dental fluorosis were separately 0, 4 and 5 in control group, low dose group and high dose group (χ(2) = 10.60, P < 0.05). The contents of urine fluoride were gradually increased in control group, low group and high group, which were (1.26 ± 0.17), (2.06 ± 0.64) and (7.69 ± 1.96)mg/L, respectively (F = 36.57, P < 0.05). The body weight were significantly different in all three groups(629.00 ± 16.00), (585.17 ± 17.27), (560.50 ± 16.07)g, F = 26.67, P < 0.05) and the testis weight were without statistical difference ((2.58 ± 0.17), (2.43 ± 0.31), (2.35 ± 0.38)g, F = 0.91, P > 0.05). Compared with the control group, the testicular structures were damaged in the experimental groups and especially significant in high dose group. The expression of CaN (59.10 ± 5.62, 77.93 ± 4.16, 101.69 ± 6.31, F = 74.18, P < 0.05) and NFATc1's (76.11 ± 4.41, 93.42 ± 3.85, 120.42 ± 9.31, F = 92.4, P < 0.05) protein in testis tissues were increased by the fluorine concentration. The mRNA expression of CaN and NFATc1 were separately (CaN: 58.76 ± 7.70, 82.01 ± 6.88, 99.47 ± 8.33, F = 42.65, P < 0.05 and NFATc1: 59.39 ± 4.74, 90.02 ± 5.37, 121.15 ± 7.69, F = 155.47, P < 0.05). There were positive correlation between the expression of CaN and NFATc1's protein and mRNA expression (r = 0.899, r = 0.908).</p><p><b>CONCLUSION</b>The changes in the signaling pathway of expression of CaN may be involved in the injury mechanism of testis tissues of rats with chronic fluorosis.</p>

Influence of chronic fluorosis on the expression of mitochondrial fission protein dynamin-related 1 in the cortical neurons of rats / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the changes of protein expression of mitochondrial fission gene dynamin-related 1(Drp 1) in the cortical neurons of rats with chronic fluorosis.</p><p><b>METHODS</b>A total of 120 one-month-old SD rats (each weighing approximately 100-120 g at the beginning of the experiment) were randomly divided into three groups, and fed with the different doses of fluoride containing in drinking water (untreated control containing 0 mg/L fluoride, and low-fluoride & high-fluoride supplemented with 10 and 50 mg/L fluoride,respectively). After 3 or 6 months exposure, 20 rats from each group were killed. Then the protein expression of mitochondrial fission gene, Drp1, was detected by immunohistochemistry and western-blotting method.</p><p><b>RESULTS</b>Dental fluorosis and urinary fluorosis were obviously found in the rats exposed to fluoride. At the experiment period of 3 months, the numbers of positive cells of Drp1 detected by immunohistochemistry changed. Compared with the control group (36.3 ± 5.8), the changes in low-fluoride group (34.7 ± 4.1) showed no significant difference (t = 1.5, P > 0.05),but the increase in high-fluoride group (45.0 ± 4.7) had statistical significance (t = 8.8, P < 0.05). The western-blotting method had consistent results. Compared with the control group (0.59 ± 0.03), a significant increase of the average topical density in low- fluoride (0.62 ± 0.03) and high-fluoride (0.71 ± 0.02) groups were found (t = 0.02,0.11, P < 0.05). At the experiment period of 6 months, the numbers of positive cells of Drp1 detected by immunohistochemistry significantly changed. Compared with the control group (33.2 ± 4.4), the number in low- fluoride and high-fluoride groups were separately (36.6 ± 3.8) and (39.4 ± 4.2),both increased significantly (t = 3.5,6.3, P < 0.05). Same results could be found in western-blotting method,compared with the control group (0.65 ± 0.06), the average topical density in low- fluoride (0.80 ± 0.09) and high-fluoride (0.76 ± 0.08) groups both increased significantly (t = 0.1,0.1, P < 0.05).</p><p><b>CONCLUSIONS</b>Taking excessive amount of fluoride might result in the changes of expression of Drp1, and the neurons damage from the chronic fluorosis might be associated with the hyperfunction of mitochondrial fusion.</p>

Changed expression of mito-fusion 1 and mitochondrial fragmentation in the cortical neurons of rats with chronic fluorosis / 中华预防医学杂志

<p><b>OBJECTIVE</b>To 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.</p><p><b>METHODS</b>SD 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.</p><p><b>RESULTS</b>Dental 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).</p><p><b>CONCLUSIONS</b>Taking 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.</p>

Relationship of nuclear factor kappa B-related gene expression and osteoclast apoptosis induced by fluoride in bone tissue / 中国地方病学杂志

Objective To investigate the relationship between change of relevant gene of nuclear factor kappa B(NF-κB) and osteoclast apoptosis in bone injury of rats with chronic fluorosis,and to reveal the mechanism of skeletal fluorosis.Methods Thirty-six healthy SD rats,weighting 100-120 g,were randomly divided into three groups(twelve in each group).Rats of control group were fed with tap water(NaF ＜ 1 mg/L) and the experimental rats were exposed to NaF(low-dose group:5 mg/L,high-dose group:50 mg/L) through drinking water to established chronic fluorosis model.All rats were killed at the eight month and metaphysic of femoral was collected.Bone tissues were stained with hematoxylin-eosin and observed under optical microscope.Serum content of tartrateresistant acid phosphatase 5b (TRACP 5b) was detected by enzyme-linked immunosorbent assay (ELISA).Osteoclast was identified and counted by tartrate-resistant acid phosphatase staining(TRAP).The expression of p50,IκBα,Bcl-2 and Bax's mRNA and protein of bone tissue was detected by Real-time PCR and immunohistochemistry.Results Bone sclerosis was observed under optical microscope.The content of TRACP 5b in serum and the number of osteoclast in the low fluoride group[(3.45 ± 1.85)U/L,(6.75 ± 1.29)/slice]were significantly higher than that of the control[(1.26 ± 0.23)U/L,(3.92 ± 1.38)/slice,all P ＜ 0.05],but that of the high fluoride group [(2.74 ± 1.85)U/L,(3.33 ± 1.07)/slice]were lower than that of the low dose group(all P ＜ 0.05).The mRNA expressions of p50,IκBα,Bcl-2 and Bax in low fluoride group(4.41 ± 0.44,1.15 ± 0.25,2.02 ± 0.11,1.25 ± 0.22) were significantly higher than that of the control(1.46 ± 0.10,0.26 ± 0.07,1.00 ± 0.06,0.74 ± 0.09,all P ＜ 0.05),but the high fluoride groups' (0.69 ± 0.09,0.14 ± 0.03,0.95 ± 0.08,0.62 ± 0.08) were lower than that of the low dose group(all P ＜ 0.05).The protein expressions of p50 and IκBα in the low fluoride group (152.96 ± 7.87,156.20 ± 9.75) were significantly higher than that of the control(125.63 ± 9.85,118.97 ± 6.94,all P ＜ 0.05),but the high fluoride group(120.56 ± 9.57,114.50 ± 7.61) were lower than the low dose group(all P ＜ 0.05).The protein expressions of Bcl-2 and Bax(170.61 ± 6.60,160.77 ± 7.66) and the ratio of Bcl-2/Bax (1.07 ± 0.08) were higher than the control(l10.73 ± 5.27,114.64 ± 5.83,0.96 ± 0.04,all P＜ 0.05),but the high fluoride group(81.70 ± 8.00,99.93 ± 3.83,0.81 ± 0.08) were lower than that of the control and the low dose group (all P ＜ 0.05).There was a significant positive correlation between protein expression of p50,IκBα and Bcl-2/Bax (r =0.587,0.676,all P ＜ 0.05).Conclusions Chronic fluorosis can cause change of the relevant gene of NF-κB in rat bone tissues and osteoclast apoptosis.The mechanism of skeletal fluorosis might be related to the abnormal of osteclast apoptosis caused by changes of NF-κB p50 and IκBα.

Expression of nuclear factor kappa B-related mRNA and protein in bone tissue of fluorosis rats / 中国地方病学杂志

ObjectiveTo investigate the expression of nuclear factor kappa B(NF-kB)-related mRNA and protein in bone tissue of rats with chronic fluorosis.MethodsThirty-six healthy SD rats,weighting 100 - 120 g,were randomly divided into three groups (twelve in each group ).Rats of control group were fed with tap water (NaF ＜ 1 mg/L) and the experimental rats were exposed to NaF(low-dose group:5 mg/L,high-dose group:50mg/L) through drinking water.All rats were killed at the eight month and metaphysic of femoral was collected.Bone tissues were stained with hematoxylin-eosin and observed under optical microscope.Bone fluorine was detected by ashing-fluorin ion selective electrode method.Serum content of tartrate-resistant acid phosphatase 5b(TRACP 5b)was detected by enzyme-linked immunosorbent assay(ELISA).The expressions of p50,p65 and IkBα's mRNA and protein in bone tissue was detected by real-time PCR and immunohistochemistry.ResultsBone sclerosis was observed under optical microscope.The contents of bone fluorine in both the low and high doses fluoride groups [(6.32 ± 1.23),( 10.89 ± 1.56) mg/kg] were significantly higher than that of the control [(3.06 ± 1.01 ) mg/kg,all P ＜ 0.05],and of that the high fluoride group was significantly higher than that of the low fluoride group(P ＜ 0.05).Serum content of TRACP 5b of the low fluoride group[(3.45 ± 1.85)U/L] was significantly higher than that of the control[(1.26 ± 0.23)U/L,P ＜ 0.05],but that of the high fluoride group[(2.74 ± 1.85)U/L] was lower than that of the low dose group(P ＜ 0.05).The mRNA expressions of p50 and IkBα in the low fluoride group(4.41 ± 0.44,1.15 ± 0.25) were significantly higher than that of the control(1.46 ± 0.10,0.26 ± 0.07,all P ＜ 0.05),but that of the high fluoride group(0.69 ± 0.09,0.14 ± 0.03) was lower than that of the low dose group(all P ＜ 0.05).The protein expressions of p50 and IkBα in the low fluoride group(152.96 ± 7.87,156.20 ± 9.75) were significantly higher than that of the control( 125.63 ± 9.85,118.97 ± 6.94,all P ＜ 0.05),but the high fluoride groups' ( 120.56 ±9.57,114.50 ± 7.61 ) was significantly lower than that of the low dose group(all P ＜ 0.05).ConclusionFluoride can lead to altered gene expression of NF-kB pathway,and the latter may be involved in fluoride induced bone damage.

Changed transcription level of mitochondrial fission and fusion gene loci in cortical neurons of rats with chronic fluorosis / 中国地方病学杂志

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.

Alteration of mitochondrial distribution and gene expression of fission 1 protein in cortical neurons of rats with chronic fluorosis / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the changes of mitochondrial distribution in axon/soma and the expression of mitochondrial fission 1 (Fis1) protein in the cortical neurons of rats with chronic fluorosis.</p><p><b>METHODS</b>Sixty SD rats were divided into 3 groups (20 each) according to weight hierarchy and fed with different concentrations of fluoride in drinking water (0, 10 and 50 mg/L, respectively) for 6 months. Images of mitochondria and tubulin labeled by immunofluorescence COXIV and tubulin-α were captured with fluorescence microscope. Fis1 protein expression in cortical neurons was analyzed with immunohistochemistry and Western blot. The expression of Fis1 mRNA was detected with real-time PCR.</p><p><b>RESULTS</b>Varying degrees of dental fluorosis and increased fluoride contents in urine were observed in the rats receiving additional fluoride in drinking water. In the cortical neurons of rats fed with 10 mg/L and 50 mg/L fluoride, the numbers of neuronal soma stained with COXIV(34.8 ± 4.7 and 39.3 ± 3.0, respectively), and the expression of Fis1 protein (immunohistochemistry: 54.0 ± 3.6 and 51.3 ± 4.1, respectively; Western blot: 2.9 ± 0.4 and 2.6 ± 0.6, respectively) and mRNA (3773 ± 1292 and 1274 ± 162, respectively) was markedly increased as compared with controls (4.4 ± 2.3, 25.2 ± 2.5, 1.8 ± 0.2 and 277 ± 73) over the experimental period of 6 months.</p><p><b>CONCLUSIONS</b>Excessive intake of fluoride results in an altered mitochondrial distribution in axon and soma in cortical neurons (i.e., the increase in soma and the decrease in axon), increased expression of Fis1 gene and enhanced mitochondrial fission. The altered mitochondrial distribution may be related to the high expression level of Fis1 and a functional disorder of mitochondria.</p>

Expression of mRNA and protein of p38, Osx, PI3K and Akt1 in rat bone with chronic fluorosis / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the expressions of mRNA and protein of p38, Osx, PI3K, Akt1 in the rats bone with chronic fluorosis.</p><p><b>METHODS</b>Dental 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.</p><p><b>RESULTS</b>The 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.</p><p><b>CONCLUSIONS</b>The 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.</p>

Effect of fluoride on oxidative stress and Mn-SOD expression in rats with endemic fluorosis of coal burning / 中华病理学杂志

<p><b>OBJECTIVE</b>To 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.</p><p><b>METHODS</b>SD 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.</p><p><b>RESULTS</b>The 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).</p><p><b>CONCLUSIONS</b>Fluorosis 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.</p>

Effect of fluoride on expression of CaN mRNA and protein in bone tissue of rats / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the changes of mRNA and protein expression of CaN in the bone of rats with chronic fluorosis, and the mechanism of skeletal fluorosis.</p><p><b>METHODS</b>Thirty-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.</p><p><b>RESULTS</b>The 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).</p><p><b>CONCLUSIONS</b>BGP 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.</p>

Effect of fluoride on expression of phosphoinositide 3-kinase, protein kinase B1 mRNA and protein in bone tissue of rats / 中国地方病学杂志

Objective To observe the expression of phosphoinositide 3-kinase(PI3K) and protein kinase B1 (Akt1) in PI3K/Akt signaling pathway in rat bones with fluorosis, and to reveal the mechanisms of the skeletal fluorosis. Methods Thirty-six SD rats were randomly divided into 3 groups (control group, low-dose fluorosis group, high-dose fluorosis group) and 12 rats were in each group according to body weight. 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 groups were fed with water containing NaF 5.0,50.0 mg/L, respectively. Rats were sacrificed after 6 months of treating with fluoride and the serum was kept for testing the bone metabolic markers of none gla protein(BGP) and cathepsin K(Cath-K) by enzyme-linked immunosorbent assay(ELISA), the proteins and mRNA levels of PI3K and Akt1 in rat bones were detected by immunohistochemistry and real time PCR, respectively. Results Each group of serum BGP and Cath-k were compared, the difference was statistically significant(F = 73.45,39.36, all P < 0.05). The contents of BGP[(1.99 ± 0.62), (2.38 ± 0.16)μg/L] and Cath-K [(89.07 ± 19.66), (110.16 ± 9.81)pmol/L] in the low-and high-dose fluorosis groups were higher than those in the control group[(0.15 ± 0.03)μg/L,( 18.32 ± 2.27)pmol/L], and the high fluorosis group was obviously higher than the low fluorosis group (all P < 0.05). Each group of serum PI3K and Akt1 protein and mRNA were compared, the difference was statistically significant(F- 178.16,118.08,38.81,52.31, all P< 0.05). Compared to the control group (181.55 ± 4.24,188.46 ± 2.18,3.84 ± 1.69,4.33 ± 0.89), the protein and mRNA expressions of PI3K(171.66 ± 2.85,154.12 ± 4.15,11.31 ± 4.18,20.54 ± 6.68), Akt1(177.47 ± 3.16,156.42 ± 3.18,12.52 ± 3.13,19.43 ± 5.36) were higher in the low- and high-dose fluorosis groups (all P < 0.05), and the high fluorosis group was obviously higher than the low fluorosis group (all P < 0.05). Conclusions BGP and Cath-K contents could be used as bone metabolic indices in the endemic fluorosis disease. Fluoride can increase the expression of PI3K and Akt1 mRNA and protein in bone tissue of fluorosis rats, and PI3K/Akt1 signaling pathway may be involved in the pathogenesis of bone injury caused by fluoride.

Changes of reactive oxygen species level and mitochondria fission-fusion hi cortical neurons of rats with chronic fluorosis / 中国地方病学杂志

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.

Influence of chronic fluorosis on expression of phospho-Elk-1 in rat brains / 中国地方病学杂志

Objective To investigate the expression and distribution of the downstream substrate of extracellular regulated protein kinase(ERK1/2) pathway, ternary complex factor phospho-Elk-1, in rat brains with chronic fluorosis, and reveal the mechanism of the impaired learning and memory ability caused by chronic fluorosis. Methods Seventy-two SD rats, weighing 100 - 120 g, were randomly divided into 3 groups, 24 in each group (half male and half female). The rats in control group were fed with tap water (fluoride < 0.5 mg/L); low- and high-dose fluoride groups were fed with tap water with different concentrations of NaF(5.0,50.0 mg/L F-, respectively). After 6 months, body weight was weighed, dental fluorosis was determined by observation and urinary fluoride and bone fluoride were detected by fluorine ion-selective electrode; the learning ability of rats was measured by navigation test of Morris water maze, and memory ability by spatial probe test in Morris water maze; the expression and distribution of phospho-Elk-1 in different brain regions were detected by immunohistochemistry method. Results In low- and high-fluoride groups, the body weight of rat[(449.2 ± 77.1), (312.8 ± 89.7)g] was significantly decreased than that of control [(635.5 ± 76.2 )g, all P< 0.05], the varying degrees of dental fluorosis were observed(x2 = 7.83, P<0.05), urinary fluoride[(2.56 ±0.91),(5.73 ±3.14)mg/L] and bone fluoride[(709.2 ± 37.4) ,(1306.3 ± 102.4) mg/kg] were significantly higher than those in controls[(0.92 ± 0.30)mg/L,(348.5 ± 89.2)mg/kg, all P< 0.05]. The escape latency of low- and high-fluoride groups[ (7.4 ± 4.1), (12.2 ± 5.7)s] was longer than that of control [(4.8 ± 2.7 )s, all P < 0.05] and the escape latency in high-fluoride group was significantly longer than that in other groups (all P < 0.05); in spatial probe test, the time of first crossing platform was longer in rats with fluorosis [(4.18 ± 1.10),(5.89 ± 0.56)s] as compared to control[(1.17 ± 0.75)s, all P< 0.05]. Expressions of phospho-Elk-1 in the hippocampus CA1(167.4 ± 8.3,163.2 ± 9.4), CA2(175.7 ± 5.0,183.3 ± 4.2), CA3(165.2 ± 11.6,162.9 ± 4.4), CA4(168.7± 6.9,169.5 ±5.3), fascia dentate (185.2 ±4.0,193.1 ±6.1) and caudate putamen( 181.4 ± 3.8, 179.8 ± 5.5) in low- and high-fluoride groups were higher than those of controls(142.4 ± 8.1,144.9 ± 8.4,143.6 ± 5.8, 116.8 ± 9.1,140.2 ± 7.8,163.1 ± 13.1, all P< 0.05). Conclusion Chronic fluorosis can cause increased expression of phospho-Elk-1 in the hippocampus and caudate putamen region of rat brains, which might be related to the mechanisms of decreased learning and memory ability of rats overexposed to fluoride.

Effect of endemic fluoride poisoning caused by coal burning on the oxidative stress in rat testis / 中国医学科学院学报

<p><b>OBJECTIVE</b>To explore the effect of endemic fluoride poisoning caused by coal burning on the oxidative stress in rat testis.</p><p><b>METHODS</b>Totally 40 male SD rats were equally randomized into four groups control group, low fluorosis group, middle fluorosis group, and high fluorosis group. Rats in all three fluorosis groups were fed with corn dried by burning coal obtained from endemic fluorosis areas with high fluoride, and thus the animal models of fluorosis were established. After 120 and 180 days, all the rats were sacrificed. Testis tissues were stained with hematoxylin eosin and observed under light microscope. The malonaldehyde (MDA) content, superoxide dismutase (SOD) activity, total nitric oxide synthase (TNOS), and inducible nitric oxidase synthase (iNOS) were measured by biochemical methods in the testis tissues. The content of NaF in testis was measured by fluorine selective electrode.</p><p><b>RESULTS</b>The rat fluorosis models were successfully established. The fluoride content in testis was significantly increased in all the fluorosis groups(P<0.01). Testicular structures were damaged in all of fluoride groups. The TNOS, iNOS activities, and MDA content of each fluoride group were significantly higher than that of the control group on day 120 and 180 (P<0.05 or 0.01 ). The TNOS, iNOS activities, and MDA content significantly increased in a dose dependent manner (P<0.05 or 0.01). The SOD activities significantly decreased in all the fluoride groups (P<0.05 or 0.01).</p><p><b>CONCLUSIONS</b>Endemic fluoride poisoning caused by coal burning can cause disorders in the oxidative system and antioxidative system in rat testis. The oxidative stress may play an important role in the fluorides induced reproductive toxicity in male rats.</p>

Inhibition of polylysine-EDTA on rabbit lens epithelial cell growth in vitro / 中华实验眼科杂志

BackgroundPosterior capsule opacification(PCO) is the main cause inducing low vision after extacapsular cataract extraction. Our previous study determined that polylysine-ethylene diamine tetraacetic acid (EDTA) (PLE) can suppress the incidence of PCO. ObjectiveThe goal of this experiment was to investigate the inhibition of polylysine-EDTA on rabbit lens epithelial cells (LECs)proliferation in vitro and the effective concentrations of polylysine-EDTA. MethodsThe anterior capsular membranes from 10 3-month-old clean New Zealand white rabbits were digested and then cultured to obtain the LECs. The second and third generation of LECs were inoculated on the 96-hole culture plate with the cell density of the 1 × 105/ml. 12.5,25.0,50. 0,100. 0 μmol/Lof PLE were added into the culture medium for 48 hours respectively,and the DMSO medium was used at the same way as the control group. The proliferation of the LECs was then detected by MTT method and the inhibitory rate of PLE on LECs growth was calculated. ResultsLECs grew at a near normal state in ≤25.0 μmol/L PLE groups,however,cultured LECs were out of shape and the numbers decreased with the weakened adhesion ability in ≥50.0 μ mol/L PLE groups. The A490 values of LECs were 0. 278±0. 013,0. 266±0. 028,0. 260±0. 022 and 0. 247±0. 012 in 12. 5,25.0,50. 0, 100. 0 μmol/L polylysine-EDTA groups respectively and were lower than 0. 311 ±0. 038 of DMSO control group( P=0. 035,0. 011,0. 009,0.013 ). The inhibitory rates of 12. 5,25.0,50. 0, 100.0 μmoL/L PLE on LECs proliferation were 10.61％ , 14.47％ , 16.40％ and 20. 58％ respectively. ConclusionsPolylysine-EDTA can inhibit the growth and proliferation of LECs in vitro at a dose-dependent manner.

Expression of osteopontin in renal tissue of rats with endemic fluorosis caused by exposure to coal burning and with low calcium / 中国地方病学杂志

Objective To detect the osteopontin(OPN)expression in renal tissue of rats with fluorosis and low calcium diet,and study the role of OPN in renal injury of fluorosis.Methods Forty-eight aged 1 month Wistar rats,80-120 g,were randomly divided into 4 groups by 2×2 factorial design(the number of female and male in each group was equal):the control group,high-flluoride group,low-calcium group and low-calcium with high-fluoride group.All rats of the fluorosis groups were fed with feed containing corn exposed to coal-burning from endemic fluorosis areas with high fluoride(100 mg/kg,corn),the other two groups were fed with feed containing coru from nonendemic fluorosis areas(fluoride 5 mg/kg,corn).After 16 weeks,the rats were killed.The change of teeth was examined,and the incidence rate of dental fluorosis was calculated.The expressions of both protein and mRNA of OPN in rat renal tissue were determined by RT-PCR and immunohistochemistry after four-month experimentation.Results The growth of teeth was very well in the control group and the low-calcium group.The two high-fluoride groups showed evident dental fluorosis(100%).The results of immunohistochemistry showed that the OPN protein was localized in renal tubule cytoplasm.The OPN-positive cells from renal tissue were lightly and scatteredly stained in control and low-calcium groups.The OPN-positive cells had deeper color in high-fluoride group and low-calcium with high-fluoride group,widely distributed in the renal tubular epithelial cells.The protein expression of OPN in the two groups exposed to fluoride(168.64±13.21,169.26±8.92)was significantly higher than those of the corresponding control group(145.78±10.26,all P<0.01)and low-calcium group(149.60±16.84,all P<0.01).The mRNA expression of OPN in the two groups exposed to fluoride(1.89±0.37,1.94±0.22)was significantly higher than those of the corresponding control group(1.32±0.26,all P<0.05)and low-calcium group(1.30±0.186,P<0.05),respectively.High fluoride influenced the expression of protein and mRNA of OPN(F=13.821,4.24,all P<0.05).Low calcium did not affect the expression of protein and mRNA of OPN(F=2.164,0.58,all P>0.05).However,high fluoride and low calcium had a cross interaction on the expression of protein and mRNA of OPN(F=6.257,432,all P<0.05).Conclusions Over-dose fluoride enhances the expression of OPN.The higher expression observed in the cases exposed to high fluoride concentration is associated with serious renal injury.OPN may he a potential marker for renal injury in fluorosis.Moreover,over-dose fluoride and low calcium make the renal injury worse,indicating low calcium plays an important part in renal injury by fluoride.

Expression of PURA gene and its protein in nephridial tissue of rats with fluorosis of coal-burning / 中国地方病学杂志

Objective To investigate the meaning of PURA gene and its protein in nephridial tissue of the rats with endemic fluorosis of coal burning. Methods Thirty-six SD rats of 80 - 100 g, body weight were randomly divided into control group, low fluorosis group and high fluorosis group according to body weight, 12 in each group, the number of female and male in each group was the same respectively. The control group, Low fluorosis group and high fluorosis group rots were fed with 1.5,25.0,60.0 mg/kg fluoride content in feedstuff, to establish the animal model of fluorosis. Expressions of both mRNA and its protein of PURA gene in rat nephridium tissue, were determined by RT-PCR and immunohistochemistry after four-month experimental period. Results The expressions of PURA mRNA[(2.74± 1.06),(4.29 ± 2.11)] and its protein[ (28 827.91 ± 4801.94),(61 146.96 ± 4997.55)] in low fluorosis group and high fluorosis group was higher than that in the control group[ ( 1.13 ± 0.87), (7131.95 ± 1524.54), all P < 0.05]. And the expressions of PURA mRNA and protein in high fluorosis groups was higher than that in low fluorosis greup(all P < 0.05). Conclusion High fluoride can lead to the high expression of PURA gene mRNA and protein in the rat nephridium tissue exposed to sodium fluoride.