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Objective To observe the level of reduced glutathione(GSH) and oxidized glutathione(GSSG)in a mouse bone cell line MC3T3-E1 cells exposed to fluoride.Methods MTT method was used to detect cell viability of M C3T3-E1 cells exposed to varying concentrations and periods of fluoride [F-concentration:0(control),0.5,1.0,2.0,4.0,8.0,12.0,20.0 mg/L; F-periods:1,2,4 and 10 days].The Xevo TQ MS was employed to test the levels of GSH,GSSG and glutamine (Gln).Results The MC3T3-E1 cell viability was significantly higher in the 2 mg/L group(0.57 ± 0.05) 1 day after the exposure compared to the respective control(0.49 ± 0.03,P ＜0.01); conversely,cell viability was markedly lower in the 8 mg/L(0.49 ± 0.07) and 12 mg/L(0.47 ± 0.09)groups 4 days after the exposure in comparison to the control(0.63 ± 0.06,P ＜ 0.05 or P ＜ 0.01).The cell viability in the 8 mg/L group(1.52 ± 0.29) 10 days after the exposure was significantly higher than that in the control group (0.86 ± 0.23,P ＜ 0.01),however,the value in the 20.0 mg/L group (0.54 ± 0.07) was significantly lower(P ＜0.01).The level of cell GSH decreased significantly in the 20 mg/L groups 2 days[(13.92 ± 4.63)μmol/L]and 10 days [(0.53 ± 0.30)μmol/L]after exposure compared to the respective comtrols [(26.42 ± 3.67),(24.85 ± 5.68)μmol/L,all P ＜ 0.01].The level of cell GSSG markedly increased in the 2 mg/L group 2 days [(1.12 ± 0.62)μ mol/L]and the 8 mg/L group 4 days [(2.13 ± 0.62)μ mol/L]after exposure compared to the controls[(0.55 ± 0.22),(1.46 ± 0.46)μmol/L,all P ＜ 0.05].The similar change was observed in the 8 mg/L group[(2.97 ± 1.30)μmol/L] 10 days after exposure compared to the control [(1.35 ± 0.50)μmol/L,P ＜ 0.05].The level of Glndecreased significantly in the 2 mg/L group[ (62.80 ± 17.4l)μ mol/L] 4 days and in the 8 and 20 mg/L groups 10 days[ (122.26 ± 19.51), (19.38 ± 8.11)μmol/L] after exposure compared to the controls [ (83.28 ±14.32), ( 147.15± 16.95) μmol/L , all P ＜ 0.05 or P ＜ 0.01 ]. Conclusions Fluoride exposure can significantly promote the changes of GSH, GSSG and Gln levels in the osteoblast, thus affecting the intracellular redox equilibrium.
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Objective To observe the protein and gene expression of immunoglobulin binding protein (BiP) in the femur of fluoride-treated rats, and preliminarily study the possible role of endoplasmic reticulum stress in the pathogenesis of skeletal fluorosis. Methods Sixty Wistar rats were divided into 4 groups according to body weight, n =15. The control and low-calcium groups were fed with normal diet(0.79％ calcium) and low-calcium diet(0.063％ calcium), respectively, and both drank tap water(fluoride concentrations ＜ 1 mg/L). High-fluoride and coexpesure to low-calcium groups were fed with conventional feed (0.79％ calcium) and low-calcium diet (0.063％ calcium), respectively, and both drank tap water containing sodium fluoride (sodium fluoride concentration of 221 mg/L). During experimental period, rats were measured body weight once a week with a stand diet and water available ad libitum. The experiment lasted for 12 weeks. The immunohistochemical and reverse transcription polymerase chain reaction(RT-PCR) techniques were used to detect the protein and gene expression of BiP in the femur of fluoride-treated rats and control subjects. Results The bone mineral contents of high fluoride, lowcalcium and coexposure groups[(0.131 ± 0019), (0.097 ± 0.011 ), (0.083 ± 0.007)g/cm] were lower than those of the control group[(0.159 ± 0.029)g/cm, all P ＜ 0.05]; the bone mineral density of low calcium and coexpesure to fluoride group[(0.243 ± 0.018), (0.223 ± 0.022)g/cm2] was lower than that of the control group[(0.296 ± 0.046)g/cm2, all P ＜ 0.05]. The immunohistochemical staining showed that the anti-BiP antibody positive osteoblasts were significantly increased in the low calcium diet and coexposure to fluoride groups than that in the control, and coexposure to fluoride elevated the positive cells than that in only low calcium diet group. The mRNA expression of osteopontin(OPN) and osteocalcin(OCN) in coexposure to fluoride with low-calcium group(1.36 ± 0.20, 1.31 ±0.11 ) was higher than that of the control groups (0.82 ± 0.16, 0.85 ± 0.15, all P ＜ 0.05) ; moreover, OPN expression significantly increased in this group than that of the only high fluoride group (0.97 ± 0.29, P ＜ 0.05). The mRNA expression of BiP in the low calcium and coposure to fluoride group (1.38 ± 0.24,1.35 ± 0.12) was significantly higher than that of the control group ( 1.14 ± 0.06, all P ＜ 0.05 ). Conclusions Higher fluoride or coexposure to low calcium diet stimulates the gene and protein expression in rat femur BiP, indicating that varying degrees of endoplasmic reticulum stress is likely involved in the pathogenesis of rat skeletal fluorosis.
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Objective To observe the expression of vascular endothelial growth factor(VEGF) mRNA and protein in fluoride(F~-) treated fibroblast(FB) of mice in planar(2D) and FBs populated collagen lattice(3D) culture systems and to further explore the effects of VEGF on the osteogenic action of FB. Methods FB were divided into 0 (control group), 0.0001,0.0010,0.1000,1.0000,10.0000 and 20.0000 mg/L groups(F~-). The levels of VEGF mRNA and protein at 48 h were measured by using RT-PCR, ELISA and immunohistochemistry (IHC) methods. Results The expression of VEGF mRNA increased obviously in group of 0.1000 mg/L(1.08 ± 0.09) in 3D FB compared with the control group(0.93 ± 0.02, all P < 0.05). Fluoride increased the content of VEGF protein obviously in groups of 0.1000,1.0000,10.0000 mg/L(0.19 ± 0.02, 0.26 ± 0.01 and 0.32 ± 0.01 ), higher than that in 2D FB culture supematant in the control group(0.14 ± 0.01, all P < 0.05) ; and in groups of 0.1000, 1.0000 rag/L(0.59 ± 0.06 and 0.52 ± 0.03) it was higher than that in 3D FB culture supematant in the control group(0.37 ± 0.05, all P< 0.01 ). The IHC results showed that the VEGF positive staining cells increased significantly in group of 0.001 mg/L (0.45 ± 0.05) in 2D FB when it was compared with control group(0.36 ± 0.03, P< 0.05); and in groups of 0.0010, 0.1000, 1.0000 rag/L(0.62 ± 0.04,0.70 ± 0.06 and 0.65 ± 0.07) are it was higher than that in 3D FB control group (0.44 ± 0.04, P < 0.05 or < 0.01 ). Conclusions The higher expression of VEGF mRNA and protein in 2D and 3D FB induced by fluoride may play an important role in stimulating the osteogenesis ability in FB.
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Objective To observe endoplagmic reticulum stress in bone tissue of fluomsis rats and further explore the pathogenesis of skeletal fluorosis.Methods 48 Wistar rats were divided into 4 groups according to their body mass.The control and low.calcium group were fed with normal diet(0.79%calcium)and low-calcium diet(0.79%calcium)respectively,and both drank tap water(sodium fluoride concentrations＜1 mg/L).High fluoride and low.calcium plus high-fluoride groups were fed with normal diet(0.79%calcium)and low-calcium diet (0.79%calcium)respectively,and both drank tap water containing sodium fluoride(sodium fluoride concentrations 221 mg/L).During experimental period,rats were measured body mass once a week with a stand diet and water available ad libiturn.The experimental period was 3 months.The biochemical techniques were used to test the indicators of oxidative stress and ALP in seFum of fluorosis rats.The total RNA was extracted from the one side of the femur,and the transcription level of Bip,Xbp1,CHOP and PDI were investigated by reverse transcription polymerase chain reaction(RT-PCR).Results The level of MDA in serum of low-calcium plus high-fluoride group wag higher than that of the control[(14.74±3.11)μmol/L vs(10.15±1.96)μmol/L,P＜0.05];the activity of GPx was ma~edly higher in hish-fluoride group compared with the control[(3.87±0.41)×103 U/L vs(2.85± 0.55)×103 U/L,P＜0.05];the level of uric acid in sel'um was significantly lower both in high-fluoride group and low-calcium plus high-fluoride group compared with the respective control and the low-calcium group[(73.95± 9.52)μmol/L vs(110.43±25.48)μmol/L,(54.32±22.09)μmol/L vs(101.71±17.01)μmol/L,P＜0.05]. The activity of ALP wag obviously higher in low-calcium plus high-fluoride group compared with the control [(24.77±4.57)×103U/L vs (12.91±3.97)×103U/L,P＜0.01)].The mRNA expression of Bip/GAPDH in bone tissue was markedly higher in bone of high-fluoride group and low-calcium plus high-fluoride group compared with the control(1.38±0.24,1.35±0.12 vs 1.14±0.06,P ＜ 0.05). The expression of Xbp1/GAPDH in bone tissue significantly increased in low-calcium plus high-fluoride groups compared with the control and the low-calcium group (1.48±0.20 vs 1.02±0.25,1.07±0.25,P ＜ 0.05 or ＜ 0.01);and CHOP/GAPDH in bone tissue significantly increased in low-calcium plus high-fluoride groups compared with the control(0.84±0.18 vs 0.52±0.07,P ＜ 0.05 ). Conclusions Accelerated osteogenetic action is seen in fluorosis rats,accompanied by oxidative stress and bone endoplasmic reticulum stress,which is likely involved in the pathogenesis of skeletal fluorosis.
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Objective To study the influence of fluoride on the expression of osteoprotegerin(OPG) mRNA and protein in suckling rat osteoblasts. Methods Osteoblasts obtained from calvarial of suckling Wistar rats were cultured in vitro in the media supplemented with NaF at a series of doses[O(control), 1,2 and 4 mg/L groups], and OPG mRNA expression and protein were evaluated by RT-PCR and ELISA methods, respectively. Results OPG mRNA expression in suckling rat osteoblasts cultured in vitro significantly increased after exposure to NaF for 48 h and 72 h(F=333.48,808.34,P<0.05). OPG mRNA expression in suckling rat osteoblasts cultured in vitro after exposure to NaF for 48 h at different doses(0.810±0.003, 0.819±0.031 and 0.870±0.044 for 1,2 and 4 mg/L groups, respectively) compared with that of control (0.800±0.040, all P<0.05). OPG mRNA expression further increased for 72 h exposure to NaF(0.933±0.047,1.031±0.051,1.240±0.062 for 1,2 and 4 mg/L, respectively), significantly higher than that of the control (0.805±0.020,all P<0.05) and corresponding groups at 48 h. NaF doses and time exposure exhibited a significant synergistic effect on OPG mRNA expression(F=2004.16, P<0.05). NaF also enhanced OPG protein expression in suckling rat osteoblasts cultured in vitro. Significant differences were observed only in 4 mg/L group(0.228±0.014,0.277±0.048) and control(0.205±0.012,0.229±0.010) at 48 h and 72 h (P<0.05). In addition, OPG protein expression at 72 h post-exposure was higher than that at 48 h,but there was no synergistic effect between concentration and time(F=1.21,P>0.05). Conclusions The results suggested that NaF could increase OPG mRNA and protein expression in suckling rat osteoblasts with a synergistic effect between the doses and exposure time.
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<p><b>OBJECTIVE</b>To compare the anti-hypercholesterolemic and cholesterol absorption inhibitory activities between total saponin of Dioscorea panthaica (TSDP) and diosgenin (Dio).</p><p><b>METHOD</b>TSDP and Dio were given ig or i.p. to mice or rats treated with cholesterol feed to evaluate their preventive and therapeutic effect on hypercholesterolemia. TSDP or Dio and cholesterol were mixed with pig bile to form the micelle, then the freeing cholesterol was detected to evaluate inhibitory effect of the both compounds on cholesterol absorption.</p><p><b>RESULT</b>Dio (80 and 160 mg.kg-1) showed significantly therapeutic and preventive effect on hypercholesterolemia in mice, while TSDP showed a certain preventive activity only at a big dose (400 mg.kg-1). The intraperitoneal injection of Dio (20 and 40 mg.kg-1) to mice suffered from hypercholesterolemia was effective, but TSDP showed no effective. The serum total cholesterol level was decreased when rats were pre-treated with TSDP (200 and 400 mg.kg-1, ig) and Dio (200 and 100 mg.kg-1, ig). However, the hypercholesterolemia-preventing activity of Dio was stronger than that of TSDP. In addition, inhibitory effect of Dio on cholesterol micelle formation was still stronger than that of TSDP.</p><p><b>CONCLUSION</b>The preventive and therapeutic activity of Dio against hypercholesterolemia indused by cholesterol in mice or rats is stronger than that of TSDP. The anti-hypercholesterolemia mechanism of Dio is probably related with its cholesterol absorption inhibitory activity.</p>