ABSTRACT Objective: To explore the potential effect of miR-125b on p53-mediated regulation of Bax/Cytochrome C/Caspase-3 apoptotic signaling pathway in rats with cerebral ischemia-reperfusion (CIR) injury. Methods: Sprague-Dawley (SD) rats were used to conduct CIR injury and injected with miR-125b mimic/inhibitor or p53 inhibitor (Pifithrin-α, PFT-α). Dual-luciferase reporter gene assay was used to analyze the targeting relationship between miR-125b and p53. Longa scoring and Triphenyl tetrazolinm chloride (TTC) staining were used to test the neurologic function and determine infarct size, respectively. Hematoxylin-eosin (HE) and Nissl’s stainings were conducted to observe the morphology of cortical neurons. Neuronal nuclei (NeuN) expression was detected by immunohistochemical staining. QRT-PCR was performed to detect the expressions of miR-125b and p53. TUNEL staining and Western blotting was used to determine neuronal apoptosis and expressions of Bax/Cytochrome C/Caspase-3 signaling pathway-related proteins, respectively. Results: Our results showed that miR-125b could directly target p53. As observed, overexpression of miR-125b could obviously reduce the neurological score, infarct size, and brain water content after CIR in rats, which also improved the morphology of cortical neurons, increased the number of neurons, reduced neuronal apoptosis, and inhibited the expressions of Bax/Cytochrome C/Caspase-3 pathway. Moreover,the similar results were observed in rats with CIR after injected with PFT-α. But no significant differences in each index were found in CIR group and CIR + anti-miR-125b + PFT-α group. Conclusion: MiR-125b exerts protective effects on CIR injury through inhibition of Bax/Cytochrome C/Caspase-3signaling pathway via targeting p53, which is likely to be a promising treatment for CIR. Abbreviations: 3’–UTR: 3–untranslated region; CIR: cerebral ischemia–reperfusion; CIS: cerebral ischemic stroke; PFT–α: Pifithrin–α; PVDF: polyvinylidene fluoride; SD: Sprague–Dawley; TBST: tris buffered saline with tween. TTC staining: Triphenyl tetrazolinm chloride staining; TUNEL: Terminal deoxynucleotidyl transferase–mediated dUTP–biotin nick end labeling.

Calcium homeostasis of osteoblasts (OBs) has an important role in the physiology and pathology of bone tissue. In order to study the mechanisms of intracellular calcium homeostasis, MC3T3-E1 cells and Sprague-Dawley rats were treated with different concentrations of fluoride. Then, we examined intracellular-free calcium ion ([Ca2+]i) in MC3T3-E1 cells as well as mRNA and protein levels of Cav1.2, the main subunit of L-type voltage-dependent calcium channels (VDCCs), Na+/Ca2+ exchange carriers (NCS), and plasma membrane Ca2+-ATPase (PMCA), inositol 1,4,5-trisphosphate receptor (IP3R) channels, sarco/endoplasmic reticulum calcium ATPase 2b (SERCA2b)/ATP2A2 in vitro, and rat bone tissues in vivo. Our results showed that [Ca2+]i of fluoride-treated OBs increased in a concentration-dependent manner with an increase in the concentration of fluoride. We also found that the low dose of fluoride led to high expression levels of Cav1.2, NCS-1, and PMCA and low expression levels of IP3R and SERCA2b/ATP2A2, while the high dose of fluoride induced an increase in SERCA2b/ATP2A2 levels and decrease in Cav1.2, PMCA, NCS-1, and IP3R levels. These results demonstrate that calcium channels and calcium pumps of plasma and endoplasmic reticulum (ER) membranes keep intracellular calcium homeostasis by regulating Cav1.2, NCS-1, PMCA, IP3R, and SERCA2b/ATP2A2 expression.

Parathyroid hormone (PTH), PTH-related peptide (PTHrP), and calcium-sensing receptor (CaSR) play important roles in maintaining calcium homeostasis. Here, we study the effect of fluoride on expression of PTH, PTHrP, and CaSR both in vitro and in vivo. MC3T3-E1 cells and Sprague-Dawley rats were treated with different concentrations of fluoride. Then, the free calcium ion concentration in cell culture supernatant and serum were measured by biochemical analyzer. The expression of PTH, PTHrP, and CaSR was analyzed by qRT-PCR and Western blot. We found that the low dose of fluoride increased ionized calcium (i[Ca2+]) and the high dose of fluoride decreased i[Ca2+] in cell culture supernatant. The low dose of fluoride inhibited the PTH and PTHrP expression in MC3T3-E1 cells. The high dose of fluoride improved the PTHrP expression in MC3T3-E1 cells. Interestingly, we found that NaF decreased serum i[Ca2+] in rats. Fluoride increased CaSR expression at both messenger RNA (mRNA) and protein levels in MC3T3-E1 cells and rats. The expression of PTHrP protein was inhibited by fluoride in rats fed regular diet and was increased by fluoride in rats fed low-calcium diet. Fluoride also increased the expression of PTH, NF-kappaB ligand (RANKL), and osteoprotegerin (OPG) in rats. The ratio of RANKL/OPG in rats fed low-calcium food in presence or absence of fluoride was significantly increased. These results indicated that fluoride might be able to affect calcium homeostasis by regulating PTH, PTHrP, and CaSR.

In this paper, 3-aminobenzeneboronic acid functionalized Mn2+-doped ZnTe/ZnSe quantum dots (APBA-dQDs) were prepared. The APBA functional groups had strong binding ability with F–, resulting in the quenchment of dQDs photoluminescence (PL). Under the optimal condition, the fluorescence intensity of APBA-dQDs was related linearly to the concentration of F– in the range of 0.25–1.5µmol/L with a detection limit of 0.1µmol/L. The selectivity of fluorescence quenching of APBA-dQDs for F– was enhanced. Moreover, the proposed methodology for the sensing of F– at EM 560nm in MC3T3-E1 osteoblastic cells was demonstrated and got a satisfactory results. The results indicate that the APBA-dQDs are promising candidates for intracellular in MC3T3-E1 osteoblastic cells. To the best of our knowledge, it was the first report of F– sensing by using the quenched fluorescence of APBA-dQDs in non-cancerous cells.

To study the effects and importance of fluoride on FBs in the development of extraperiosteal calcification and the ossification of skeletal fluorosis, the presence of the osteogenic phenotype, which is indicated by the expression of core-binding factor α1 (Cbfa1) and osteocalcin (OCN), in an FB cell line (L929) and in osteoblasts (OBs) exposed to fluoride was determined. Fibroblasts and osteoblasts were exposed to different concentrations of fluoride (0, 0.0001, 0.001, 0.1, 1.0, 10.0 and 20.0 mg/L F−). By using RT-PCR and ELISA, the mRNA levels of Cbfa1 and OCN were measured at 48 h, and the protein levels of Cbfa1 and OCN were measured at 2, 4, 24, 48 and 72 h. The data demonstrated the following: (1) The Cbfa1 protein level in fluoride-treated fibroblasts clearly increased at 48 h in the groups treated with 0.0001, 0.001, 0.1, 1.0 and 20.0 mg/L F−. The Cbfa1 protein level of the group treated with 10 mg/L F− at 72 h was higher than that of the control group. The level of Cbfa1 mRNA in the fibroblasts was much higher at 48 h in the group treated with 10.0 mg/L F− than in the control group. (2) The OCN protein level in fluoride-treated fibroblasts was significantly higher than that of the control group in the 0.0001, 0.1, 1.0, 10.0 and 20.0 mg/L F− groups at 2 h, and in the 0.001 and 0.1 F− groups at 4 h. A slightly higher level of OCN mRNA in fluoride-treated fibroblasts was also found in the 1.0 and 20.0 mg/L F− groups compared to the control group. (3) The expressions of Cbfa1 and OCN in osteoblasts treated with the same experimental conditions as the fibroblasts were up-regulated by fluoride following the same trend as in the fibroblasts. Our results showed an increase in the expression of Cbfa1 and OCN in fibroblasts and osteoblasts exposed to fluoride and suggested that the osteogenic function of fibroblasts induced by fluoride could play an important role in the development of extraperiosteal ossification during skeletal fluorosis.

Osteoblast L-type voltage-dependent calcium channels (VDCC) play important roles in maintaining intracellular homeostasis and influencing multiple cellular processes. In particular, they contribute to the activities and functions of osteoblasts (OBs). In order to study how L-type VDCC modulate calcium ion (Ca(2+)) homeostasis and the expression of osteogenic transcription factors in OBs exposed to fluoride, MC3T3-E1 cells were exposed to a gradient of concentrations of fluoride (0, 2.0, 5.0, 10.0 mg/L) in combination with 10 μM nifedipine, a specific inhibitor of VDCC, for 48 h. We examined messenger RNA (mRNA) and protein levels of Cav1.2, the main subunit of VDCC, and c-fos, c-jun, runt-related transcription factor 2 (Runx2), osterix (OSX), and intracellular free Ca(2+) ([Ca(2+)]i) concentrations in MC3T3-E1 cells. Our results showed that [Ca(2+)]i levels increased in a dose-dependent manner with increase in concentration of fluoride. Meantime, results indicated that lower concentrations of fluoride (less than 5 mg/L, especially 2 mg/L) can lead to high expression of Cav1.2 and enhance osteogenic function, while high concentration of fluoride (10 mg/L) can induce decreased Cav1.2 and osteogenic transcriptional factors in MC3T3E1 cells exposed to fluoride. However, the levels of [Ca(2+)]i, Cav1.2, c-fos, c-jun, Runx2, and OSX induced by fluoride were significantly altered and even reversed in the presence of nifedipine. These results demonstrate that L-type calcium channels play a crucial role in Ca(2+) homeostasis and they affect the expression of osteogenic transcription factors in fluoride-treated osteoblasts.

Objective To observe the expression of fibronectin in bone of fluorosis rats and in vitro cultured osteoblast,and to study the role of fibronectin in pathogenesis of chronic fluorosis.Methods Male and female Wistar rats 144 were randomly divided into four groups,which were designated as the control group(normal diets,n =36),fluoride group(normal diets + 100 mg/L fluoride,n =36),lower calcium monophagia group (synthetic diets,n =36) and lower calcium monOphagia with fluoride group(synthetic diets + 100 mg/L fluoride,n =36).Rats were sacrificed 4 and 8 months after beginning of the experiment,respectively,and femur tissue was fixated and paraffin-embedded.The osteoblast isolated from calvaria of neonatal rats was treated with different dose of fluoride(0,1,2,4 mg/L fluoride,respectively) for 48 and 72 h,cell culture supernatant and cells were collected,respectively.The cranial osteoblasts were cultured in vitro and divided into four groups according to different concentration of fluoride added,which were 0(control group),0.01,1.00,and 10.00 mg/L groups.These cells were treated with mineralized induced medium at day 2 and cultured for 3 more weeks whereafter,and then the slides were fixed in alcohol.The expression of fibronectin in rat femur tissue was detected by immunohistochemistry (IHC),and fibronectin mRNA expression was determined by in situ hybridization; the fibronectin levels in supernatant of cultured osteoblast was examined by enzyme-linked immunosorbent assay(ELISA),and the expression of fibronectin mRNA in osteoblasts was detected with RT-PCR; skull mineralized nodule formation of osteoblasts was observed under a light microscopy after stained with 0.1％ red alizarin liquid.Results Little expression of fibronectin (brown granules under light microscope) could be seen in femur tissue of fluorosis rats of control group and lower calcium monophagia group; but abundantly expressed in fluoride group and lower calcium monophagia with fluoride group; the fibronectin was also expressed in osteoblasts,bone cells and bone marrow cells with less red particles in the control group and lower calcium monophagia group,but more in the fluoride group and lower calcium monophagia with fluoride group.The expression of fibronectin protein in supernatant of cultured osteoblasts was significantly increased in the group of 4 mg/L fluoride at 48 h(0.108 ± 0.042,t =0.764,P＜ 0.05) compared with control group(0.081 ± 0.010); the value was also significantly increased in 1,2,4 mg/L groups at 72 h(0.089 ± 0.010,0.087 ± 0.012,0.098 ± 0.023; t =0.765,0.704,0.996; all P ＜ 0.05) compared with control group (0.070 ± 0.014) ; the expression of fibronectin mRNA was much higher in 1,2,4 mg/L groups at 48 h (0.61 ±0.06,0.77 ± 0.07,0.77 ± 0.07) and 72 h(1.61 ± 0.14,2.54 ± 0.20,2.75 ± 0.22) compared with control group [0.48 ± 0.04(t =0.111,0.182,0.182,all P ＜ 0.05),0.97 ± 0.08(t =0.093,0.109,0.108,all P＜ 0.05) ].A lot of mineralized nodules could be seen under light microscope in 1.00 and 10.00 mg/L groups.Conclusions The expression of fibronectin in bone of fluorosis rats and in vitro cultured osteoblasts are increased,and fluoride also promotes the mineralization nodules formation of osteoblasts.These results suggest that fibronectin may regulate the process of bone mineralization,and possibly play a role in the development of skeletal fluorosis.

Objective To study the different expressions of receptor activator of nuclear factor-kappa B ligang(RANKL) mRNA in spleens of rats fed with diet of low calcium and high fluoride. Methods A 2× 2×2 factorial design was used and the factors were calcium, fluoride and action time. In the design, 40 Wistar rats [average body mass(118.9±13.5)g] were divided into four groups randomly by weight: control with normal diet (0.790%, calcium), low calcium group with low calcium intake(0.063%, calcium), high fluoride group with normal diet and high fluoride intake(100 mg/L, fluoride) and low calcium and high fluoride group with low calcium and high fluoride intake. After 4 and 8 months, 5 rats of each group were sacrificed and total RNA was extracted from spleen. And the expression levels of RANKL mRNA were determined by reverse transcription polymerase chain reaction (RT-PCR). Results At time of 4 months, the expression level of RANKL mRNA was 0.13± 0.05,0.13± 0.03,0.17±0.02,0.27± 0.05 and at time of 8 months, it was 0.11 ± 0.01,0.16 ± 0.02,0.16± 0.03,0.36 ± 0.07 in control group, low calcium group, high fluoride group, low calcium with high fluoride group, repectively. The factorial design AVONA showed that low calcium and high fluoride had significant effects on RANKL mRNA expression(F = 40.224,56.679, all P < 0.05) while action time had not(F = 2.850, P > 0.05 ). The interactions of low calcium with high fluoride or high fluoride with action time were signifieant(F = 7.247, 18.789, all P < 0.05) while the interaction of high fluoride with action time was not(F = 1.751, P > 0.05). Conclusions Low calcium alone or high fluoride alone or low calcium with high fluoride or low calcium with action time can increase the the RANKL mRNA expression level. High fluoride does not affect the RANKL mRNA level as the action time is prolonged.

Objective To observe the effect of treatment with fluoride at various concentrations for various hours on expressions of insulin-like growth factor-1(IGF-1)in two-dimensional(2D)and three-dimensional(3D)cultures,and investigate its role in stimulation of osteoplastic function of fibroblasts(FBs)with fluoride.Methods The FBs in 2D and 3D culture systems were divided into one control and six test groups separately.The FBs in six test groups were added with DMEM containing 0.000 1,0.001,0.1,1,10 and 20 mg /L of fluorine ion respectively,while those in control groups with DMEM containing no fluorine ion.The IGF-1 protein contents in culture supernatants of FBs in 2D culture system were determined 2,4,24,48 and 72 h,while those in 3D culture system,4,24,48,72 and 96 h after treatment with fluoride by ELISA.Meanwhile,the expressions of IGF-1 in FBs treated with fluoride were determined by immunohistochemical(IHC)method,while the transcription of IGF-1 mRNA by RT-PCR.Results The treatment with fluoride stimulated the expression of IGF-1 protein in culture supernatant of FBs significantly.IHC method showed that the color of IGF-1-positive FBs in test groups were significantly deeper than those in control groups.The transcription levels of IGF-1 mRNA in FBs 48 h after treatment with fluoride except that at a concentration of 20 mg /L increased at various degrees,while showed no significant difference with those in control groups.Conclusion Fluoride stimulated the expression of IGF-1 in FBs in both 2D and 3D cultures significantly,indicating that IGF-1 might play an important role in enhancing the osteoplastic function of FBs with fluoride.

在近来的研究中,作者提出氧化应激和内质网应激参与了氟骨症成骨细胞的活化~([1-2]).关于氧化应激的作用,已在相关论文中有所论述~([3-4]),本文中,作者将着重探讨内质网应激在氟骨症发生机制中的作用。

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.

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.

目的 探讨氟中毒大鼠血清中OPG、RANKL、IL-1β和TNFα的变化及它们之间的关系.方法 通过低钙与含氟饮食建立氟中毒大鼠模型,采用Elisa法测定氟中毒大鼠血清中OPG、RANKL、IL-1β和TNFα表达.结果 氟摄入可以提高血清OPG、IL-1β和TNFα水平;低钙饮食提高血清OPG水平,不影响IL-1β和TNFα水平;低钙与氟摄入协同能提高血清RANKL水平.结论 慢性氟中毒大鼠血清中OPG、RANKL、IL-1β和TNFα发生了变化;OPG升高是主要的,可以反应机体内破骨或协同破骨因素总的变化程度.

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.

Objective To observe the expression of c-fos mRNA and protein in fluoride treated mouse fibroblast (FB) and osteoblast (OB) and to further explore the effects of c-fos in the osteogenic action of FB. Methods Mouse FB and OB were divided into control group and six fluoride groups (0, 0.0001, 0.0010, 0.1000, 1.0000, 10.0000,20.0000 mg/L F-), and the levels of c-fos protein at 2,4,24,48,72 h and c-fos mRNA at 48 h were measured by using ELISA and RT-PCR methods. Results Compared with the control group, fluoride increased the content of c-fos protein obviously in all FB group(P<0.01); and it is increased in 0.0001,0.0010 mg/L groups at 48 h (0.73±0.04, 0.64±0.14) and 0.0001 mg/L group at 72 h(0.70±0.17) in OB compared with the control group (0.32±0.04,0.27±0.05, P<0.01). Compared with the control group (0.95±0.11), RT-PCR revealed an increasing tendency of the expression of c-fos mRNA at 48 h in FB (1.06±0.16, 1.06±0.12,1.12±0.16,1.04±0.15,1.04±0.10,1.15±0.29), but the difference was not statistically significant(P>0.05); however, a statistically significant difference(P<0.01) of c-fos mRNA in 20.0000 mg/L group(1.40±0.17) in O B was found compared with the control group (1.06±0.06). Conclusion The higher expression of c-fos mRNA and protein in FB induced by fluoride may play an important role in the transformation of osteoblastic phenotype as well as increase the osteogenesis ability in FB.

Proteomical analysis is defined as the characterization of the entire set of protein encoded a genome. Two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) are main techniques used in proteomic analysis to achieve information about protein expression profiles. Knowledge about the mechanism of skeletal fluorosis can be gained by recognizing changes in protein expression. To better understand the skeletal fluorosis process, osteoblasts isolated from calvarial of neonatal mouse were cultured and treated with 2 ppm fluoride for 72 h, and proteins of the osteoblast were profiled by 2-DE. With the analysis of Image-Master 2D analysis software, we detected a total number of 493 matching spots on 2-DE images. Among them, 28 protein spots showed twofold significant alteration (P < 0.05) in fluoride-exposed groups. Moreover, 12 proteins were identified by MALDI-TOF MS. These identified proteins in fluoride-exposed group were associated with cell proliferation, metabolism, and oxidative folding. Thus, our study provides useful information on fluoride-related changes of proteome and shows that proteomical analysis is a powerful methodology for the better understanding of skeletal fluorosis.

Objective To study the influence of fluoride on the expression of Runx2 in suckling rat osteoblasts. Methods Osteoblasts obtained from calvarium of suckling Wistar rats were cultured in the media supplemented with NaF at different doses(0, 1,2 and 4 rag/L), and Runx2 Mrna expression and protein expression were evaluated by RT-PCR and ELISA, respectively. Results Runx2 Mrna expression in suckling rat osteoblasts cultured in vitro significantly increased after exposure to NaF for 48 h at different doses (0.613±0.055, 0.773±0.070 and 0.775±0.070 for 1,2 and 4 mg/L,respecfively) compared to the control (0.482±0.043 ,P< 0.05). Runx2 Mrna expression further increased after 72 h exposure to NaF(0.969±0.048,1.229±0.061,1.255± 0.063 for 1,2 and 4 mg/L, respectively) ,which is significantly higher than the control(0.724±0.036,P<0.05) and corresponding groups at 48 h. NaF doses and exposure time exhibited a significant synergistic effect on Runx2 Mrna expression (P<0.05). Similarly, NaF also enhanced Bunx2 protein expression in suckling rat osteoblasts cultured in vitro. Significant differences were observed between groups exposed to NaF (1,2 and 4 rag/L) and control at48 h post-exposure (0.141±0.007, 0.143±0.008, 0.143±0.011 vs 0.129±0.012, P<0.05) as well as 72 h post-expesure(0.156±0.014, 0.168±0.018, 0.162±0.0100 vs 0.137±0.016, P<0.05). In addition, Runx2 protein expression at 72 h post-exposure was significantly higher than that at 48 h. Conclusions The results suggested that NaF could increase Runx2 expression in suckling rat osteoblasts with a synergistic effect between the doses and exposure time.

目的 探讨氟对体外培养的大鼠骨髓基质细胞(MSCs)增殖能力与成骨能力的影响.方法 体外培养大鼠MSCs,噻唑蓝(MTT)比色法分析不同染氟水平下MSCs的增殖能力;光、电镜下观察不同染氟水平下MSCs成骨转化能力和相应超微结构变化.结果 与对照组比较,低水平染氟(0.02 mg/L)96 h后促进MSCs增殖(P＜0.05);较高水平染氟(0.05～1.00 mg/L)72 h即可促进MSCs增殖(P＜0.05或＜0.01);高水平染氟(10.00、20.00mg/L)对MSCs具有抑制增殖和促细胞凋亡作用(P＜0.01).较高水平染氟(2.00～20.00 mg/L)时MSCs成骨转化受抑(P＜0.01),较低水平染氟(0.01～1.00 mg/L)时MSCs成骨转化增强(P＜0.01).结论 低水平染氟促进MSCs增殖,成骨转化能力增强;高水平染氟抑制MSCs增殖,促进细胞凋亡,抑制MSCs成骨转化能力。

In the present study, the effect of fluoride on intracellular free calcium ([Ca2+]i) and Ca2+-ATPase of renal cells were examined. Some paradoxical experimental results about the mechanism of fluoride toxicity were observed. In vivo, 48 Wistar rats were divided into 4 groups, and half of rats were treated with sodium fluoride (NaF) by drinking water (per liter of tap water containing 100 mg F-). Compared with the respective control, the level of [Ca2+]i of the kidney in two fluoride-treated rats obviously increased (p < 0.05); and the activity of Ca2+-ATPase in 100 mg F-/L groups with a standard diet did not significantly increase, and the enzyme activity in 100-mg F-/L group with a low-calcium diet decreased significantly compared to the 100 mg F-/L group with a standard diet (p < 0.05). In vitro, renal tubular cells were cultured and respectively exposed to 1.0, 5.0, 7.5, and 12.5 mg/L fluoride in the culture medium. Results showed the significantly elevated activity of Ca2+-ATPase in the cells exposed to 1.0 and 5.0 mg/L fluoride (p < 0.05), and this enzyme activity indicated inhibitory trend in cells of the 7.5- and 12.5-mg/L fluoride-treated group. To sum up, the effect of fluoride on Ca2+-ATPase is a similar to a dose-effect relationship phenomenon characterized by low-dose stimulation and high-dose inhibition, and the increase of [Ca2+]i probably plays a key role on the mechanism of renal injury in fluorosis.

目的 探讨单纯氟与骨转换条件下氟对骨髓基质细胞(MSCs)表达骨形成蛋白2(BMP2)mRNA和Ⅰ型胶原(Col Ⅰ)mRNA的影响.方法 体外培养大鼠MSCs,单纯加入不同质量浓度的氟与骨转换条件下加入不同质量浓度的氟处理24 h,通过反转录-聚合酶链反应(RT-PCR)方法,观察MSCs表达BMP2 mRNA和Col Ⅰ mRNA的变化.结果 单纯染氟时,BMP2 mRNA在氟10.00 mg/L时受抑;Col Ⅰ mRNA在氟0.10～1.00mg/L升高.骨转换条件下,BMP2 mRNA在氟0.50～1.00mg/L升高,2.00～10.00ms/L时受抑;Col Ⅰ mRNA在氟0.10～1.00 ms/L升高,10.00 ms/L时受抑.结论 单纯染氟与骨转化条件下染氟都能影响MSCs表达BMP2和Col Ⅰ mRNA;骨转化条件下染氟对MSCs表达BMP2 mRNA的影响较单纯染氟时敏感.