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Objective:To study the effects of fluoride exposure on skeletal development of zebrafish larvae and its possible molecular mechanisms.Methods:Six hours post fertilization(6 hpf) wild-type zebrafish embryos were selected and exposed to sodium fluoride [NaF, control group (0 mg/L NaF), low fluoride group (25 mg/L NaF) and high fluoride group (100 mg/L NaF)] for 9 days. Fluorine ion selective electrode was used to detect the overall fluorine content of zebrafish larvaes, and the death and development of zebrafish larvaes were observed and counted. Bone mineralization and chondrogenesis of the zebrafish larvaes were analyzed by alizarin red staining and alcin blue staining, respectively. The expression levels of sry-related-high-mobilty-group box 9a (Sox9a), osteprotegerin (OPG) and receptor-activator of nuclear factor kappa beta ligant (RANKL) were analyzed by real-time quantitative PCR.Results:Compared with control group [(0.12 ± 0.01) μg/140 larvaes], the overall fluorine contents of zebrafish larvaes in low fluoride group [(0.28 ± 0.03) μg/140 larvaes] and high fluoride group [(0.64 ± 0.10) μg/140 larvaes] were significantly higher, and the differences were statistically significant ( P < 0.05). Compared with control group, zebrafish larvaes in high fluoride group had shorter body length, higher swim bladder loss rate and higher spinal curvature rate ( P < 0.05). The alizarin red staining area, integrated optical density (IOD) and the number of mineralized vertebrae were higher in low fluoride group, while the alcin blue staining area of cartilage formation was lower ( P < 0.05). In the high fluoride group, alizarin red staining area, IOD and the number of mineralized vertebrae were lower, while the alcin blue staining area of cartilage formation was higher ( P < 0.05). Compared with control group, the expression levels of OPG mRNA and OPG/RANKL mRNA in low fluoride group were higher ( P < 0.05); the expression level of RANKL mRNA was higher in high fluoride group, while the expression level of OPG/RANKL mRNA was lower ( P < 0.05). Conclusion:A short period of fluoride exposure from zebrafish embryo to zebrafish larvae can cause abnormal bone development of zebrafish larvae, which may be related to endochondral osteogenesis and OPG/RANKL pathway.
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Objective To investigate the influence of inhibited gene expression of fisson 1 (Fis1) gene on the level of Fis1,mitofusin 1 (Mfn1) and mitochondrial membrane potential in SH-SY5Y cells with fluorine,to study the role of mitochondrial dynamic balance in the pathogenesis of chronic fluorosis.Methods SH-SY5Y cells were cultured in vitro,when adherent cells entered the logarithmic phase,using a group design,they were divided into four groups:blank control group (control),fluoride group [2 mmol/L sodium fluoride (NaF)],fluoride negative control group (2 mmol/L NaF + non-specific siRNA) and the gene-silencing group (2 mmol/L NaF + specific siRNA-Fis1).The protein expression levels of Fis1 and Mfn1 were measured by Western blotting;the mRNA expression levels of Fis1 and Mfn1 were measured by Real-time PCR;and the levels of the mitochondrial membrane potential was detected by mitochondrial membrane potential detection kit.Results Compared with control (1.37 ± 0.18,1.00 ± 0.04;1.57 ± 0.19,1.00 ± 0.04;1.00 ± 0.10),the expression levels of Fisl protein (1.72 ± 0.04) and mRNA (1.48 ± 0.13) in fluoride group were increased,the expression levels of Mfn1 protein (0.87 ± 0.02) and mRNA (0.69 ± 0.07) in fluoride group were decreased,the level of mitochondrial membrane potential (0.76 ± 0.13) was decreased (P ＜ 0.05).Compared with control,the expression levels of Fis1 protein (0.79 ± 0.07) and mRNA (0.06 ± 0.03) in gene-silencing group were decreased,the expression levels of Mfn1 protein (1.71 ± 0.04) and mRNA (1.52 ± 0.05) in gene-silencing group were increased (P ＜ 0.05),the level of mitochondrial membrane potential (0.94 ± 0.01) was decreased.Compared with fluoride group,the expression levels of Fis1 protein and mRNA in gene-silencing group were decreased,the expression levels of Mfn1 protein and mRNA in gene-silencing group were increased,the level of mitochondrial membrane potential in gene-silencing group was increased (P ＜ 0.05).Conclusion Gene expression inhibition of Fis1 gene can reduce the mitochondrial division and damage of mitochondrial membrane potential in SH-SY5Y cells induced by fluoride.
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Objective To evaluate the influence of fluoride on mitochondrial membrane potential of neuroblastoma SH-SY5Y cells,and on the expression levels of mitochondrial proteins mitofusion 1 (Mfn1) and fission 1 (Fis1).Methods A stable and feasible culture method of SH-SY5Y cells in vitro was established with different concentration of sodium fluoride [0.0 (control),0.4,2.0 and 4.0 mmol/L],and various periods exposure of 6,12,24,48 h;the mitochondrial membrane potential of SH-SY5Y cells was detected by mitochondrial membrane potential assay kit (JC-1);and the expression levels of Mfn1 and Fis1 proteins were detected by Western blotting.Results Compared with the control group (1.63 ± 0.18,1.13 ± 0.15,1.30 ± 0.02) for various periods exposure (6,12,48 h),the red/green fluorescence ratios of the mitochondrial membrane potential of SH-SY5Y cells exposed to 2.0 and 4.0 mmol/L of sodium fluoride were decreased significantly (1.01 ± 0.10,0.80 ± 0.04;0.75 ± 0.13,0.62 ± 0.10;0.82 ± 0.01,0.56 ± 0.04,P ＜ 0.05);compared with the control group (0.93 ± 0.03,1.05 ± 0.07,1.17 ± 0.04) for various periods exposure,the expression levels of mitochondrial Mfn1 protein were decreased significantly in 0.4,2.0,4.0 mmol/L sodium fluoride groups (6,12,48 h:0.75 ± 0.02,0.65 ± 0.05,0.57 ± 0.06;0.83 ± 0.06,0.79 ± 0.06,0.69 ±0.06;0.98 ± 0.05,0.73 ± 0.07,0.62 ± 0.09,P ＜ 0.05).Compared with the control group (0.90 ± 0.05) for exposure time 12 h,the expression levels of Fis1 protein were increased significantly in 2.0,4.0 mmol/L sodium fluoride groups (1.14 ± 0.06,1.23 ± 0.06,P ＜ 0.05).Conclusions The mitochondrial membrane potential and the expression levels of mitofusion 1 and fission 1 of SH-SY5Y cells treated with fluoride are abnormal,which might be associated with the theory of nerve cell damage from high oxidative stress.
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Objective To observe the effects of fluorosis on the levels of endogenous cystathionine beta-synthase (CBS) and hydrogen sulfide (H2S) in rats.Methods According to body weight,forty-eight Sprague-Dawley rats (body weight 105-180 g) were divided into three groups by a random number table(16 rats in each group,half male).Fluorine contents of the feed in control group,low-fluoride group and high-fluoride group were 9.80,15.40 and 23.80 mg/kg.After 6 months of fluorine exposure,the fluorine contents of urine and bone were determined by the method of fluorine ion-selective electrode ; H2S levels in serum and brain and the activity of CBS in brain were detected by methylene blue; and protein expression of CBS was detected by Western blotting.Results Compared with control group,dental fluorosis was found in rats of low-fluoride and high-fluoride groups.The differences of fluorine contents of urine and femur were statistically significant between groups(F =65.16,67.93,all P ＜ 0.05).The urinary and femoral fluorine in low-fluoride groups [(5.25 ± 0.45)mg/L,(1 196.54 ± 72.78)mg/kg] and high-fluoride groups[(13.17 ± 0.98)mg/L,(2 656.61 ± 170.12)mg/kg] were higher than those of control groups [(3.64 ± 0.20)mg/L,(870.71 ± 71.51)mg/kg,all P ＜ 0.05],and the increases were in a dose-dependent fashion(all P ＜ 0.01).The differences of H2S contents in serum and brain were statistically significant(F =4.83,1 456.13,all P ＜ 0.05).The H2S content in serum was higher in high-fluoride group [(17.64 ± 2.38) μ mol/L] than that of the control group [(10.29 ± 0.74) μ mol/L,P ＜ 0.01].The H2S contents in brain were higher in the low-fluoride [(364.74 ± 2.06)μmol/L] and high-fluoride groups [(513.43 ± 4.18) μmol/L] than those of the control group[(314.94 ± 0.72)μmol/L,all P ＜ 0.01],and the increase was in a dose-dependent fashion (P ＜ 0.01).The difference of CBS activity was statistically significant between groups (F =760.63,P ＜ 0.01).The CBS activities were lower in low-fluoride [(438.90 ± 2.83) mmol· kg-1· min-1] and high-fluoride groups [(529.83 ± 2.37)mmol· kg-1· min-1] than those of the control group [(596.33 ± 2.75) mmol · kg-1· min-1,all P ＜ 0.01],whereas the protein expression of CBS in brain in high-fluoride group (1.49 ± 0.08) was higher than that of the control group (1.19 ± 0.06,P ＜ 0.05).Conclusion Chronic fluorosis can affect the levels of endogenous CBS and H2,S,and the increases are in a dose-dependent fashion in addition to CBS activity.
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Objective To observe the effect of small interfering RNA(siRNA)expression plasmids targeting transforming growth factor p receptor(TαR)Ⅰ gene on the collagen synthesis of hepatic stellate cells(HSCs).Methods Three siRNA expression plasmids were designed and constructed according to TBR Ⅰ sequence.Then the plasmids were transfected into HSC-T6 using 1ipofectamine2000 reagent. The mRNA and protein expressions of TβR Ⅰ were analyzed by reverse transcription polymerase chain reaction(RT-PCR)and Western blot technique, respectively. The cell proliferation was detected using methylthiazo-lyldiphenyl-tetrazolium bromide(MTT)methods. Concentrations of haluronic acid and type Ⅲ pro-collagen in the supernatants were determined by radioimmunoassay. The data were analyzed using least significant difference(LSD).Results Three recombinant plasmids expressing siRNAs were successfully constructed and confirmed by restriction enzyme assay. Compared with the blank control,all the three recombinant plasmids could inhibit the expressions of TβR Ⅰ mRNA,of which plasmid expressing siRNA2 exhibited the strongest inhibitory effect(psiRNA1 group:t=7.354,P＜0.01;psiRNA2 group:t=9.214,P＜0.01;psiRNA3 group:t=5.967,P＜0.01).The expressions of TβR Ⅰ protein were also reduced by all the three recombinant plasmids,of which the plasmid expressing siRNA2 showed the strongest inhibitory effect(psiRNA1 group: t=6.324,P＜0.01;psiRNA2 group:t=8.741,P＜0.01;psiRNA3 group:t=4.128,P＜0.01).The proliferation activity and collagen synthesis of HSCs also decreased in all three HSC groups treated with recombinant plasmids, of which, again, plasmid expressing siRNA2 exhibited the strongest inhibitory effect. However, no significant change was observed in HSCs transfected with non-related siRNA. Conclusion Recombinant plasmids targeting TβR I can inhibit collagen synthesis, which suggests a novel target for gene therapy of liver fibrosis.