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.

Objective To cxplore the variation of the range of motion (ROM) of operative level after different heights of artificial cervical disc replacement,and to provide guidance for clinical work in selecting appropriate height of artificial cervical disc prosthesis.Methods The preoperative cervical anteroposterior and lateral Ⅹ-rays of 9 fresh male cadaveric cervical spine specimens were obtained to measure the intervertebral height of C5-6,and 3 screened specimens with the height of about 5 mm were included in the experiment.The experiment was designed to test self-control,and other four groups of cervical specimens including intact group,appropriate height (5 mm) of C5.6 artificial cervical disc replacement group,1mm increased (6 mm) group and 2 mm increased (7 mm) group were made biomechanical test sequentially.The specimens were fixed to the cervical three-dimensional movement machine,with a 75 N follower load and pure moments of 2 Nm for flexion/extension 、left/right bending and left/right axial rotation,to measure the ROM of operative level under the condition of changes in 0.2 Nm/s.Results There were no significant differences in the ROM of flexion/extension,lateral bending and axial rotation between 5 mm group and intact group;the ROM of flexion/extension、lateral bending and axial rotation in 6 mm group increased compared with 5 mm group,but the difference was not statistically significant;the ROM of flexion/extension in 7 mm group was significantly less than that of intact,5mm and 6 mm group (9.5°± 1.0° vs 12.5°±0.9°、11.3°±0.8°、11.6°±0.9°),but significantly greater in axial rotation than 6 mm group (10.4°±1.4°vs 8.6°±0.3°),and there was no significant difference in lateral bending compared with other 3 groups.Conclusion 2 adjacent heights of cervical disc prostheses are implantedsuitably when testing the mold of disc prosthesis,the choice of cervical disc prosthesis with 1 mm increased can improve the ROM of operative level to some extent;while the height with 2 mm increased can lead to the ROM of flexion/extension at the operative level reduced,but the ROM of rotation shows an increasing trend.

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.