OBJECTIVETo study the effect of excessive fluoride on calcium overload and apoptosis in cultured rat ameloblasts in vitro.

METHODSLogarithmic-phase ameloblasts (HAT-7) were treated with 0, 0.4, 0.8, 1.6, 3.2, and 6.4 mmol · L(-1) sodium fluoride (NaF) solution. Cell activities were detected by using a Cell Counting Kit 8 (CCK-8) assay after 48 h of treatment. The effect of fluoride on cell apoptosis was analyzed by using flow cytometry. Excessive fluoride-induced calcium concentration and calreticulin expression changes in ameloblasts were detected by using laser scanning confocal microscopy, Western blot analysis, and real-time quantitative polymerase chain reaction.

RESULTSNaF inhibited ameloblast activity at 1.6, 3.2, and 6.4 mmol · L(-1) (dose-dependent) after 48 h of induction. The Ca2+ fluorescence intensity of HAT-7 cells incubated with 1.6 and 3.2 mmol · L(-1) NaF was higher than that in the control group. The fluoride-induced early-stage apoptosis of ameloblasts after 48 h of induction and the early-stage apoptosis rate was positively correlated with fluoride concentration. Calreticulin mRNA expression in HAT-7 cells was higher than that in the control group after 48 h of incubation with 0.8, 1.2, and 1.6 mmol · L(-1) NaF.

CONCLUSIONExcessive fluoride-induced calcium overload in ameloblasts and further caused endoplasmic reticulum stress-mediated apoptosis.

Ameloblasts ; Animals ; Apoptosis ; Calcium ; Calcium Fluoride ; Fluorides ; Phosphates ; Rats ; Sodium Fluoride

Objective:To evaluate the effect of fluoride on the viability of rat ameloblast HAT-7 cells and calcium concentration in the cells.Methods:HAT-7 cells were exposed to NaF at 0,0.4,0.8,1.6,3.2 and 6.4 mmol/L for 24,48 and 72 h respectively. CCK-8 assay was performed to examine the cells proliferation;the apoptosis rate was determined by flow cytometry;Ca2 +concentration in the cells was detected by laser scanning confocal microscopy.Results:The cell proliferation was increased by NaF at 0.4 mmol/L and 0.8 mmol/L,whereas inhibited at 1.6 mmol/L and above.The effects were in a time-dependent manner.NaF increased apoptosis of the cells and increased Ca2 + concentration in the cells in a concentration-dependent manner.Conclusion:Fluoride at low doses promotes proliferation,at high doses inhibits proliferation of HAT-7 cells.NaF of 1.6 mmol/L or more induces apoptosis of HAT-7 cells and in-duce Ca2 + overloading in the cells.

Objective To explore the effect of robot assistance on the gait kinematics of hemiplegic persons after a stroke.Methods Forty hemiplegic stroke patients were randomly divided into an experimental group and a control group,each of 20.Both groups were given routine neurological medication and rehabilitation training,while the experimental group was additionally provided with 20 minutes of robot-assisted gait training daily,six times a week,for 8 weeks.Before and after the intervention,both groups' motor function,balance,step length and pace were evaluated,as well as their pelvic rotation angles,side inclination,vertical displacement and lateral displacement.The Fugl-Meyer assessment for the lower extremities (FMA-LE) was used along with the Berg balance scale (BBS),the gait analysis system of Biodex Gait Trainer-2 equipment.Results After the treatment,the average FMA-LE score,BBS score,pace and step length of the experimental group were all significantly better than the before the treatment and significantly better than the control group's averages after the treatment.The improvements observed in the pelvic rotation angle,side inclination,vertical displacement and lateral displacement were all significant.Conclusion Robot assistance can usefully supplement routine rehabilitation training after stroke.It can improve control of the pelvis,enhance walking and balance and generally improve the motor function of the lower extremities.

Objective:To explore the effect of robot-assisted training and repetitive transcranial magnetic stimulation (rTMS) on the lower limb function of hemiplegic stroke survivors.Methods:Forty hemiplegic stroke patients were randomly divided into a treatment group ( n=20) and a control group ( n=20). Both groups were given routine rehabilitation training and robot-assisted walking training, but the treatment group was additionally treated with rTMS at 1Hz applied to the primary motor cortex M1 area at an intensity of 80% of the resting motor threshold. The stimulation time was 5 seconds at 5-second intervals, 600 pulses each time, five times a week for 8 weeks. Lower limb motor function, balance and walking function were assessed before and after the intervention using the Fugl-Meyer assessment for the lower extremities, the Berg balance scale and the Holden walking function scale. Results:There was no significant difference between the two groups in any measurement before the training, but after the intervention all of the measurements had improved significantly in both groups, with the average Fugl-Meyer score, Berg score and Holden grading significantly better in the treatment group.Conclusion:Repetitive transcranial magnetic stimulation can improve the effectiveness of robot-assisted walking training in improving lower limb motor function, balance and walking after a stroke.

Objective:To explore the effect of a pelvis-assisting rehabilitation robot on lower limb function and knee proprioception after cerebral infarction.Methods:Forty hemiplegic cerebral infarction survivors were randomly divided into an experimental group and a control group, each of 20. Both groups were given routine neurological medication and rehabilitation training, while the experimental group was additionally provided with 20 minutes of robot-assisted gait training daily, five times a week for four weeks. Before and after the intervention, motor function, balance, walking function and knee joint proprioception were assessed using the simplified Fugl-Meyer lower limb assessment, the Berg balance scale, functional ambulation categorization and the Humac Norm isokinetic tester.Results:After the treatment, significant improvement was observed in all of the above measurements in both groups, but the improvements were significantly greater in the experimental group.Conclusions:Robotic pelvic assistance can effectively improve lower limb motor function, balance, knee proprioception and walking after cerebral infarction.

Objective:To explore any effect of training assisted by a pelvic rehabilitation robot on trunk control and walking after cerebral infarction.Methods:Forty cerebral infarction survivors with hemiplegia were randomly divided into an experimental group and a control group, each of 20. Both groups were given routine neurological medication and rehabilitation training, while the experimental group was additionally provided with 20 minutes of robot-assisted gait training daily, five times a week, for 4 weeks. Before and after the intervention, the motor function, walking function, trunk control and pelvic movement were assessed using a simplified version of the Fugl-Meyer assessment (FMA-LL), functional ambulation categories (FAC) and the trunk control test (TCT).Results:After the treatment, significant improvement was observed in all of the above measurements in both groups. The average FMA-LL, FAC and TCT results of the experimental group as well as their average pelvic lateral displacement, height displacement, rotation angle and roll angle were all significantly superior to the control group′s averages.Conclusions:Robot-assisted training can effectively improve lower limb motor functioning, trunk control, walking and pelvic motion after cerebral infarction, with better curative effect than routine rehabilitation training alone.