The purpose of this study is to discuss the feasibility of establishing capsaicin pain model and the possibility to evaluate different degrees of pain by the heart rate variability (HRV). It also aims to investigate the changes of autonomic nervous activity of volunteers during the process of pain caused by capsaicin. A total of 30 volunteers were selected, who were physically and mentally healthy, into the study. To assess the effects of capsaicin on the healthy volunteers, we recorded the Visual Analogue Scale (VAS) scores after the capsaicin stimulus. Additionally, the electrocardiogram signals and HRV analysis index before and after stimulating were also recorded, respectively. More specifically, the HRV analysis indexes included the time domain index, the frequency domain index, and the nonlinear analysis index. The results demonstrated that the activity of the autonomic nerves was enhanced in the process of capsaicin stimulus, especially for the sympathetic nerve, which exhibited a significantly differences in HRV. In conclusion, the degree of pain can be reflected by the HRV. It is feasible to establish a capsaicin pain model. And in further experiments, HRV analysis could be used as a reference index for quantitative evaluation of pain.
Autonomic Nervous System ; physiopathology ; Capsaicin ; Electrocardiography ; Feasibility Studies ; Healthy Volunteers ; Heart Rate ; Humans ; Pain ; physiopathology ; Pain Measurement ; methods

OBJECTIVETo observe the effect of different concentrations of zoledronic acid on human gingival fibroblast (HGF) cells proliferation and apoptosis, and to investigate the mechanism of bisphosphonate-related osteonecrosis of the jaw (BRONJ) caused by zoledronic acid.

METHODSDifferent concentrations (0, 0.5, l.0, 5.0, 10.0 µmol/L) of zoledronic acid acted on the HGF. After 24 hours, flow cytometry was used to detect the rate of apoptosis and methyl thiazolyl terazolium (MTT) assay used to observe the proliferation of HGF. The effect of different concentrations of zoledronic acid on cell proliferation was examined by proliferation test on day 2, 4 and 7.

RESULTSFlow cytometry showed that when the concentration of zoledronic acid was 0, 0.5, 1.0, 5.0, 10.0 µmol/L, the apoptosis rate was (0.67 ± 0.50)%, (2.13 ± 0.21)%, (3.27 ± 0.23)%, (4.17 ± 0.35)%, (9.87 ± 1.79)% respectively. The difference in HGF cells between control group and zoledronic acid groups was significant (P < 0.05) at three concentrations of zoledronic acid (1.0, 5.0, 10.0 µmol/L). The cell proliferation test showed an concentration-time dependent effect. With increase of concentration and time, the cell proliferation was significantly inhibited. There was significant difference in absorbance value among the different concentration groups (P < 0.05).

CONCLUSIONSZoledronic acid can inhibit HGF proliferation and promote its apoptosis.

Apoptosis ; drug effects ; Bisphosphonate-Associated Osteonecrosis of the Jaw ; etiology ; Bone Density Conservation Agents ; pharmacology ; Cell Proliferation ; drug effects ; Coloring Agents ; Diphosphonates ; pharmacology ; Dose-Response Relationship, Drug ; Fibroblasts ; drug effects ; physiology ; Flow Cytometry ; Gingiva ; cytology ; Humans ; Imidazoles ; pharmacology ; Tetrazolium Salts ; Thiazoles ; Time Factors