title: [Effects of fluoride on Fas signal pathway in rat incisor cells].
abstract: OBJECTIVE
  To investigate the effects of fluoride on Fas expression, caspase-3 and caspase-8 activity and apoptosis in rat incisor cells.
  
  
  METHODS
  Forty male SD rats were divided into 4 groups randomly and provided with distilled water containing NaF at the doses of 0, 10, 50 and 100 mg/L respectively. Each group had 10 animals. Five animals were sacrificed at 60 and 90 days respectively. Fas expression was measured with immunohistochemistry, and colorimetric assay was used to examine caspase-3 and caspase-8 activity with enzyme-labelled meter. The apoptosis was detected by flow cytometry in mandibular incisor cells.
  
  
  RESULTS
  NaF at the doses of 10, 50 and 100 mg/L for 60 d and 90 d caused Fas overexpression, promoted activity of caspase-3 and caspase-8, increased apoptosis rate in mandibular incisor cells. At 60 days, the value of Fas expression was 0.1819 ± 0.0025 for control, 0.2120 ± 0.0084 for 10 mg/L NaF group, 0.2283 ± 0.0183 for 50 mg/L NaF group, 0.2818 ± 0.0233 for 100 mg/L NaF group. At 90 days, the value of Fas expression was 0.2077 ± 0.0289 for control, 0.2216 ± 0.0105 for 10 mg/L NaF group, 0.2377 ± 0.0059 for 50 mg/L NaF group, 0.2775 ± 0.0088 for 100 mg/L NaF group. Statistics analysis yielded close relationship between the dose of NaF in water and the Fas expression, and also between the dose of NaF in water and caspase-3 activities, and the relative coefficient was 0.9728 (60 d, P < 0.01) and 0.9889 (90 d, P < 0.01) for Fas expression, 0.9533 (60 d, P < 0.01) and 0.9849 (90 d, P < 0.01) for caspase-3 activity respectively. Apoptosis rate and caspase-8 activity also had close relationship with the NaF doses, and the relative coefficient was 0.9733 (90 d, P < 0.01) for apoptosis, 0.9928 (90 d, P < 0.01) for caspase-8. At the doses of 10, 50 and 100 mg/L NaF for 60 d and 90 d, obvious relationship was found between Fas expression and caspase-3 activity, and the relative coefficient was 0.9619 (60 d, P < 0.01) and 0.9912 (90 d, P < 0.01). Obvious relationship between Fas expression and apoptosis, between Fas expression and caspase-8 activity was found in groups for 90 d, and the relative coefficient was 0.9841 (P < 0.01) for apoptosis, 0.9767 (P < 0.01) for caspase-8.
  
  
  CONCLUSIONS
  Fluoride could induce Fas overexpression and mediate caspase activation and apoptosis at the doses of 10, 50 and 100 mg/L for 60 d and 90 d in rat mandibular incisor cells.
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Guangdong Pharmaceutical University, Guangdong Key Laboratory of Molecular Epidemiology, Guangzhou, China.
authors.forename: Ling-Fei
authors.initials: LF
authors.lastname: He
authors.forename: Zhi-Hui
authors.initials: ZH
authors.lastname: Zou
authors.forename: Yuan-Fang
authors.initials: YF
authors.lastname: Zhong
authors.forename: Qian
authors.initials: Q
authors.lastname: Xie
authors.forename: Xuan
authors.initials: X
authors.lastname: Pan
authors.forename: Ri-An
authors.initials: RA
authors.lastname: Yu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002327:Cariostatic Agents / Q000008:administration & dosage / Q000494:pharmacology; D053148:Caspase 3 / Q000378:metabolism*; D053181:Caspase 8 / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D007180:Incisor / Q000166:cytology / Q000378:metabolism; D008297:Male; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D012969:Sodium Fluoride / Q000008:administration & dosage / Q000494:pharmacology*; D019014:fas Receptor / Q000378:metabolism*
chemical_list: D002327:Cariostatic Agents; D019014:fas Receptor; D012969:Sodium Fluoride; C505410:Casp3 protein, rat; C505528:Casp8 protein, rat; D053148:Caspase 3; D053181:Caspase 8