West China Journal of Stomatology

Previous Articles     Next Articles

Excessive fluoride inducing calcium overload and apoptosis of ameloblasts

Zhang Ying1, Ma Lin1, Li Jian1, Zhong Ming2, Zhang Kaiqiang1, Gu Hefeng1.   

  1. 1. Dept. of Preventive Dentistry, School of Stomatology, China Medical University, Stomatological Institute of Liaoning Province, Shenyang 110002, China; 2. Central Laboratory, School of Stomatology, China Medical University, Shenyang 110002, China
  • Online:2014-12-01 Published:2014-12-01

Abstract:

Objective To study the effect of excessive fluoride on calcium overload and apoptosis in cultured rat ameloblasts in vitro. Methods Logarithmic-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. Results NaF 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. Conclusion Excessive fluoride-induced calcium overload in ameloblasts and further caused endoplasmic reticulum stress-mediated apoptosis.

Key words: fluoride, ameloblasts, calcium overload, calreticulin, apoptosis