LS8 cell apoptosis induced by NaF through p-ERK and p-JNK – a mechanism study of dental fluorosis

Abstract

Objective: To investigate the possible biological mechanism of dental fluorosis at a molecular level.

Material and methods: Cultured LS8 were incubated with serum-free medium containing selected concentrations of NaF (0 ∼ 2 mM) for either 24 or 48 h. Subcellular microanatomy was characterized using TEM; meanwhile, selected biomolecules were analysed using various biochemistry techniques. Transient transfection was used to modulate a molecular pathway for apoptosis.

Results: Apoptosis of LS8 was induced by NaF treatment that showed both time and concentration dependency. The activity of caspase-3, -8, -9 was found to be increased with NaF in a dose-dependent manner. Western blot revealed that the protein expression of p-ERK and p-JNK were decreased, while the expression of p-P38 was increased. Inhibition of the p-ERK and p-JNK pathways resulted in a similar decrease for caspase-3.

Conclusion: During NaF-induced apoptosis of LS8, p-ERK and p-JNK were closely associated with induction of apoptosis, which might be a mechanism of dental fluorosis.

Keywords:

• NaF
• LS8
• apoptosis
• mitogen-activated protein kinase
• dental fluorosis

Acknowledgements

We thank Professor Yan Jin, of the Institute of Tissue Engineering and Regenerative Medicine, School of Stomatology, the Fourth Military Medical University for technical assistance.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Funding

The National Natural Science Foundation of China [No. 30972558].

Notes on contributors

Lin Zhao, Associate Professor of Oral Pathology, PhD candidate interested in tooth development. Now, focus on the the mechanism and related effectors of tooth, especially, the enamel development.

Juedan Li, MD, A junior preventive dental specialist, interested in people?s oral health, the molecular mechanism of dental fluorosis. Research area focus on the molecular mechanism of FoxO1 in dental fluorosis.

Jiali Su, MD, Dentist in department of Endodontics, interested in caries prevention and tooth development.

Malcolm L. Snead, PhD, Professor of the Biomedical Sciences, interested in biomineralization and biomaterials, tooth enamel.

Jianping Ruan, PhD, Professor of the Preventive Dentistry, interested in fluoride and dental health, caries prevention and tooth development. Now, focus on the molecule and biological basis of dental fluorosis, the mechanism and related effectors of tooth, especially, the enamel development.