Different Effects of Fluoride Exposure on the Three Major Bone Cell Types
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Fluoride accumulates and is toxic to bones. Clinical bone lesions occur in a phased manner, being less severe early in the natural course of skeletal fluorosis. Previous research rarely focused on osteocyte, osteoclast, and osteoblast at the same time, although these three types of cells are involved in the process of fluorosis. In this study, commitment of bone cells was performed according to their respective characteristics. Osteocyte-like cells were verified by protein expression of sclerostin (SOST) in IDG-SW3 cell culture with mineral medium. Positive tartrate-resistant acid phosphatase (TRACP) staining, characteristic of osteoclasts, is observed in RAW264.7 cells after administration of RANKL. We successfully purified a high percentage (94%) of bone mesenchymal stem cells (BMSCs) co-expressing CD34 and CD44. Parallel studies were performed to observe cell viability and apoptosis rates in osteocyte, osteoclast, and osteoblast like cells by using MTT and Annexin V FITC assays. Our results demonstrated that osteocytes have a strong tolerance to high fluoride concentrations, while osteoclasts are more sensitive to changes of fluoride dose. The range of anabolic action of fluoride concentration on osteoblast was narrow. Notably, fluoride exposure aggravated apoptosis of osteocyte and osteoclast induced by administration of PTH and TGF-β, respectively. In short, three types of bone cells display disparate responses to fluoride exposure and to PTH- and TGF-β-induced apoptosis.
KeywordsSodium fluoride Osteoblast Osteoclast Osteocyte Apoptosis
This study was supported by the National Natural Science Foundation of China (grant number 81673111, Project “Study on role of osteocyte and PTH/TGF-beta signaling pathway in the mechanism of bone turnover occurred in skeletal fluorosis”), the Natural Science Foundation of Jilin Province of China (20180101151JC).
This study was funded by Project [Study on role of osteocyte and PTH/TGF-beta signaling pathway in the mechanism of bone turnover occurred in skeletal fluorosis] supported by National Natural Science Foundation of China (grant number 81673111) and by the Natural Science Foundation of Jilin Province of China (20180101151JC).
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Conflict of Interest
The authors declare that they have no conflict of interest.
- 3.Bhawal UK, Lee HJ, Arikawa K, Shimosaka M, Suzuki M, Toyama T, Sato T, Kawamata R, Taguchi C, Hamada N, Nasu I, Arakawa H, Shibutani K (2015) Micromolar sodium fluoride mediates anti-osteoclastogenesis in Porphyromonas gingivalis-induced alveolar bone loss. Int J Oral Sci 7(4):242–249CrossRefPubMedPubMedCentralGoogle Scholar
- 17.Koide M, Kobayashi Y (2018) Regulatory mechanisms of sclerostin expression during bone remodeling. J Bone Miner Metab. https://doi.org/10.1007/s00774-018-0971-7
- 19.Hayashi M, Nakashima T, Yoshimura N et al (2019) Autoregulation of osteocyte Sema3A orchestrates estrogen action and counteracts bone aging. Cell Metab S1550-4131(18):30758–30757Google Scholar