1. Fluoride inhibits the response of bone cells to mechanical loading.
- Author
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Willems HM, van den Heuvel EG, Castelein S, Buisman JK, Bronckers AL, Bakker AD, and Klein-Nulend J
- Subjects
- 3T3 Cells, Actins analysis, Actins drug effects, Animals, Biomechanical Phenomena, Cell Culture Techniques, Cell Shape drug effects, Cricetinae, Cytochalasin B pharmacology, Cytoskeleton drug effects, Hydrodynamics, Mandible cytology, Mice, Nitric Oxide antagonists & inhibitors, Nitric Oxide biosynthesis, Osteoblasts drug effects, Osteoclasts drug effects, Pulsatile Flow, Stress, Mechanical, Time Factors, Cariostatic Agents pharmacology, Fluorides pharmacology, Osteocytes drug effects
- Abstract
The response of bone cells to mechanical loading is mediated by the cytoskeleton. Since the bone anabolic agent fluoride disrupts the cytoskeleton, we investigated whether fluoride affects the response of bone cells to mechanical loading, and whether this is cytoskeleton mediated. The mechano-response of osteoblasts was assessed in vitro by measuring pulsating fluid flow-induced nitric oxide (NO) production. Osteocyte shape was determined in hamster mandibles in vivo as parameter of osteocyte mechanosensitivity. Pulsating fluid flow (0.7 ± 0.3 Pa, 5 Hz) stimulated NO production by 8-fold within 5 min. NaF (10-50 μM) inhibited pulsating fluid flow-stimulated NO production after 10 min, and decreased F-actin content by ~3-fold. Fluid flow-induced NO response was also inhibited after F-actin disruption by cytochalasin B. NaF treatment resulted in more elongated, smaller osteocytes in interdental bone in vivo. Our results suggest that fluoride inhibits the mechano-response of bone cells, which might occur via cytoskeletal changes. Since decreased mechanosensitivity reduces bone mass, the reported anabolic effect of fluoride on bone mass in vivo is likely mediated by other factors than changed bone cell mechanosensitivity.
- Published
- 2011
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