Hypoxia and Reoxygenation Augment Bone-Resorbing Factor Production From Human Periodontal Ligament Cells
- Autores: Hitoshi Motohira, Joichiro Hayashi, Junichi Tatsumi, Kitetsu Shin
- Localización: Journal of periodontology, ISSN 0022-3492, Vol. 78, Nº. 9, 2007, págs. 1803-1809
- Idioma: inglés
- Enlaces
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Resumen
Background: Oxygen deficiency caused by occlusal trauma and smoking may be associated with bone resorption in periodontitis. In the present study, the effects of hypoxia and reoxygenation on the production of bone-resorbing factors by cultured human periodontal ligament (PDL) cells were examined.
Methods: Human PDL cells were cultured in 1% O2 (hypoxia), 20% O2 (normal oxygen tension [normoxia]), or an oxygen concentration that went from 1% to 20% (reoxygenation). The concentrations of bone-resorbing factors, i.e., vascular endothelial growth factor (VEGF), interleukin (IL)-6 and -1β, tumor necrosis factor-alpha (TNF-α), and prostaglandin E2 (PGE2), in the cell culture supernatants were determined by enzyme-linked immunosorbent assay. Expression of the corresponding mRNAs was detected by reverse transcription-polymerase chain reaction.
Results: Significantly higher extracellular concentrations of VEGF and IL-6 were detected along with greater corresponding mRNA expression in the hypoxia group compared to the normoxia group. The protein production and mRNA expression of IL-1β were observed only in the hypoxia group. Neither TNF-α nor PGE2 was detectable in samples from either group, whereas cyclooxygenase-2 mRNA was detected. However, PGE2 was detected after reoxygenation. Furthermore, VEGF and IL-6 and -1β production also tended to increase in extracellular concentration and mRNA level after reoxygenation.
Conclusion: Hypoxia and reoxygenation may stimulate the PDL to produce VEGF, IL-6 and -1β, and PGE2, which could result in the resorption of alveolar bone in periodontitis.
