The Stimulation of inflammatory cytokine release under hypoxic condition in human deciduous dental pulp cells

Abstract

Objective: Oxygen plays an important role in signal transduction and regulation of cell behavior. The aim of this study was to investigate the response of SHED to hypoxia (2%O2) especially on the inflammatory cytokine release. Materials and methods: Dental pulp cells were obtained from exfoliated deciduous teeth. Cells were cultured and put under hypoxic condition (2%O2) for 6, 9, 12, and 15 hours. The number of cells was determined by metabolic assay (MTT assay). The changes in RNA expression were examined by reverse transcription polymerase chain reaction (RT-PCR) and the amount of protein was measured using enzyme-linked immunosorbent assay (ELISA). Result: The results showed that 2% oxygen could significantly up-regulate IL-6 expression and secretion after 12 hours under hypoxia condition. Cobalt chloride (CoCl2) could also increase IL-6 secretion in a dose-dependent manner. Hypoxia could up-regulate Rex-1 expression and the use of IL-6 neutralizing antibody demonstrated the role of IL-6 in Rex-1 induction. Discussion: The data from this study suggested that the HIF-1α dependent up-regulation of IL-6 expression is a late response. The hypoxia-induced IL-6 can induce Rex-1 expression in SHED and may play a role in cell tissues repair or cell proliferation/ differentiation in response to the low oxygen environment.