Effect of Dexamethasone on proliferation and expression of fibroblast growth factor mRNA in human embryo lung fibroblasts exposed to hyperoxia

Objective To explore the effect of Dexamethasone (DEX) on the proliferation and the expression of fibroblast growth factor(FGF)-1, FGF-2 and interleukin-6(IL-6) mRNA in hyperoxia-exposed human embryo lung fibroblasts(MRC-5). Methods High oxygen volume fraction of 950 mL/L was used to establish hyperoxia-damaged cell models, then treated with different concentrations of DEX (10-4, 10-6, 10-8, 10-9, 10-10, 10-11, 10-12 mol/L), respectively.The proliferation activity of the cells was evaluated by methyl thiazolyl tetrazolium (MTT) at 24 h, 48 h, 72 h, and the optimal hyperoxia-exposed time and concentration of DEX were chosen; then they were divided into air group, hyperoxia group and hyperoxia+ DEX group.The mRNA expressions of FGF-1, FGF-2 and IL-6 were detected by quantitative real-time PCR at 48 h. Results Cell proliferation activity of the hyperoxia group was lower than that of the air group and there were significant differences at 48 h and 72 h (all P<0.05). Compared with the hyperoxia group, cell proliferation activity of the hyperoxia + DEX group increased with the concentration of DEX decreasing, reaching the peak at 10-9 mol/L, and then gradually decreased with the concentration of DEX decreasing.Cells were cultured for 48 h, compared with the air group, the level of FGF-1 mRNA was lower, FGF-2 and IL-6 mRNA were higher in the hyperoxia group (P<0.05). Compared with hyperoxia group, the level of FGF-1 mRNA was higher, FGF-2 and IL-6 mRNA were lower in hyperoxia + DEX group (P<0.05). Conclusions Exposure to high oxygen volume fraction of 950 mL/L for 48 h can cultivate optimal hyperoxia-damaged cell models, and DEX can protect the cell from hyperoxia injury and 10-9 mol/L was the optimal concentration.Enhanced the expression of FGF-1 mRNA and inhibited expression of FGF-2 mRNA may be one of the mechanism that DEX protects the cells from hyperoxia injury. Key words: Dexamethasone; Hyperoxia; Human embryo lung fibroblasts; Fibroblast growth factor