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. 2014 Mar 19;9(3):e92466. doi: 10.1371/journal.pone.0092466

Figure 3. Dexamethasone totally inhibits S1P-induced IL-8 protein secretion, but only partially inhibits TNFα-induced IL-8 induced in the presence of S1P.

Figure 3

(A) To compare IL-8 secretion, growth-arrested ASM cells were treated with vehicle, S1P (1 μM), TNFα (10 ng/ml), or S1P (1 μM) in combination with TNFα (10 ng/ml). (B–C) To examine the relative corticosteroid sensitivity, cells were pretreated for 1 h with vehicle or dexamethasone (0.0001, 0.01, 1 μM) then: (B) stimulated with S1P (1 μM); (C) stimulated with TNFα (10 ng/ml); (D) stimulated with S1P (1 μM) +TNFα (10 ng/ml). After 24 h, secreted IL-8 was measured by ELISA. Statistical analysis was performed using one-way ANOVA then Fisher's post-hoc multiple comparison test, where § denotes a significant upregulation of IL-8, and * denotes a significant effect of dexamethasone on IL-8 secretion (P<0.05). Data are mean+SEM values from n = 7 primary ASM cell lines.