Figure 3.

Effects of rolipram and PKA inhibitor on the expression of MKP-1 mRNA and phosphorylation of CREB and p38 MAPK in activated J774 macrophages. (A) J774 cells were pre-incubated with rolipram (2 μM) or PKA inhibitor 6–22 amide (PKAi, 5 μM) for 1 h and stimulated then with LPS (10 ng·mL⁻¹) for 1 h. MKP-1 mRNA was detected by quantitative RT-PCR and normalized against GAPDH mRNA levels. The results are expressed as mean ± SEM, number of repeats = 8. (B, C) J774 cells were pre-incubated with rolipram (2 μM) or PKA inhibitor 6–22 amide (PKAi, 5 μM) for 1 h and stimulated with LPS (10 ng·mL⁻¹) for 30 min and phophorylated CREB and phosphorylated p38 MAPK were detected by Western blot. The chemiluminescent signal was quantified, and the phosphorylated CREB and p38 MAPK were normalized against total CREB and total p38 MAPK respectively. Phosphorylated CREB and p38 MAPK levels are expressed in arbitrary units, LPS-simulated cells were set as 100%, and the other values were related to that value. The results are expressed as mean ± SEM, number of repeats = 8. One-way anova with Bonferroni's post-test was performed and statistical significance is indicated as *P < 0.05, **P < 0.01 and ***P < 0.001.