Fig. 2.

PGE₂ attenuates the induction of TNF-α by LPS. The expression of TNF-α in astrocytes (a–d) and microglia (e, f) was studied by RT-PCR and ELISA 4 and 8 h after LPS exposure. a, b LPS induced the expression of TNF-α mRNA (n = 4 replicates per time point in three independent experiments) (a) and protein in the culture medium (n = 3–5 replicates in three independent experiments) (b). c, d Treatment with PGE₂ 30 min before LPS reduces, in a dose-dependent manner (1.4–11.3 nM), the induction of TNF-α mRNA (c), and protein (d) (n = 3 replicates in three independent experiments). e, f In pure microglia cultures, treatment with PGE₂ (11.3 nM) also reduced TNF-α mRNA expression (n = 3–6 replicates in three independent experiments) (e) and protein (n = 3–6 replicates in four independent experiments) (f) at 4 h. **p < 0.01, ***p < 0.001 vs. control; &p < 0.05, &&p < 0.01, &&&p < 0.001 vs. LPS