Expression of COX-2 mRNA in the lung parenchyma as assayed by real-time PCR. The relative mRNA expression ratio in the non-sensitized (and untreated) mice was established as 1.0. COX-2 mRNA expression in the lungs increased 3.6 fold in HDM-sensitized (n = 11) versus non-sensitized mice (n = 5). Baseline levels of COX-2 mRNA in the lungs were higher in non-sensitized mice under both PGE2 (n = 5) and sulprostone (n = 5) when compared to levels in non-sensitized and non-treated animals. COX-2 expression in PGE2 (n = 11) and sulprostone-treated mice (n = 11) increased by 2.5 and 3.8 fold, respectively, when the animals were exposed to HDM (*p < 0.05, **p < 0.01, ***p < 0.005).