Fig. 4.

The effect of COX-2 secondary peak on inflammation resolution of the rat ARDS model.(A).SD rats were administered with LPS (3 mg/kg) or the same volume of sterile intravenously, NS-398 (5 mg/kg), or the same volume of 0.9% saline was intravenously administered to SD rats 1 h prior to the LPS stimulation (NS-398 + LPS), administration at 12 h after the LPS challenge (LPS + NS-398), lung sections were collected at 24 h. (B) Representative H&E staining of the lung (original magnification, 200x; inset, 400x). (C) Acute lung injury scores of each group. (D–F) The mRNA expression level of inflammatory cytokines: IL-1β, IL-6, TNF-α. (G and H) Relative expression level of L-PGDS and mPGES-1 protein in the lung was determined by western blot. (I and J) The concentrations of PGE₂ and PGD₂ in lungs were detected by ELISA. Data are presented as mean ± SEM, n = 6. *p < 0.05, **p < 0.01,***p ＜ 0.001,****p < 0.0001.