Figure 1.

Lipopolysaccharide (LPS) induced cyclooxygenase-2 (COX-2) and cytosolic phospholipase A₂ (cPLA₂) expression and prostaglandin E₂ (PGE₂) synthesis in human tracheal smooth muscle cells (HTSMCs). (A) HTSMCs were incubated with 100 µg·mL⁻¹ of LPS for the indicated time intervals. COX-2 and cPLA₂ protein expression were determined by Western blot analysis. (B) For mRNA expression, HTSMCs were incubated with LPS (100 µg·mL⁻¹) for the indicated time intervals. mRNA was extracted and analysed by RT-PCR. (C) HTSMCs were transiently transfected with either cPLA₂-luc or COX-2-luc reporter gene together with β-galactosidase plasmid and then incubated with 100 µg·mL⁻¹ of LPS for the indicated time intervals. Luciferase activity was determined and normalized with β-galactosidase activity. (D) HTSMCs were pretreated without or with NS-398 (10 µM) or celecoxib (CLC; 10 µM) for 1 h and then incubated with LPS for the indicated time intervals or 6 h respectively. The culture supernatants were collected to measure PGE₂ concentration. The basal level of PGE₂ was approximately 256 pg·mL⁻¹. Data are expressed as mean ± SEM of five independent experiments (n = 5). *P < 0.05, #P < 0.01 as compared with the cells exposed to vehicle alone.