Crocin Suppresses LPS-Stimulated Expression of Inducible Nitric Oxide Synthase by Upregulation of Heme Oxygenase-1 via Calcium/Calmodulin-Dependent Protein Kinase 4
Figure 2
Inhibitory effects of crocin on NO production and iNOS expression in LPS-stimulated macrophages. ((a), (b)) RAW 264.7 cells were incubated with the indicated concentrations of crocin for 3 h and then stimulated with LPS (0.1 μg/mL) for 24 h. Next, the supernatant was harvested and the amount of nitrite released from cells was measured by the Griess method (a). versus the group treated with LPS alone (no crocin). Equal amounts of cytosolic extract were analyzed by Western blotting (b). (c) Cells were transfected with HO-1 siRNA or control siRNA. Cells were treated with crocin (500 μM) for 3 h and then were stimulated with LPS (0.1 μg/mL) for 6 h. (d) Cells were incubated with crocin (500 μM) or CoPP (10 μM) for 3 h and then stimulated with LPS (0.1 μg/mL) for 24 h, after which protein levels of iNOS and HO-1 were analyzed by Western blotting. Tubulin was used as a loading control.
