Inhibitory Effects of Salidroside on Nitric Oxide and Prostaglandin E2 Production in Lipopolysaccharide-Stimulated RAW 264.7 Macrophages

The aim of this study was to evaluate the effect of salidroside on lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E-2 (PGE(2)) production in RAW 264.7 macrophages and related anti-inflammatory mechanism. PGE(2) production was measured by enzyme-linked immunosorbent assay (ELISA); NO production was tested by Griess reagent. Inducible nitric oxidesynthase (iNOS) and COX-2 were determined by RT-PCR and Western blot analysis; IB and P-IB protein express were detected by Western blot analysis; cytosolic free Ca2+ ([Ca2+]i)was measured by a fluorescent microscope. The data showed salidroside inhibited LPS-induced NO and PGE(2) production and reduced iNOS and COX-2 protein expression in RAW 264.7 macrophages. Consistent with these observations, salidroside inhibited LPS-induced cytosolic free Ca2+ concentration ([Ca2+]i) elevation. In addition, we further investigated signal transduction mechanisms and found that the activation of NF-B was suppressed by salidroside in a dose-dependent manner. These results suggest that salidroside suppresses NO and PGE(2) production by inhibiting iNOS and COX-2 protein expression, level of [Ca2+]i, and activation of NF-B signal transduction pathway.