Oridonin inhibits LPS-induced inflammation in human gingival fibroblasts by activating PPARγ

Oridonin, the major terpene isolated from Rabdosia rubescens, has been used as dietary supplement. Recently, it has been known to exhibit anti-inflammatory effect. This study we employed an in vitro model of LPS-stimulated human gingival fibroblasts to investigate the anti-inflammatory effects and mechanism of oridonin. Oridonin (10-30 mu g/mL) was administrated 1 h before LPS treatment. The results showed that oridonin significantly inhibited inflammatory mediators PGE(2), NO, IL-6, and IL-8 production. Immunoblotting experiments revealed that oridonin reduced the expression of phosphorylation levels of NF-kappa B p65 and I kappa B alpha. Furthermore, the expression of PPAR gamma was up-regulated by the treatment of oridonin. Further studies showed that PPAR gamma inhibitor GW9662 could reverse the inhibition of oridonin on PGE(2), NO, IL-6, and IL-8 production. In conclusion, oridonin inhibited LPS-induced microglia activation through activating PPAR gamma.