Bee venom and melittin reduce proinflammatory mediators in lipopolysaccharide-stimulated BV2 microglia

Bee venom (BV), well known as a traditional Oriental medicine, has been shown to exhibit anti-arthritic and anti-carcinogenic effects. However, the molecular mechanisms responsible for the anti-inflammatory activity of BV have not been elucidated in microglia. In the present study, we investigated the anti-inflammatory effect of BV and its major component, melittin (MEL), on lipopolysaccharide (LPS)-stimulated BV2 microglia. Our results indicate that BV and MEL suppress LPS-induced nitric oxide (NO) and inducible NO synthase (iNOS) expression in a dose-dependent manner, without causing cytotoxicity in BV2 microglia. Moreover, BV and MEL suppressed LPS-induced activation of nuclear factor kappa B (NF-kappaB) by blocking degradation of IkappaBalpha and phosphorylation of c-Jun N-terminal kinase (JNK) and Akt, which resulted in inhibition of iNOS expression. Our data also indicate that BV and MEL exert anti-inflammatory effects by suppressing the transcription of cyclooxygenase (COX)-2 genes and proinflammatory cytokines, such as interleukin (IL)-1beta, IL-6 and tumor necrosis factor (TNF)-alpha. BV and MEL also attenuated the production of prostaglandin E(2) (PGE(2)). These results demonstrate that BV and MEL possess a potent suppressive effect on proinflammatory responses of BV2 microglia and suggest that these compounds may offer substantial therapeutic potential for treatment of neurodegenerative diseases that are accompanied by microglial activation.