Inducible expression of NOS and COX-2 in evaluating the effects of Ruyi-Jinhuang Gao on somatic pain - Associated inflammation

Ruyi-Jinhuang Gao (RJG) is an ointment prepared from Ruyi-Jinhuang San (RJS), a traditional formula of powder-type Chinese medicine, usually used in anti-inflammatory analgesic care in China. The present study is aimed to detect the anti-inflammatory signaling of RJG exposed by an experimental model of lipopolysaccharides (LPS)-induced pro-inflammatory expression of inducible nitric oxide synthase (iNOS) and prostaglandin endoperoxide synthase (PGH synthase-2, COX-2). LPS-induced activation of iNOS and COX-2 has been recognized to increase cytokines and nitric oxide (NO), which play predominant roles in inflammation. In the culture of RAW264.7 cells, RJG concentration-dependently inhibited LPS-induced iNOS and COX-2 expression. However, the herbal components of RJG displayed different results, including increase and decrease of both protein expressions. Among them, inhibition by Curcuma Zedorarica Rhizoma (Cu), Atractylodis Lancea Rhizoma (At), and Glycyrrhizae Radix (Gl) are more potent than that by others. Inhibition by Cu and At are associated with their cytotoxicity. Glycyrrhizae Radix (Gl), with lower cytotoxicity in comparison with Cu and At, is the most potent component of RJG on inhibiting LPS-induced iNOS and COX-2 expression. In comparison with LPS-induced tumor necrosis factor-α (TNF-α), croton oil-induced formation of TNF-α and interleukin-4 (IL-4), RJG did not increase the pro-inflammatory cytokines. These facts indicated that RJG could not significantly sensitize an immunologic response during the treatment of non-wounded inflammation on body surface. Ruyi-Jinhuang Patch (RJP), a pharmaceutical preparation of RJG, has proven to have significant relief of cutaneous inflammation-associated somatic pain in clinical use.