RESUMO
CONTEXT: Pain-relieving plaster (PRP) is a traditional Chinese medicine (TCM) that has been widely used with satisfactory results in the treatment of some diseases related to inflammation, such as bruises, chronic arthritis. OBJECTIVE: The mechanisms underlying the anti-inflammatory actions of PRP are investigated in this study for the first time. MATERIALS AND METHODS: The anti-inflammatory effects of PRP extracts were evaluated in lipopolysaccharide (LPS) or calcium ionophore A23187-treated murine peritoneal macrophages (PMs). Tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), prostaglandin E2 (PGE2), and leukotrienes B4 (LTB4) were evaluated by ELISA assays. Reverse transcriptase-polymerase chain reaction (RT-PCR) and western blot analysis were used to detect the expression of cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX). Nuclear factor-kappa B (NF-κB)-DNA-binding activity was determined by gel mobility shift assay. RESULTS: PRP extracts were found to inhibit the production of TNF-α, IL-1ß, and PGE(2), reduce the expressions of COX-2 at the mRNA and protein levels induced by LPS, and reduced the production of LTB4 induced by A23187. Furthermore, PRP extracts significantly attenuated LPS-induced NF-κB-DNA-binding activity. DISCUSSION AND CONCLUSION: The anti-inflammatory effects of PRP possibly are related to reduction of inflammatory cytokines (TNF-α and IL-1ß), inducible inflammatory enzyme (COX-2), and its metabolite PGE2 via NF-κB signal pathway. Moreover, PRP extracts also notably inhibited the production of LTB4, indicating that PRP inhibited the 5-LOX pathway, which may be the other mechanism for its anti-inflammatory action.
