Inhibition of 5-lipoxygenase and cyclooxygenase-2 pathways by pain-relieving plaster in macrophages

Abstract

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-1β(IL-1β), 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-1β, and PGE2, 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-1β), 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. © 2011 Informa Healthcare USA, Inc.