Anti-nociceptive effects of Tanshinone IIA (TIIA) in a rat model of complete Freund's adjuvant (CFA)-induced inflammatory pain

Background: Inflammatory pain is an important clinical symptom. The levels of extracellular signal-regulated kinases (ERKs) and the levels of cytokines such as interleukin 1 beta (IL-1 beta). interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) play important roles in inflammatory pain. Tanshinone IIA (TIIA) is an important component of Danshen, a traditional Chinese medicine that has been commonly used to treat cardiovascular disease. In this study, we investigated the potential anti-inflammatory nociceptive effects of TIIA on complete Freund's adjuvant (CFA)-induced inflammation and inflammatory pain in rats. Methods: The effects of TIIA on CFA-induced thermal and mechanical hypersensitivity were investigated using behavioral tests. The levels of ERKs, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappa B) and transient receptor potential vanilloid 1 (TRPV1) in the fifth segment of the lumbar spinal cord (13) ganglia were detected by Western blot, and the levels of mRNA and protein production of IL1-beta, IL-6 and TNF-alpha were detected by real-time reverse transcription polymerase chain reaction (RT-PCR) and enzyme-linked immuno sorbent assay (ELISA). Results: In this study, we found that TIIA attenuates the development of CFA-induced mechanical and thermal hypersensitivity. In addition, p-ERK and NF-kappa B expression levels were inhibited by TIIA, and the levels of the pro-inflammatory cytokines IL-1 beta, IL-6 and TNF-alpha were reduced. Finally, we found that the expression level of TRPV1 was significantly decreased after TIIA injection. Conclusions: This study demonstrated that TIIA has significant anti-nociceptive effects in a rat model of CFA-induced inflammatory pain. TIIA can inhibit the activation of ERK signaling pathways and the expression of pro-inflammatory cytokines. These results suggest that TIIA may be a potential anti-inflammatory and anti-nociceptive drug. (C) 2012 Elsevier Inc. All rights reserved.