The journal of physiological sciences : JPS
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It has been reported that Toll-like receptor 4 (TLR4), which plays an important role in glial activation in neuropathic pain, is significantly increased in cancer pain. The present study was designed to assess the role of TLR4 in cancer-induced bone pain (CIBP) by intrathecal administration of TLR4 signaling pathway blocker naloxone or lipopolysaccharide Rhodobacter sphaeroides (LPS-RS). ⋯ In contrast, the same pharmacological treatment showed no or slight pain relieving effect at day 16. Our findings demonstrate that the spinal TLR4 signaling pathway contributes to the mechanism underlying CIBP in a stage-dependent manner in rats, and it may be an efficacious target at early stage for the treatment in the future.