Pain
-
Neuropathic pain is one of the most important types of chronic pain. It is caused by neuronal damage. Clinical and experimental studies suggest a critical role for neuroimmune interactions in the development of neuropathic pain. ⋯ The activation of NOD2 signaling in peripheral macrophage mediates the development of neuropathic pain through the production of pronociceptive cytokines (tumor necrosis factor and IL-1β). This study found that peripheral nerve injury promoted a systemic increase in the NOD2 ligand. These results highlight a previously undetermined role for NOD2 signaling in the development of neuropathic pain, suggesting a new potential target for preventing neuropathic pain.
-
Recent studies have suggested a sexually dimorphic role of spinal glial cells in the maintenance of mechanical hypersensitivity in rodent models of chronic pain. We have used the collagen antibody-induced arthritis (CAIA) mouse model to examine differences between males and females in the context of spinal regulation of arthritis-induced pain. We have focused on the late phase of this model when joint inflammation has resolved, but mechanical hypersensitivity persists. ⋯ Taken together, these findings suggest that there are subtle sex differences in microglial expression profiles independent of arthritis. Our experiments failed to identify the underlying mRNA correlates of microglial actions in the late phase of the CAIA model. It is likely that transcriptional changes are either subtle and highly localised and therefore difficult to identify with bulk isolation techniques or that other factors, such as changes in protein expression or epigenetic modifications, are at play.