The analgesic effects of anti-inflammatory cytokines derived from M2 cells in response to a PPAR-γ agonist or IL-4 application have been suggested by showing a correlation between the attenuation of pain and enhanced mRNA levels of IL-10 in postoperative and neuropathic pain models; the direct contribution of IL-10, however, has not been examined [22, 27, 28]. Here, IL4 is linked to neuropathic pain.