Fig. 6

Spinal IL-1β is necessary for PAE induced allodynia following minor CCI. A separate group of PAE rats were used to determine whether IL-1β is necessary for induction of allodynia following minor CCI. PAE rats with minor CCI receive either i.t. IL-1 receptor antagonist (IL-1RA) or vehicle and (panel a) ipsilateral and (panel b) contralateral hindpaw responses are assessed. Prior to surgery, no hindpaw response threshold differences are observed between vehicle and IL-1RA groups. Following minor CCI and prior to injection, similar levels of robust ipsilateral allodynia is observed in both groups, while contralateral hindpaw responses remain unchanged. PAE rats receiving IL-1RA reveal ipsilateral reversal from allodynia by 1 h that persisted throughout the 3 h time-course compared to vehicle injected rats. By 24 h post-injection, all rats demonstrate full ipsilateral allodynia, with no significant differences observed between groups. “1-sut CCI” = “minor CCI”. N = 7 rats per group. Asterisks indicate p < 0.05