ABSTRACT
<p><b>OBJECTIVE</b>To investigate the analgesic effect of interleukin-2 (IL-2) in mice with spared nerve injury (SNI).</p><p><b>METHOD</b>IL-2 was intraperitoneally injected in mice with induced SNI, and von Frey Filaments test and cold plate test were carried out to accesses the analgesic effects of IL-2 and the effect of naloxone in antagonizing the effects of IL-2.</p><p><b>RESULTS</b>IL-2 produced analgesic effects against hyperalgesia and allodynia in mouse models of SNI, and the effect of IL-2 lasted for more than 24 h, showing a double-peak pattern in its action with the two peaks occurring at 30 and 105 min, respectively. The effect of IL-2 could be significantly antagonized by naloxone.</p><p><b>CONCLUSIONS</b>IL-2 has long-lasting analgesic effects in mouse models of SNI model, showing a double-peak pattern of its action. The analgesic effect of IL-2 is probably mediated by opiate receptor.</p>