ABSTRACT
@#【Objective】To unmask the mechanisms underlying the suppression of infant neuropathic pain after peripheral nerve injury.【Methods】Rats were subjected to spared nerve injury(SNI)at postnatal 10 d or 33 d. Mechanical paw withdrawal thresholds as well as spinal interleukin-10(IL-10)and the β-endorphin precursor gene proopiomelanocortin(POMC)mRNA expression were detected 7 d after surgery. The IL-10 or β-endorphin neutralizing antibody was intrathecally injected for 3 d(the 7 th-9 th day after surgery)and mechanical paw withdrawal thresholds were tested 1 h after each injection. Spinal IL-10 mRNA and POMC mRNA were detected by RT-qPCR.【Results】In contrast to adult rats,infant rats subjected to SNI displayed no mechanical allodynia but an increase in spinal cord IL-10 and POMC mRNA expression. Intrathecal administration of the IL-10 antibody and β-endorphin antibody evoked neuropathic painlike behaviors in infant rats. SNI-induced POMC mRNA increase was blocked by the pretreatment with intrathecal the IL-10 antibody,while the increased IL-10 mRNA expression was not affected by the β-endorphin antibody pretreatment.【Conclusions】The suppression of neuropathic pain in infant rats may be mediated by activation of spinal IL-10/β-endorphin pathway.