The purpose of this study was to examine the beneficial effects of
electroacupuncture (EA) on
neuropathic pain evoked by
spinal cord injury (SCI) and determine the underlying molecular mechanisms of these effects. SCI was induced in rats. Behavioral tests were performed to examine
pain responses induced by mechanical and thermal stimulation. Western blot analysis was used to measure the
protein expression of phosphorylated
mammalian target of rapamycin (p-mTOR), mTOR-mediated phosphorylated
ribosomal protein S6 kinase beta-1 (p-S6K1), and phosphorylated eukaryotic translation
initiation factor 4E-binding
protein 1 (p-4E-BP1) in the superficial dorsal horn of the spinal cord. We showed that SCI increased the expression of p-mTOR, p-S6K1, and p-4E-BP1. The EA intervention attenuated the upregulation of mTOR signaling and alleviated mechanical and thermal
pain responses in SCI rats. Blocking spinal mTOR by
intrathecal injection of
rapamycin also inhibited mechanical and thermal
pain. In addition, blocking spinal phosphorylated phosphatidylinositide 3-kinase (p-PI3K) pathway attenuated p-mTOR pathways and mechanical and
thermal hyperalgesia in SCI rats. EA also decreased the enhanced p-PI3K in the superficial dorsal horn of SCI rats. In conclusion, findings revealed specific signaling pathways that lead to
neuropathic pain in response to SCI, including activation of PI3K-mTOR signaling. Further, results link the beneficial role of EA in alleviating SCI-induced
neuropathic pain to its effect on these molecular mechanisms.