The effect of electroacupuncture on regulating pain and depression-like behaviors induced by chronic neuropathic pain

Background: Recently, the role of electroacupuncture (EA) in chronic neuropathic pain has been widely reported. However, its specific mechanisms and ability to mitigate depression-like behaviors induced by chronic pain remains unclear. This study aims to determine the analgesic and antidepressant effect of EA. Methods: The mechanical threshold sensory and hot plate tests were employed to measure mechanical hyperalgesia and thermal allodynia. The open filed test (OFT) and tail suspension test (TST) were used to observe depressive behavior in chronic constrictive injury (CCI) mice. In addition, the 5-hydroxytryptamine (5-HT) and brain-derived neuropathic factor (BDNF) levels in the anterior cingulate cortex (ACC) and spinal cord were assessed using enzyme-linked immunosorbent assay (ELISA). The protein levels of cAMP-response element-binding protein (CREB) and BDNF in the ACC were analyzed by western blotting. Results: Our results demonstrated that EA treatment could increase the mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) values. Also, EA improved the CCI-induced depression-like behaviors, and significantly reversed the down-regulation of BDNF and 5-HT expression in the ACC and spinal cord after CCI. Furthermore, EA regulated the level of CREB in the ACCs and spinal cords of mice. Conclusions: These results suggested that the analgesic and antidepressant effect of EA is achieved through regulating CREB-5-HT/BDNF signaling pathway in the ACCs and spinal cords of mice.