The cumulative analgesic effect of repeated electroacupuncture involves synaptic remodeling in the hippocampal CA3 region

Qiuling Xu; Tao Liu; Shuping Chen; Yonghui Gao; Junying Wang; Lina Qiao; Junling Liu

doi:10.3969/j.issn.1673-5374.2012.18.003

The cumulative analgesic effect of repeated electroacupuncture involves synaptic remodeling in the hippocampal CA3 region

Neural Regen Res. 2012 Jun 25;7(18):1378-85. doi: 10.3969/j.issn.1673-5374.2012.18.003.

Authors

Qiuling Xu¹, Tao Liu¹, Shuping Chen², Yonghui Gao², Junying Wang², Lina Qiao², Junling Liu²

Affiliations

¹ Hainan Medical University, Haikou 571101, Hainan Province, China.
² Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China.

PMID: 25657670
PMCID: PMC4308787
DOI: 10.3969/j.issn.1673-5374.2012.18.003

Abstract

In the present study, we examined the analgesic effect of repeated electroacupuncture at bilateral Zusanli (ST36) and Yanglingquan (GB34) once a day for 14 consecutive days in a rat model of chronic sciatic nerve constriction injury-induced neuropathic pain. In addition, concomitant changes in calcium/calmodulin-dependent protein kinase II expression and synaptic ultrastructure of neurons in the hippocampal CA3 region were examined. The thermal pain threshold (paw withdrawal latency) was increased significantly in both groups at 2 weeks after electroacupuncture intervention compared with 2 days of electroacupuncture. In ovariectomized rats with chronic constriction injury, the analgesic effect was significantly reduced. Electroacupuncture for 2 weeks significantly diminished the injury-induced increase in synaptic cleft width and thinning of the postsynaptic density, and it significantly suppressed the down-regulation of intracellular calcium/calmodulin-dependent protein kinase II expression in the hippocampal CA3 region. Repeated electroacupuncture intervention had a cumulative analgesic effect on injury-induced neuropathic pain reactions, and it led to synaptic remodeling of hippocampal neurons and upregulated calcium/calmodulin-dependent protein kinase II expression in the hippocampal CA3 region.

Keywords: acupuncture analgesia; calcium/calmodulin-dependent protein kinase II; chronic neuropathic pain; cumulative effect; electroacupuncture; hippocampal CA3 region; neural regeneration; neurobiology; synaptic plasticity.