NK cells mediate the cumulative analgesic effect of electroacupuncture in a rat model of neuropathic pain

BMC Complementary and Alternative Medicine

Research Article

Shu-Ping Chen¹  Yong-Hui Gao¹  Lian-Hong Tan¹  Li-Na Qiao¹  Jun-Ying Wang¹  Jun-Ling Liu¹  Qiu-Ling Xu² 

[1] Department of Physiology, Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, 100700, Beijing, China;Hainan Medical University, 571101, Haikou, Hainan Province, China;

关键词: Acupuncture analgesia;    Cumulative effect;    Chronic constriction injury;    Innate immunity;    Acquired immunity;    NK cells;   

DOI  :  10.1186/1472-6882-14-316

 received in 2013-12-20, accepted in 2014-08-13,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundCumulating evidence has revealed the effectiveness of acupuncture therapy in relieving pain via immunoregulation. However, its underlying mechanism remains unknown. The present study was designed to determine the changes of immunogenic responses at different time-points of electroacupuncture (EA) interventions in neuropathic pain rats.MethodsThe neuropathic pain model was established by ligature of the left sciatic nerve to induce chronic constriction injury (CCI). EA was applied at Zusanli (ST36) and Yanglingquan (GB34) for the EA groups. The thermal pain threshold was detected with an algesia-detector. The subgroups of plasma and splenic lymphocytes were determined via fluorescence-activated cell sorting. Specific inflammatory cytokines were assayed using an ELISA-based bead multiplex assay. The activities of splenic natural killer (NK) cells and cytotoxic T lymphocytes were detected by methyl thiazolyl tetrazolium colorimetric method. For confirming the involvement of NK cell in EA-analgesia, anti-asialo-ganglio-N-tetraosylceramide (anti-asialo-GM1) antibody was given to CCI rats before EA.ResultsFollowing CCI, the thermal pain threshold of the affected hind footpad was significantly decreased, and increased from the 3rd day to the 12th day after EA interventions, presenting a time-dependent tendency from the 5th day on. From day 3 to 5 of EA interventions, the percentages and activity of splenic NK cells, concentrations of splenic interleukin-2 (IL-2) and beta-endorphin (β-EP) were significantly increased. Meanwhile, the concentrations of plasma IL-2, IL-1β and gamma-interferon (IFN-γ) were significantly decreased and returned to the normal level on day 12 following EA. Plasma transforming growth factor-β (TGF-β) levels were considerably upregulated on day 5 and 12 following EA. The CD4+/CD8+ T cell ratio was markedly downregulated compared with the control and CCI groups on day 5 and returned to the normal level on day 12 following EA. After depleting NK cells by anti-asialo-GM1 antibody, the increased thermal pain threshold following EA intervention was obviously reduced.ConclusionsRepeated EA interventions have a time-dependent cumulative analgesic effect in neuropathic pain rats, which is closely associated with its regulatory effects on NK cells, splenic IL-2, β-EP, and plasma IL-2, IL-1β, IFN-γ and TGF-β levels.

【 授权许可】

Unknown   
© Gao et al.; licensee BioMed Central Ltd. 2014. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.