Is functional state of spinal microglia involved in the anti-allodynic and anti-hyperalgesic effects of electroacupuncture in rat model of monoarthritis?
Spinal microglia play a key role for creating exaggerated pain following tissues inflammation or injury. Electroacupuncture (EA) can effectively control the exaggerated pain both in humans with inflammatory disease and animals with experimental inflammatory pain. However, little is known about the relationship between spinal glial activation and EA analgesia. Using immunohistochemistry, RT-PCR analysis, and behavioral testing, the present study demonstrated that (1) Unilateral intra-articular injection of CFA produced a robust microglial activation and the up-regulation of the tumor necrosis factor (TNF)-alpha, interleukin (IL-1beta), and IL-6 mRNA levels in the spinal cord; (2) Repeated intrathecal (i.t.) injection of minocycline (100 microg), a microglial inhibitor, or EA stimulation of ipsilateral "Huantiao"(GB30) and "Yanglingquan" (GB34) acupoints significantly suppressed CFA-induced nociceptive behavioral hypersensitivity and spinal microglial activation; (3) Combination of EA with minocycline significantly enhanced the inhibitory effects of EA on allodynia and hyperalgesia. For the first time, these data provide direct evidence for the involvement of spinal microglial functional state in anti-nociception of EA. Thus, anti-neuroinflammatory effect of EA might be considered as one of the mechanisms of its anti-arthritic pain effects, and thereby a multidisciplinary integrated approach to treating symptoms related to arthritis might be raised.
Shan
Sun
S
Institute of Neurobiology, Institutes of Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China.
Qi-Liang
Mao-Ying
MY
Hong
Cao
C
Tingting
Li
L
Mei
Han
H
Haili
Pan
P
Yan-Qing
Wang
W
Zhi-Qi
Zhao
Z
Yu-Qiu
Zhang
Z
D000818:Animals; D000843:Ankle Joint / Q000294:innervation / Q000503:physiopathology; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D001169:Arthritis, Experimental / Q000276:immunology* / Q000503:physiopathology / Q000628:therapy*; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D016207:Cytokines / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D004195:Disease Models, Animal; D015671:Electroacupuncture / Q000379:methods*; D005620:Freund's Adjuvant / Q000009:adverse effects; D005911:Gliosis / Q000276:immunology / Q000503:physiopathology / Q000517:prevention & control; D006930:Hyperalgesia / Q000276:immunology* / Q000503:physiopathology / Q000517:prevention & control; D007150:Immunohistochemistry; D008297:Male; D017628:Microglia / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D008911:Minocycline / Q000494:pharmacology / Q000627:therapeutic use; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013116:Spinal Cord / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology
D000900:Anti-Bacterial Agents; D016207:Cytokines; D012333:RNA, Messenger; D005620:Freund's Adjuvant; D008911:Minocycline