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Electroacupuncture reduces the expression of proinflammatory cytokines in inflamed skin tissues through activation of cannabinoid CB 2 receptors
Author(s) -
Su T.F.,
Zhao Y.Q.,
Zhang L.H.,
Peng M.,
Wu C.H.,
Pei L.,
Tian B.,
Zhang J.,
Shi J.,
Pan H.L.,
Li M.
Publication year - 2012
Publication title -
european journal of pain
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.305
H-Index - 109
eISSN - 1532-2149
pISSN - 1090-3801
DOI - 10.1002/j.1532-2149.2011.00055.x
Subject(s) - proinflammatory cytokine , cannabinoid receptor type 2 , hyperalgesia , electroacupuncture , pharmacology , am251 , cannabinoid , allodynia , inflammation , tumor necrosis factor alpha , chemistry , cannabinoid receptor , receptor , nociception , cytokine , medicine , agonist , immunology , acupuncture , pathology , alternative medicine
Endogenous cannabinoids and peripheral cannabinoid CB2 receptors ( CB2Rs ) are involved in the antinociceptive effect of electroacupuncture ( EA ) on inflammatory pain. However, it is not clear how CB2R activation contributes to the antinociceptive effect of EA . The major proinflammatory cytokines, such as tumour necrosis factor‐α ( TNF ‐α), interleukin‐1β ( IL ‐1β) and IL ‐6, are involved in inflammatory pain. Here we determined the effects of CB2R activation and EA on the expression level of IL ‐1β, IL ‐6 and TNF ‐α in inflamed skin tissues. Inflammatory pain was induced by injection of complete F reund's adjuvant into the left hindpaw of rats. Thermal hyperalgesia was tested with a radiant heat stimulus, and mechanical allodynia was quantified using von F rey filaments. The mRNA and protein levels of IL ‐1β, IL ‐6 and TNF ‐α in inflamed skin tissues were measured using real‐time polymerase chain reaction and W estern blot, respectively. Local injection of the selective CB2R agonist AM1241 or EA applied to GB30 and GB34 significantly reduced thermal hyperalgesia and mechanical allodynia induced by tissue inflammation. The specific CB2R antagonist AM630 significantly attenuated the antinociceptive effect of EA . Furthermore, EA or AM1241 treatment significantly decreased the mRNA and protein levels of IL ‐1β, IL ‐6 and TNF ‐α in inflamed skin tissues. In addition, pretreatment with AM630 significantly reversed the inhibitory effect of EA on these cytokine levels in inflamed skin tissues. Our results suggest that EA reduces inflammatory pain and proinflammatory cytokines in inflamed skin tissues through activation of CB2Rs .