title: [Electroacupuncture Intervention Enhances Splenic Natural Killer Cell Activity via Inhibiting Phosphorylation of ERK 5 in the Hypothalamus of Surgically Traumatized Rats].
abstract: OBJECTIVE
  To observe the effect of electroacupuncture (EA) on cytotoxic activity of splenic natural killer (NK) cells after surgical trauma via extracellular signal-regulated kinase (ERK) 5 pathway in the rats' hypothalamus, so as to explore its mechanism underlying improving immune disorders after surgery.
  
  
  METHODS
  Sprague-Dawley rats were randomly divided into the following 6 groups: control, trauma model, EA, sham EA, 4 nmol-BIX 02188 (an inhibitor for ERK 5 catalytic activity) and 20 nmol-BIX 02188 (n = 6 rats per group). The surgical trauma model was established by making a longitudinal incision (6 cm in length) along the median line of the back to expose the spinal column and another longitudinal incision along the abdominal median line. EA (2 Hz/15 Hz, 1 - 2 mA) was applied to bilateral "Zusanli" (ST 36) for 30 min immediately after surgery. For rats of the BIX groups, intra-lateral ventricular microinjection of BIX 02188 (10 µL, 4 nmol or 20 nmol, or saline for control rats) was conducted 30 min before the surgery. The expression level and protein of phosphorylated ERK 5 (p-ERK 5) and corticotropin-releasing factor (CRF) protein were measured by immunohistochemistry and Western blot, respectively. The cytotoxicity of splenic NK cells and the expression of splenic Perforin and Granzyme-B genes were measured by lactate dehydrogenase (LDH) release assay and real-time PCR, respectively.
  
  
  RESULTS
  In comparison with the control group, hypothalamic p-ERK 5 immunoactivity, p-ERK 5 protein and CRF protein expression levels were significantly up-regulated in the model group (P<0. 01, P<0. 05), while splenic NK cell cytotoxicity and Perforin mRNA and Granzyme-B mRNA expression levels were notably down-regulated in the model group (P <0. 05, P < 0. 01). Following EA and administration of ERK 5 antagonist, the increased expression levels of p-ERK 5 immunoactivity in the EA group, and p-ERK 5 and CRF proteins in both EA and 20 nmol-BIX 02188 groups were obviously down-regulated (P<0. 05, P<0. 01), without changes in the sham EA and 4 nmol-BIX 02188 groups (P>0. 05) except the increased p-ERK 5 protein in the 4 nmol-BIX 02188 group. In addition, the down-regulated NK cell activity, Perforin mRNA and Granzyme-B mRNA expression levels were significantly reversed in the EA and 20 nmol-BIX 02188 groups (P<0. 05, P<0. 01). No significant differences were found between the EA group and 20 nmol-BIX 02188 group in down-regulating hypothalamic p-ERK 5 and CRF protein expression and up-regulating splenic NK cytotoxicity and Perforin and Granzyme-B gene expression (P>0. 05).
  
  
  CONCLUSIONS
  EA can promote the cytotoxicity of splenic NK cells in surgical trauma rats, which may be closely associated with its functions in down-regulating trauma-induced activation of ERK 5 pathway and production of CRF in the hypothalamus.
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Ke-ying
authors.initials: KY
authors.lastname: Zhu
authors.forename: Sheng
authors.initials: S
authors.lastname: Xiao
authors.forename: Yan-qing
authors.initials: YQ
authors.lastname: Wang
authors.forename: Gen-cheng
authors.initials: GC
authors.lastname: Wu
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
mesh_terms: D015669:Acupuncture Points; D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism; D015671:Electroacupuncture; D006801:Humans; D007031:Hypothalamus / Q000201:enzymology* / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology*; D008297:Male; D048054:Mitogen-Activated Protein Kinase 7 / Q000276:immunology* / Q000378:metabolism; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013154:Spleen / Q000166:cytology* / Q000276:immunology; D014947:Wounds and Injuries / Q000276:immunology* / Q000601:surgery / Q000628:therapy*
chemical_list: D003346:Corticotropin-Releasing Hormone; D048054:Mitogen-Activated Protein Kinase 7