Auricular vagal nerve stimulation ameliorates burn-induced gastric dysmotility via sympathetic-COX-2 pathways in rats.
BACKGROUND
Severe burn injury has been demonstrated to delay gastric emptying. The aim of this study was to investigate effects and cellular mechanisms of auricular electroacupuncture (AEA) at the acupoints innervated by the auricular branch of vagus nerve on burn-induced gastric dysmotility in rats.


METHODS
Propranolol (β-adrenoceptor antagonist) was injected intraperitoneally after the rats underwent burn injury. All experiments were performed 6 h following burn/sham burn injury. AEA was performed at bilateral auricular acupoints for 45 min. Electrocardiogram was recorded for 30 min. Plasma hormones were measured; cyclooxygenase (COX)-2 expressions in gastric tissue were measured using western blotting and real-time RT-PCR.


RESULTS
(i) Burn injury delayed gastric emptying (p = 0.006) and AEA increased gastric emptying by 49% (p = 0.045). (ii) Burn injury evoked a significant elevation in plasma noradrenaline, which was suppressed by AEA. (iii) Burn injury significantly increased protein and mRNA expressions of COX-2 in gastric fundus and antrum. AEA suppressed burn-induced increase in protein expressions, but not mRNA expressions of COX-2.


CONCLUSIONS
Burn injury delays gastric emptying by up-regulating COX-2 attributed to sympathetic overactivity. AEA improves burn-induced delay in gastric emptying, possibly mediated via the sympathetic-COX-2 pathway.
Division of Gastroenterology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA.|Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
H
H
Li
Division of Gastroenterology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA.|Division of Gastroenterology and Hepatology, Johns Hopkins School of Medicine, Baltimore, MD, USA.
J
J
Yin
Division of Gastroenterology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA.
Z
Z
Zhang
Division of Gastroenterology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA.
J H
JH
Winston
Division of Gastroenterology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA.
X-Z
XZ
Shi
Division of Gastroenterology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA.|Division of Gastroenterology and Hepatology, Johns Hopkins School of Medicine, Baltimore, MD, USA.
J D Z
JD
Chen
D020831:Acupuncture, Ear / Q000379:methods; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D002056:Burns / Q000150:complications / Q000235:genetics / Q000628:therapy*; D051546:Cyclooxygenase 2 / Q000235:genetics* / Q000378:metabolism; D015671:Electroacupuncture / Q000379:methods*; D005746:Gastric Emptying / Q000187:drug effects / Q000235:genetics*; D005748:Gastric Fundus / Q000187:drug effects / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism*; D018589:Gastroparesis / Q000209:etiology / Q000235:genetics / Q000628:therapy*; D011433:Propranolol / Q000494:pharmacology; D011706:Pyloric Antrum / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D013270:Stomach / Q000187:drug effects; D015854:Up-Regulation; D055536:Vagus Nerve Stimulation / Q000379:methods*
D000319:Adrenergic beta-Antagonists; D012333:RNA, Messenger; D011433:Propranolol; D051546:Cyclooxygenase 2; C489691:Ptgs2 protein, rat
COX-2; auricular electroacupuncture; autonomic function; gastric emptying; vagal nerve stimulation