Electroacupuncture at ST36 Relieves Visceral Hypersensitivity via the NGF/TrkA/TRPV1 Peripheral Afferent Pathway in a Rodent Model of Post-Inflammation Rectal Hypersensitivity
Received 3 October 2020
Accepted for publication 31 December 2020
Published 5 February 2021 Volume 2021:14 Pages 325—339
Checked for plagiarism Yes
Review by Single anonymous peer review
Peer reviewer comments 2
Editor who approved publication: Professor Ning Quan
Yan Chen, 1, 2 Jiafei Cheng, 1 Yiling Zhang, 1 Jiande DZ Chen, 1, 3 Florin M Seralu 1
1Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 2Division of Gastroenterology, Binzhou Medical University Hospital, Binzhou, Shandong, People’s Republic of China; 3Division of Gastroenterology and Hepatology, University of Michigan, Ann Arbor, MI, USA
Correspondence: Florin M Seralu
Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
Tel/Fax +1 4105023147
Jiande DZ Chen
Division of Gastroenterology and Hepatology, University of Michigan, Ann Arbor, MI, USA
Tel +1 7346475749
Purpose: The aim of the study was to investigate the effects of electroacupuncture (EA) at ST36 on rectal hypersensitivity and compliance in DSS-treated post-inflammation rats. In addition, we explored the involvement of mast cells-triggered NGF/TrkA/TRPV1 peripheral afferent pathway.
Methods: Rats were provided water with 5% dextran sulphate sodium (DSS) for 7 days. Two weeks after the DSS treatment they were subjected to initial and repetitive EA. Different sets of parameters were compared in the initial test and then EA with the selected parameters were performed for 2 weeks. Rectal compliance was assessed by colorectal distension while visceral sensitivity was evaluated by abdominal withdraw reflexes (AWR) and electromyogram (EMG). Masson’s trichrome staining was performed to stain collagen and toluidine blue staining was applied to assess the degranulation of mast cells. Nerve growth factor (NGF), tryptase, TrkA and TRPV1 were measured by Western blot or immunofluorescence staining.
Results: EA at 100 Hz was more effective in improving rectal compliance and visceral hypersensitivity. Daily EA improved visceral hypersensitivity but not rectal compliance. Five weeks after DSS treatment, fibrosis was noted in both sham-EA and EA groups. The expression and activation of mast cells were significantly reduced after the 2-week EA treatment with a concurrent decrease in the expression of colonic NGF/TrkA and TRPV1 in both colon and dorsal root ganglions.
Conclusion: EA at ST36 with a special set of parameters has no effect on reduced rectal compliance but relieves visceral hypersensitivity via the mast cells-triggered NGF/TrkA/TRPV1 peripheral afferent pathway in DSS-treated post-inflammation rats.
Keywords: electroacupuncture, inflammation remission, ulcerative colitis, visceral hypersensitivity, mast cells
Erratum for this paper has been published
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