Abstract
BackgroundBiomechanical phenomenon called “needle grasp” through the winding of connective tissue has been proposed as an action mechanism of acupuncture manipulation. The aim of the present study is to verify whether the needle grasp force affects the pain-relieving activity of acupuncture in the tail-flick latency (TFL) and the rat paw formalin tests.MethodsIn order to make different roughness on the acupuncture needle surface, the needles with 0.2 mm-diameter were scratched using silicon carbide sandpapers with the grit numbers of 600 (mild coarse) and 200 (extra coarse). The surface roughness and rotation-induced torque of the scratched needles were then measured by atomic force microscope and Acusensor®, respectively. Rat abdominal wall tissues including insertion site of acupuncture needle were excised after 5 unidirectional rotations of the needles having various degrees of roughness, and the morphological changes of connective tissues were analyzed using hematoxylin and eosin (H-E) staining. Finally, the effects of coarse needle surface on anti-nociception induced by twirling manipulation were tested in rat TFL and formalin test.ResultsIt was observed that the rougher the needle surface, the stronger the needle grasp force and thickness of subcutaneous connective tissue while rotating. TFL increased in proportion to surface roughness of the ground needles 10 min after acupuncture into the Zusanli acupoint (ST36) on rat’s legs. In the rat formalin test, the rougher needle also significantly exerted the larger analgesic effect during both early and late phases compared to non-ground normal needle.ConclusionSurface roughness of the acupuncture needle enhanced an anti-nociceptive activity of acupuncture therapy in rats, which partially supports the mechanical signaling theory through connective tissues in acupuncture manipulation.
Highlights
Biomechanical phenomenon called “needle grasp” through the winding of connective tissue has been proposed as an action mechanism of acupuncture manipulation
Whereas the importance of grasp force by winding connective tissues was elucidated by showing the morphological changes of tissues or neighboring cells around the pricking point of acupuncture manipulation in an ex vivo system, there have been no reports precisely explaining how the friction-induced grasp force between the needle surface and the contacting tissues correlates with alleviating the symptoms of diseases
In case of deeply scraped needle, arrangements of various cells and Analgesic effect of twirling manipulation of scratched acupuncture needle in tail flick latency and formalin test After confirming the proportional increase of grasp force depending on surface roughness of the acupuncture needle, we subsequently investigated whether the strength of needle grasp force can affect the analgesic effect of acupuncture manipulation using tail-flick latency (TFL) and the rat paw formalin tests in the rats
Summary
Biomechanical phenomenon called “needle grasp” through the winding of connective tissue has been proposed as an action mechanism of acupuncture manipulation. Langevin et al have previously hypothesized that a different and novel mechanism for needle grasp might involve the contraction of connective tissue, and proposed that the winding connective tissue during needle rotation creates a tight mechanical coupling between needle and tissue, which might allow needle manipulation to deliver a powerful mechanical signal into the tissue [10]. This hypothesis was supported by histological observations in rat tissue explants that showed marked thickening of subcutaneous tissue and a whorl of dense connective tissue around the rotated needle [10]. Whereas the importance of grasp force by winding connective tissues was elucidated by showing the morphological changes of tissues or neighboring cells around the pricking point of acupuncture manipulation in an ex vivo system, there have been no reports precisely explaining how the friction-induced grasp force between the needle surface and the contacting tissues correlates with alleviating the symptoms of diseases
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
