Acupuncture and Meridian Science Research Center, College of Korean Medicine, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea.
Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, 60611, USA.
BMC Complement Altern Med. 2017 Jan 3;17(1):1. doi: 10.1186/s12906-016-1505-2.
Biomechanical 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.
In 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.
It 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.
Surface 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.
通过结缔组织的缠绕产生的一种称为“针抓”的生物力学现象被认为是针刺操作的作用机制。本研究旨在验证针刺抓握力是否会影响针刺在尾部闪烁潜伏期（TFL）和大鼠足底福尔马林测试中的镇痛作用。
为了在针灸针表面上产生不同的粗糙度，使用碳化硅砂纸（粒度分别为 600（轻度粗）和 200（特粗））对直径为 0.2 毫米的针灸针进行划痕。然后，使用原子力显微镜和 Acusensor®分别测量划痕针的表面粗糙度和旋转引起的扭矩。在对各种粗糙度的针进行 5 次单向旋转后，切除包括针灸针插入部位在内的大鼠腹壁组织，并使用苏木精和伊红（H-E）染色分析结缔组织的形态变化。最后，在大鼠 TFL 和福尔马林测试中测试了粗针表面对捻转操作引起的抗伤害作用的影响。
观察到，针表面越粗糙，在旋转时，针抓力和皮下结缔组织的厚度就越强。针刺大鼠腿部足三里（ST36）穴位 10 分钟后，针的表面越粗糙，TFL 增加的比例越大。在大鼠福尔马林测试中，与非打磨正常针相比，更粗糙的针在早期和晚期阶段都能显著发挥更大的镇痛作用。
针灸针的表面粗糙度增强了针刺疗法在大鼠中的镇痛作用，这部分支持了针刺操作中通过结缔组织进行的机械信号理论。
