Ancient Chinese medicine and mechanistic evidence of acupuncture physiology

Abstract

Acupuncture has been widely used in China for three millennia as an art of healing. Yet, its physiology is not yet understood. The current interest in acupuncture started in 1971. Soon afterward, extensive research led to the concept of neural signaling with possible involvement of opioid peptides, glutamate, adenosine and identifying responsive parts in the central nervous system. In the last decade scientists began investigating the subject with anatomical and molecular imaging. It was found that mechanical movements of the needle, ignored in the past, appear to be central to the method and intracellular calcium ions may play a pivotal role. In this review, we trace the technique of clinical treatment from the first written record about 2,200 years ago to the modern time. The ancient texts have been used to introduce the concepts of yin, yang, qi, de qi, and meridians, the traditional foundation of acupuncture. We explore the sequence of the physiological process, from the turning of the needle, the mechanical wave activation of calcium ion channel to beta-endorphin secretion. By using modern terminology to re-interpret the ancient texts, we have found that the 2nd century B.C.: physiologists were meticulous investigators and their explanation fits well with the mechanistic model derived from magnetic resonance imaging (MRI) and confocal microscopy. In conclusion, the ancient model appears to have withstood the test of time surprisingly well confirming the popular axiom that the old wine is better than the new.

Fig. 1

a Acupuncture at GB35. b MRI and magnetic resonance elastography (MRE) imaging of mechanical waves in soleus muscle: (A and B) T1 images showing slice orientation; (C) T1 image of the soleus muscle; (D) MRE wave image in the soleus muscle

Fig. 2

a Line profile of damped sinusoid in longitudinal and transverse directions at acupoint GB35. The driver frequency is at 100 Hz. b Artist’s rendering of the 3D acoustic shear wave along the jin-luo structure in the soleus muscle derived from the envelopes of the modulated waves. c, d Repeat of a and b for sham point 1 cm left of GB35

Fig. 3

Intracellular calcium waves in fibroblast (NIH3T3) cells: latency and wave amplitude distributions in two dimensions. Initial spreading velocity is slightly more than 50 μm/s and quickly settled down to 5.5 μm/s within a few seconds. The diagonal spacing is 1.5 cm (with permission from Li et al. [24])