Function of Collagen and Mast Cells in Acupuncture Points

Abstract

The acupoint is the responsive point that is stimulated during acupuncture treatment, and its structural basis and action mechanism have been largely elucidated by researchers. Clinical medical imaging and extensive studies on anatomy have indicated that the structural and functional basis for the human body’s meridians and acupoints is a complex system that primarily comprises connective tissues with numerous intertwining blood vessels, nerves, collagen fibers, and mast cells. Nevertheless, how the effective acupunctural signals transmit through acupoints to induce analgesia through a series of biochemical reactions along the meridians is a mystery. We have applied different acupuncture methods combined with morphology observations, mechanical signal detection, and animal pain threshold measurements to analyze the correlation between acupuncture analgesia and collagen fiber mechanical deformation as well as mast cell degranulation at acupoints. Furthermore, to explore the structural and functional basis of acupoints and the initiation of acupunctural signals, the patch clamp technique was used to investigate the dynamic characteristics of mechanosensitive proteins in relation to acupuncture at the cellular level. The results indicated that acupuncture analgesia was induced by physical stimulation at acupoints, where collagen fibers were deformed by stress and the surrounding mast cells were activated. The acupoint response is based on the spatial conformations of the blood vessels–mast cells–nerves. Once activated, mast cells are degranulated and release several types of bioactive substances, which increase blood vessel permeability. In addition, they act on the surrounding peripheral nerve endings, which induce a local peripheral nerve impulse and then transfer the acupunctural signal to the central nervous system. During this process, a positive feedback signal is generated by neurotransmitters acting on the mast cells and distributed along the meridians. An analgesic effect is produced and transmitted through an indirect effect on the organs and tissues along the meridians.