Clarification of acupoint essence is a core prerequisite for elucidating the mechanisms of acupuncture, yet the structural form of acupoints has not been fully clarified over the long term. Current research suggests that acupoint essence is related to specific structural systems, such as nerves, circulation, immunity, or fascia; however, these perspectives are not easily integrated. According to traditional Chinese medicine (TCM), acupoints along meridians are special locations of the human body where “qi” and “xue” flow in and out. Based on the novel concept that “Telocyte (TC) is a potential meridian parenchymal cell”, this study further investigated the role of TCs and their associated structures within acupoint regions, so as to provide new experimental evidence for elucidating the material basis of acupoints and revealing the principles underlying acupuncture effects.

The aim of this study was to clarify, using electron microscopy, the interactions between TCs and their elongated protrusion (telopode, Tp) within acupoint regions and various surrounding structural components, and to investigate whether specialized ultrastructural units related to acupoint functions exist, thereby providing a morphological foundation for elucidating the initial cellular responses to acupuncture.

The study subjects included commonly used acupoints in rats, mice, rabbits, and sheep. Focusing on the ultrastructure of acupoint regions, this study primarily employed electron microscopy techniques. It examined the spatial relationships and interactions between TCs and their Tp in acupoint regions and various components, including nerves, blood vessels, lymphatic vessels, immune cells, mast cells, extracellular vesicles (including exosomes), skin derivatives, acupoint matrix, and its fibers.

TEM revealed that TC and its Tp in the acupoint frequently entangled with or accompany various components, such as nerves, blood vessels, lymphatic vessels, immune cells, mast cells, extracellular vesicles (including exosomes), skin derivatives, acupoint matrix, and fibers. Some Tp even extended into the interior of structures, directly contacting or connecting with target components to form new structural units-“Telocyte-entanglement complexes” (TCEC). Notably, TC and its Tps could simultaneously entangle with one or multiple special components, thereby forming distinct morphological units among the TCECs. The extensive connectivity characteristic of TC indicated the ultrafine evidence of the "holistic view" concept in TCM. Furthermore, TC wrapped around fibers and forms developed adhesive spots, anchoring tightly to the matrix within acupoints, which might be conducive to explaining that TC was the initial cell of acupuncture effects. This observation provided the morphological evidence for the connective and integrative functions of TC within acupoint tissues and has been preliminarily validated by acupuncture.

The study systematically revealed the complex spatial relationships between TC and Tp within acupoint regions and various structural components, identifying a neglected ultrastructural unit - TCEC at acupoints. This structure reflected both the integration of local cells and tissues and provided a morphological foundation for understanding the initial cellular-mechanical responses to acupuncture. The findings not only clarified the biological basis of acupoints but also provided a new research perspective at the ultrastructural level for elucidating the mechanisms underlying acupuncture effects.