Based on the distribution characteristics of mast cells and existing mechanistic evidence

the study explores the potential biological effects of shallow needling control (sham-acupuncture). Regarding cellular distribution

mast cells exhibit a physiological characteristic of dense distribution in both the dermis and subcutaneous tissue

predominantly in the distal regions

and show a higher density in acupoint areas compared with non-acupoint areas. At the puncture site

shallow needling primarily targets the dermis and the superficial subcutaneous tissue

with these two layers overlapping anatomically. Regarding its mechanism of action

acupuncture can induce local mast cell degranulation through mechanical stimulation

thereby releasing bioactive substances that subsequently activate relevant signaling pathways to produce analgesic effect. The study proposes that the shallow needling control at the same acupoint or non-acupoint not merely obtains placebo effect

but also involves potential biological mechanism associated with mast cells

aiming to provide new insights for future clinical trial design and research on the underlying mechanism of acupuncture and sham-acupuncture.