Acupuncture produced a localized, lasting reduction in tissue water at specific body points, detectable only with the smallest measurement probe.
Healthy volunteers were randomly assigned to acupuncture or control conditions, with assessors blinded to group allocation. Researchers measured tissue dielectric constant, an indicator of local water content, at the stomach 36 and spleen 6 acupuncture points before treatment and at two intervals after needle removal. Measurements used probes of three different diameters to assess effects at different tissue depths or spatial scales, while electrical impedance was measured as an independent validation method.
The smallest probe detected reduced tissue water content at both acupuncture points after needling, and this reduction persisted through the later assessment. Larger probes did not identify comparable changes, suggesting that acupuncture effects were confined to a highly localized superficial tissue environment. Electrical impedance findings supported these changes by indicating greater electrical current passage at the treated points, reinforcing tissue dielectric measurement as a means of detecting local physiological responses to acupuncture.
