Visualized regional hypodermic migration channels of interstitial fluid in human beings: are these ancient meridians?

Background: Since the 1980s, many studies have indicated there are hypodermic migration channels of radiotracer along meridians independent of lymphatic and blood vessels in vivo. However, the radioactive trajectories were not clear enough to identify the anatomic structures in the living body.

Objectives: To establish an alternative method to image the specific fluid pathways, we hypothesized that a minimal amount of low molecular weight tracer could enter the specific channels and by magnetic resonance imaging technique, we could image the regional channels originating from the acupoints on 6 yin meridians of forearm and lower leg.

Design And Results: Seven (7) healthy volunteers were injected hypodermically with a minimal amount of tracer into 6 acupoints on 6 yin meridians of the hand and foot. We found a total of 6 regional specific channels in one forearm and one lower leg of each subject, respectively, but no specific channels were visualized following injection of the tracer into the sites of nonacupoints. Magnetic resonance angiography confirmed the specific channels were not the superficial veins in the subcutis. Subsequent acupuncture needling studies revealed that migration of tracer along each of the specific channels could not be interrupted by acupuncture needling and remained intact, which was different from the nature of either lymphatics or blood vessels.

Conclusions: We imaged 6 regional migration channels originating from 6 acupoints on 6 yin meridians of hand and foot by injecting a minimal amount of tracer into acupoints directly in humans. The responses of the subcutaneous specific channels to acupuncture needling are different from those of lymphatic or blood vessels and coincide partially with the characteristics of acupuncture therapeutics, suggesting the existence of meridian-like channels in humans. These findings may contribute to further research on the specific interstitial fluid drainage.