Comparison of Extracellular and Intracellular Fluid Distribution Between Stomach Meridian or Gallbladder Meridian and Their Neighboring Tissues of Lower Leg in Healthy Volunteers

Abstract

To compare differences of extracellular fluid impedance (Re) and intracellular fluid impedance (Ri) between the Stomach(ST) Meridian or Gallbladder(GB) Meridian and their neighboring non-meridian sites of the left lower leg at the same level, so as to explore the distribution characteristics of body fluid in the meridian. Sixteen healthy volunteers were enrolled in the present study. The Re and Ri were detected by using Ag/AgCl electrodes and a digital lock-in amplifier. The measuring electrodes (at an interval of about 3 cm) were separately fixed to the skin sites covering the running courses of the ST Meridian (in the lateral interspace of the anterior tibial muscle)and the GB Meridian (in the interspace of the anterior edge of the fibula), and the excitation electrodes (at an interval of about 9 cm) respectively fixed to the skin sites covering the anterior tibial muscle and the interspace between the anterior tibial muscle and the tibia (about 2 cm and 5 cm lateral to the ST and GB meridians, and about 3－4 cm and 6－8 cm lateral to the ST and GB meridians, respectively). A 100 µA constant current with frequencies from 1 kHz to 100 kHz delivered via an excitation electrode was applied to the site (control spots of the ST Meridian), and signals of the voltage amplitude and phase difference of the tissues fed to the lock-in amplifier via the measuring electrode were collected, followed by measuring those of the GB Meridian and control sites. The circumference of the lower leg around the two excitation and measuring electrodes was measured. Then the cole-cole curve fitting was performed to calculate the Ri and Re, as well as the intracellular fluid resistivity (ρi) and extracellular fluid resistivity (ρe) of the ST and GB meridians, the related muscles and interspace lateral to ST or GB (ST/GB) meridians at the same level. The Ri and Re (Ω) values of the ST, GB, the muscle lateral to ST/GB and the interspace lateral to ST/GB were 19.1±1.3 and 28.3±1.4, 15.8±1.9 and 25.7±2.0, 19.6±1.3 and 31.3±1.6, and 19.4±1.2 and 32.4±1.6, respectively. The Re values were significantly lower at the ST and GB meridians than at the muscle lateral to and the interspace lateral to both meridians (P<0.05). The ρi and ρe values (Ω•cm) of the ST, GB, the muscle lateral to and the interspace lateral to ST/GB were 658.9±78.5 and 953.8±75.3, 528.0±90.1 and 833.9±101.7, 669.9±71.8 and 1 059.8±86.0, 655.9±64.8 and 1 099.3±93.3, respectively. The ρi and ρe values were significantly lower at the GB Meridian Than at the other three locntions, and the ρe value of ST Meridian was significantly lower than those of the muscle lateral to and the interspace lateral to ST/GB meridians (P<0.01)．. The Ri, Re, ρi and ρe values of the ST and GB meridians are significantly lower than those of their neighboring tissues at the same levels of the lower leg, suggesting a more extracellular fluid in the meridian running course and providing evidence for our speculation that the meridian is a hydraulic resistance channel.