Effect of Zusanli (ST.36) Electroacupuncture at Two Frequencies on the Bioavailability of 99mTc-Sodium Pertechnetate and on Labeling of Blood Constituents in Rats

Objectives: A study was performed on the effects of stimulation at Zusanlipoint (ST.36) by electroacupuncture (EA) at two frequencies on the bioavailability of 99mTc-sodium pertechnetate (Na99mTcO4) in rats. Methods: Forty Wistar rats were divided into four groups: untreated control, treated by manual acupuncture at ST.36 bilaterally, treated by EA at 2 Hz at ST.36 bilaterally, and the same site at 100 Hz bilaterally. Na99mTcO4 (7.4 MBq) was administrated via the ocular-plexus and, 20 minutes before sacrifice, blood was withdrawn for radiolabeling assay (BRL). In the bioavailability analysis, organs and tissues were isolated, their radioactivity determined, and the percentage of injected dose per gram of organ or tissue (%ID/g) and the %ID were calculated for each organ or tissue (%ID/ot). For BRL, the plasma and blood cells isolated, and the fractions also precipitated with 5% trichloroacetic acid to separate the soluble and insoluble fractions; these were assessed as percentage of injected dose (%ID) in blood (%ID/b). Results: The results showed significant differences in the %ID/g in some organs and tissues in comparison with controls; lung (p= 0.0013), spleen (p= 0.0085), pancreas (p= 0.0167), liver (p= 0.0003), stomach (p< 0.0001), small-intestine (p= 0.0181), large-intestine (p= 0.04099), urinary-bladder (p= 0.0271), thyroid (p< 0.0001), muscle (p= 0.0187); %ID/ot in spleen (p= 0.0349); and %ID/b in blood sample (p= 0.0235). In the blood labeling analyses, EA in either frequency significantly increased insoluble fraction/blood cells (p< 0.0001).