[Observation on Acupoint Sensitization Phenomenon in Experimental Myocardial Ischemia Rabbits]

To develop an animal model suitable for the study of acupoint sensitization in myocardial ischemia(MI) animals by observing changes of the mechanical withdrawal threshold (pain threshold, PT).

Twenty New Zea-land rabbits were randomly divided into control and model groups (n=10 in each group). The controllable MI model was set up by installing a balloon occluder at the left anterior descending branch of the left coronary artery. Air inflation of the balloon was given for 5 min/time, twice a day (4-hours' interval) for continuous 5 days (the first stage of MI), with one day's rest, then, another 5 days' air inflation was conducted again (2^nd stage of MI). Electrocardiogram (ECG) of the standard limb lead Ⅱ was recorded for assessing MI, and myocardial 2,3,5-triphenyltetrazolium chloride (TTC) staining was used to verify the degree of ischemic myocardium. The PT of the skin areas of "Neiguan" (PC 6), "Shenmen" (HT 7),"Taixi"(KI 3),hind paw(HP)was detected under conscious conditions,before MI, on day 8(after recovery from MI), day 14 (the first stage of MI), and day 20 (the second stage of MI), respectively.

The controllable MI model was successful due to a marked elevation of ECG ST Ⅱ after inflation of the implanted balloon and a distinct recovery after balloon deflation (P<0.05). The myocardial TTC staining showed that the area of the myocardial necrosis was about 10%. The PT values were significantly decreased in PC 6 area at the first stage of MI and in both PC 6 and HT 7 regions at the 2^nd stage of MI (P<0.01), suggesting a close relationship between the acupoints of the Pericardium and Heart meridians and the heart in terms of the basic theory of Chinese medicine.

MI may induce a reduction of PT of some related acupoints in MI rabbits, and the controllable MI model of the present study is helpful to the study of acupoint sensitization phenomenon after occurrence of visceral diseases.