A COMPARATIVE STUDY ON HYPOTHALAMIC MECHANISMS OF ANALGESIA INDUCED BY FOUR KINDS OF ACUPUNCTURE THERAPIES IN ADJUVANT ARTHRITIS RATS

Objective: To compare the mechanisms of analgesia induced by four kinds of acupuncture therapies at the hypothalamic level in adjuvant arthritic rats. Methods: Forty-eight SD rats were randomized into normal, model, electroacupuncture (EA), filiform needle (FN), pricking blood-letting (BL) and point injection (PI) groups, with 8 cases in each. EA (20-100 Hz, 2-4 V and duration of 20 min), FN, BL PI were respectively applied to “Kunlun” (昆仑BL 60). Arthritis model was established by injecting complete Freund’s adjuvant (0.1 mL) into the rat’s right foot pad. Behavioral reactions, pain threshold (latency of tail flick to heat stimulation) and local swelling severity (foot volume) were detected; the contents of β-endorphin (β-EP) and adrenocorticotropin (ACTH) were assayed with radioimmunoassay; and the expression of pro-opi-omelanocortin (POMC) mRNA in hypothalamus were determined with hybridization method. Results: The pain threshold was significantly enhanced by all the four kinds of acupuncture therapies, and the effects of EA and PI were more obvious (P<0.05, P<0.01). The severity of local swelling was markedly alleviated by all the four kinds of acupuncture therapies (P<0.01) without significant differences among them (P>0.05). The content of β-EP in the hypothalamus was obviously elevated by EA and FN (P<0.05, P<0.01), and the effect of EA was more obvious, but no marked effect of BL or PI on β-EP was found (P>0.05). The content of ACTH in hypothalamus was considerably elevated by PI (P<0.05), but not by the other three therapies. The expression of POMCmRNA in hypothalamus was significantly strengthened by EA and FN (P<0.01), but not by the other two therapies. Conclusion: EA, filiform needle, blood-letting and point-injection all can produce analgesic effect in adjuvant arthritis rats, the effect of EA and filiform needle may be related to their resultant increase of hypothalamic β-EP, and that of point-injection related to the increase of hypothalamic ACTH level.

Objective.. To compare the mechanisms of analgesia induced by four kinds of acupunture therapies at the trypothalamic level in adjuvant arthritic rats. Methods： Forty-eight SD rats were randomized into normal, model, electroacupuncture （EA）, filiform needle （FN）, pricking blood-letting （BL） and point injection （PI） groups, with 8 cases in each. EA （20-100 Hz, 2-4 V and duration of 20 min）, FN, BL PI were respectively applied to “Kunlun” （昆仑 BL 60）. Arthritis model was established by injecting complete Freund＇s adjuvant （0.1 mL） into the rat＇s right foot pad. Behavioral reactions, pain threshold （latancy of tail flick to heat stimulation） and local swelling severity （foot volurne） were detected; the cordents of β-endorphin （β-EP） and α- drenocortiootropin （ACTH） were assayed with radioimmunoassay; and the expression of pro-opi-omelanocortin （POMC） mRNA in hypot were determined with hybridization method. Results： The pain threshold was significantly enhanced by all the four kinds of acupuncture therapies, and the effects of EA and PI were more obvious （P〈0.05, P〈0.01）. The severity of local swelling was markedly alleviated by all the four kinds of acupuncture therapies （ P〈 0.01 ） without significant differences among them （P 〉 0.05）. The content of β-EP in the hypothalamus was obviously elevated by EA and FN （P〈 0.05, P 〈 0.01 ）, and the effect of EA was more obvious, but no marked effect of BL or PI on β-EP was found （ P 〉0.05）. The content of ACTH in hypothalamus was considerably elevated by PI （P〈0.05）, but not by the other three therapies. The expression of PCMCmRNA in hypothalamus was significantly strengthened by EA and FN （P〈0. 01）, but not by the other two therapies. Conclusion：EA, flliform needle, blood-letting and point-injection all can produce analgesic effect in adjuvant arthritis rats, the effect of EA and filiform needie may be related to their resultant increase of hypothalamic β-EP, and that of point-injectiON related to the increase of hypothalamic ACTH level.