热补针法镇痛后效应及其对关节局部组织β-内啡肽和前列腺素E_2的影响

Observation on the Analgesic Effect of Heat-reinforcing Needling Manipulation for Acute Arthritis and the Concomitant Changes of β-EP and PGE_2 Contents in the Local Joint Tissue in Rabbits

目的:观察热补针法的镇痛后效应,探讨其镇痛的外周机制。方法:60只青紫蓝兔随机分为正常组、模型组、捻转组和热补组,后2组又随机分为针后即时、针后0.5 h、针后1 h和针后2 h亚组,每组各6只。用卵蛋白诱导造成关节炎疼痛模型。针刺双侧"合谷"和"足三里"1次,留针30 min,捻转组用捻转针法,热补组用热补针法。以K+导入法引起家兔腿收缩的最小电流强度作为痛阈;取关节局部组织,用放射免疫法测定β-内啡肽(EP)及前列腺素(PG)E2含量。结果:模型组痛阈显著低于正常组(P<0.01);与模型组比较,捻转组和热补组针后各时刻痛阈均显著升高(P<0.01,P<0.05);热补组即时痛阈与捻转组比较差异无统计学意义(P>0.05),其余时刻痛阈热补组均高于捻转组(P<0.05,P<0.01)。模型组关节局部组织中β-EP、PGE2含量均高于正常组(P<0.05,P<0.01);与模型组比较,捻转组和热补组各时刻β-EP含量均显著升高(P<0.01,P<0.05),而PGE2含量均显著降低(P<0.01,P<0.05);与捻转组相比,热补组针后2 hβ-EP含量显著增高(P<0.05),而热补组针后即时PGE2含量显著降低(P<0.01)。结论:热补针法镇痛后效应优于捻转针法;关节局部β-EP和PGE2含量变化与两种针法镇痛后效应不同无明显相关趋势。

Objective To observe the analgesic effect of heat-reinforcing needling manipulation for acute inflammatory arthritis and its underlying mechanism in experimental rheumatoid arthritis rabbits. Methods A total of 60 rabbits were randomized into control （n = 6）, model （ n = 6）, needle-twirling （ n = 24） and heat-reinforcing （ n = 24） groups, and the later 2 groups were further divided into 0 h, 0.5 h, 1 h and 2 h subgroups,with 6 cases in each. Rheumatoid arthritis model was established by injecting mixed solution of egg-albumin （4 mg/ml） and equal volume of complete Freund＇s adjuvant （CFA） into the subcutaneous tissue （6 points around the shoulder,0.2 ml/point）. Fourteen days later,the injection was repeated once again,and another 6 days later,egg-albumin （0.4 ml, 20 mg/ml） solution was injected into the bilateral knee-joints. ＂Zusanli＂ （ST 36） and ＂Hegu＂ （LI 4） were punctured and stimulated by needle-twirling or by heat-reinforcing needling technique for 1 rain, with the needle retained for 30 min. The pain threshold of the paw was detected with K^＋ import stimulation method. β-EP and PGE2 contents of the joint tissue were assayed with radioimmunoassay. Results Compared with model group, the pain threshold of needle-twirling group and heat-reinforcing group at each time-point increased significantly （P〈0.01, P〈0.05）. Compared with needle-twirling group,the pain threshold of heat-reinforcing group at 0.5 h, 1 h and 2 h subgroups increased significantly （P〈0.05, P〈0.01）. Both β-EP and PGE2 contents of model group were significantly higher than those of control group （P〈0.01, P〈0.05）. In comparison with model group, β-EP contents of needle-twirling group and heat-reinforcing group at each time-point increased significantly （ P〈0.01, P〈0.05）, and PGE2 contents of needle-twirling group and heat-reinforcing group at each time-point decreased significantly （P〈0.01, P〈0.05）. The β-EP content of heat-reinforcing group was significantly higher than that of needle-twirling group at 2 h （P〈0.05）, while PGE2 content of the former group was significantly lower than that of needle-twirling group at 0 h （ P〈0.01 ）. Conclusion Both needle-twirling and heat-reinforcing needling can effectively raise the pain threshold in acute arthritis rabbits, which my be closely associated with their effects in upregulating β-EP content and lowering PGE2 level in the local joint tissue. The analgesic effect of heat-reinforcing needling manipulation is superior to that of needle-twirling.