不同频度电针治疗大鼠慢性神经源性痛的疗效比较

Comparison of the Therapeutic Effects of Electroacupuncture with Different Interval for Treatment of Chronic Neuropathic Pain in Rats

目的 :比较不同频度电针治疗大鼠慢性神经源性痛的疗效。方法 :大鼠L5/L6 脊神经结扎慢性神经源性痛模型 (ChungModel) ,给予不同频度的电针治疗 (每天 1次、2天 1次、3天 1次和 4天 1次 ) ,观察疗效。采用引起缩足的机械刺激阈值 ( 50 % )来评价机械性痛觉超敏 ,用大鼠5min内在 5± 1℃冷板上的抬脚次数来反映冷诱发的持续性疼痛。结果 :随着电针次数的增加 ,3天 1次组、4天 1次组、2天 1次组的镇痛效果均可以得到累加。而在四组不同频度中 ,3天 1次组后续镇痛作用效果最好 ,对机械性痛超敏的抑制至电针后 48hr,对冷诱发的持续性疼痛的抑制持续至电针后 1周。经统计学检验 ,3天 1次组与其他针刺频度组镇痛作用的差异有统计学意义 (P<0 .0 1 ,P <0 .0 0 1 )。结论 :电针频度是影响疗效的重要因素 ,综合累加效应和后续效应 ,3天

Objective: Chronic neuropathic pain syndrome characterized by its long duration, slow recovery and difficulty to control in clinic practice makes it more serious physically and psychologically. The present study aims at investigating the optimal interval parameter of electroacupuncture (EA) therapy. Methods:In 10% chloral hydrate (300 mL/kg) anesthetized female SD rats, L 5/L 6 nerve ligation induced chronic neuropathic pain model (Chung model) was used to assess the effect of EA on neuropathic pain. Mechanical allodynia was assessed by using 50% paw withdrawal threshold and cold-induced ongoing pain was detected by the number of paw lift within 5 minutes when free rat was put on to the 5±1 ℃cold plate. 120 rats were divided into 5 groups: control group and 4 intervals of EA subgroups (one-day, 2-day, 3-day and 4-day subgroups, i.e., treatment was given once everyday, every 2, 3 and 4 days separately, 6 sessions altogether). Bilateral 'Jiaji' (EX-B 2, L 5, at the sacro-iliac articulation level, about 0.5 cm to the spinal column) and 'Weizhong' (BL 40) were punctured and stimulated electrically (2 Hz, wave width 0.6 ms, 0.5～2 mA and duration 30 min) following performing uniform reinforcing-reducing needling manipulation. Results: 7 days after nerve ligation, 50% paw withdrawal threshold lowered significantly and the number of paw lift within 5 minutes increased pronouncedly on the affected side (P<0.001) in comparison with those of healthy side. Among the 4 intervals, 2-day, 3-day and 4-day subgroups rather than 1-day subgroup had an obvious accumulative analgesic effect. As for the long-lasting analgesic effect, 3-day subgroup was the best. Longer lasting analgesic effect was following this interval choice (48 hours for mechanical allodynia and 10 days for cold-induced ongoing pain). As for the accumulative effect and long-lasting analgesic effect (24 hours for mechanical allodynia and 1 week for cold-induced ongoing pain), 3-day group had done a better effect than the others (P<0.01 or 0.001). Conclusion: Optimal interval is a critical factor for the analgesic effect of EA. The results of the present study indicate that one session of EA treatment every 3 days is the optimal interval.