不同电流强度电针缓解大鼠胫骨癌痛的量效关系及抑制脊髓GFAP的表达

目的:观察不同电流强度电针与不同剂量吗啡结合缓解大鼠胫骨癌痛的量效关系,探讨其可能的作用机制,为电针与吗啡结合缓解癌症疼痛适宜参数的选择提供实验依据.方法:将雌性Wistar大鼠100只随机分为正常对照组(10只)、模型组(10只)及治疗组(80只),治疗组按不同电流强度与吗啡剂量结合的2因素3水平组合又分为8组,每组10只.大鼠右侧胫骨上段骨癌造模后第15天起,治疗组以2 Hz/100 Hz疏密波电针“夹脊”穴,给各组大鼠以不同的刺激参数治疗,每天1次,连续6d.检测大鼠治疗前和首次治疗后0 min、1h、2h和5h时及治疗3次后、治疗6次后痛阈.采用免疫组织化学方法测定脊髓背角胶质原纤维酸性蛋白(GFAP)表达.结果:首次治疗后0 min、1h和2h时,2 mA电针与1mA电针均有提高痛阈的作用(均P＜0.01),但两者间比较差异无统计学意义(均P＞0.05);首次治疗后5h时,2 mA电针仍有提高痛阈的作用(均P＜0.01),1mA电针提高痛阈作用不显著(P＞0.05);治疗3次和6次后,2 mA电钎和1mA电针均有提高痛阈的作用(均P＜0.01),且2 mA电针的作用优于1mA电针(P＜0.05),并与5 mg/(kg·d)吗啡有协同作用(P＜0.05).治疗6次后,2 mA和1mA电针均有抑制脊髓背角GFAP表达的作用(均P＜0.01),两者比较差异无统计学意义(P＞0.05);5 mg/(kg· d)和2.5 mg/(kg·d)吗啡均无抑制作用(P＞0.05).结论:不同电流强度电针缓解大鼠胫骨癌痛的作用存在量效关系,2 mA电针的作用优于1mA电针,并与5 mg/(kg·d)吗啡有协同作用.电针可能通过抑制脊髓背角GFAP表达来实现协同吗啡缓解大鼠胫骨癌痛的作用.

Study on dose-effect relationship of electroacupuncture with different current intensities alleviating tibial cancer pain and inhibition of expression of spinal GFAP in rats

Objective To observe the dose-effect relationship of electroacupuncture of different current intensities combined with Morphine of different dosage on alleviating the rats’ tibial cancer pain,and explore the possible mechanism,which could provide the experiment basis for alleviating the tibial cancer pain by electroacupuncture combined with Morphine.Methods One hundred female Wistar rats were randomly divided into a normal group,a model group and eight treatment groups,10 cases in each group.The rats in the treatment groups were treated by combined therapies of electroacupuncture of different intensities with 2 Hz /100 Hz dense-disperse wave on "Jiaji"(EX-B 2)and different dosage Morphine in 2 factor 3 level conditions,once a day for 6 days.The pain thresholds were observed before the treatment and 0 min,1 h,2 h and 5 h after the first treatment as well as after 3 and 6 times of treatments.The glial fibrillary acidic protein(GFAP) expression was determined by immunohistochemical method.Results The rats’ pain thresholds were significantly increased with electroacupuncture of 2 mA and 1 mA(all P<0.01) on the 0 min,1 h and 2 h of the first treatment,between which there were no significant differences(all P>0.05).The pain threshold was still increased by electroacupuncture of 2 mA on the 5 h of the treatment(P<0.01),while that of 1 mA failed to take effect(P>0.05).After 3 and 6 time s of treatments,both electroacupuncture of 2 mA and 1 mA had the effect of increasing the pain threshold(all P<0.01),and the effect of 2 mA was superior to that of 1 mA(P<0.05),had the synergistic effect with 5 mg/(kg·d) Morphine(P<0.05).After 6 times of treatments,both electroacupuncture of 2 mA and 1 mA could inhibit the expression of GFAP(both P<0.01),and there was no significant difference between them(P>0.05).Both of 5 mg/(kg·d) and 2.5 mg/(kg·d) of Morphine,however,didn’t bring about inhibition effect(P>0.05).Conclusion There is a does-effect relationship on electroacupuncture of different current intensity for alleviating the tibial cancer pain in rats.The electroacupuncture with 2 mA,which is better than that with 1 mA,has the synergistic effect with 5 mg/(kg·d) of Morphine.The electroacupuncture can inhibit the expression of GFAP to cooperate with Morphine for the purpose of alleviating the rats’ tibial cancer pain.