“长强”穴药线植入对肛门切口痛大鼠机械痛阈及脊髓磷酸化p 38丝裂原活化蛋白激酶的影响

Effect of Medicated-catgut Embedding at“Changqiang”(GV 1)on Mechanical Pain Threshold and P 38 MAPK Expression in Spinal Cord Tissue in Anus Incisional Pain Rats

目的:探讨"长强"穴药线植入对肛门部切口痛模型大鼠止痛的作用机制。方法:SD大鼠随机分为空白组、模型组、长强穴药线植入组、非经非穴药线植入组,每组10只。建立肛门部切口痛模型,长强穴药线植入组用药线植入"长强"穴,非经非穴药线植入组用药线植入胁下非经非穴点。各组于术前及术后4、8、12、24h用Von Frey纤维丝测定大鼠术区及肛门左侧距术区15 mm处伤害性机械刺激的回缩阈值(MWT)。采用免疫组化SP法检测脊髓磷酸化p 38丝裂原活化蛋白激酶(p-p 38MAPK)水平。结果:与空白组比较,模型组术区及距术区15mm处MWT在术后4、8、12、24h均明显降低(P<0.05),脊髓p-p 38MAPK水平明显升高(P<0.05)。与模型组比较,长强穴药线植入组术区MWT在术后8、12、24h明显升高(P<0.05),距术区15mm处MWT在术后12、24h明显升高(P<0.05),术后24h脊髓p-p 38 MAPK水平明显降低(P<0.05)。非经非穴药线植入组术区及距术区15 mm处MWT、术后24h脊髓p-p 38MAPK水平与模型组比较,差异均无统计学意义(P>0.05)。结论:"长强"穴药线植入能显著提高肛门部切口痛模型大鼠的机械痛阈,其机制可能与"长强"药线植入降低切口痛大鼠脊髓p-p 38 MAPK水平有关,非经非穴药线植入不具有相同作用。

Objective To observe the effect of medicated-catgut embedding at ＂Changqiang＂（GV 1） on regional pain reaction and expression of p 38 MAPK in the dorsal horn of spinal cord in anus incisional pain rats, so as to explore its analgesic mechanism. Methods Forty male SD rats were randomly divided into control, model, GV 1-embedding and sham acupoint embedding groups （n = 10 rats in each group）. The anus incisional pain model was established by making a radial incision （about 10 mm length） at the left lithotomy position of the anus with a surgical knife, and the mechanical pain threshold （PT） was measured by using a Von Frey before and 4, 8, 12, 24 h after operation. The medicated-catgut （about 12.5 mm length/kg body weight） was implanted in the subcutaneous tissue of GV 1 region. The immunoactivity of p 38 MAPK was determined by immunohistochemistry. Results Compared with the control group, the mechanical PTs were significantly decreased 4, 8, 12 and 24 h after operation both at the site of incision and about 15 mm proximal to the site of incision in the model group （P〈0.05）, and the immunoactivity of phosphorylated （p）-p 38 MAPK in the superficial layer of dorsal horns of lumbar spinal cord was significantly increased（24 h）after operation（P〈0.05）. Compared with the model group, the PTs were significantly increased 8, 12 and 24 h after operation at the site of incision, and 12 h and 24 h at the site about 15 mm proximal to the incision region （P〈0.05）, and the immunoactivity level of p-p 38 MAPK was significantly down-regulated in the GV 1-embedding group （P〈0.05）. No significant changes were found in the PT and p-p 38 MAPK immunoactivity levels in the sham acupoint embedding group （P〉0.05）.Conclusion Medicated-catgut embedding at ＂Changqiang＂（GV 1） has an analgesic effect in anus incisional pain model rats, which may be related to its effect in down-regulating the expression of p 38 MAPK in the dorsal horn of lumbar spinal cord.