Objective: To observe the effect of perpendicular and subcutaneous transverse needling at "Sanyinjiao" (SP6) on visceral pain behavior, arginine vasopressin (AVP) content in the serum, uterine tissues, spinal cord and hypothalamus and expression of AVP receptors AVPR1A and AVPR1B in the uterine tissues, spinal cord and hypothalamus in cold-stasis (stasis due to pathogenic cold) type dysmenorrhea rats, so as to explore their mechanisms underlying pain relief.
Methods: Forty female SD rats were randomly divided into blank control, model, perpendicular needling and transverse needling groups, with 10 rats in each group. The cold-stasis dysmenorrhea rat model was established by exposure in a freezer (-25 ℃) for 4 h, once daily for 5 days, and subcutaneous injection of estradiol benzoate (once daily for 10 days) and intra-abdominal injection of oxytocin injection (once). For rats of the two acupuncture groups, acupuncture needles were inserted into the bilateral SP6 perpendicularly or transversely to a depth of about 4-5 mm, and retained for 20 min. The abdominal pain behavior was assessed by recording the writhing latency and scaling the rats' writhing reactions after modeling. The contents of AVP in the serum, uterus, spinal cord and hypothalamus tissues were assayed using ELISA and the expression of AVPR1A and AVPR1B in the uterus, spinal cord and hypothalamus was measured by using Western blot and quantitative real time-PCR, respectively.
Results: After mode-ling and compared with the blank control group, the writhing latency was significantly shortened (P<0.05), and the writhing score in the first 20 min was significantly increased (P<0.01) in the model group. After the intervention, the writhing latency was significantly prolonged (P<0.01), and the writhing scores in 20 min were significantly decreased (P<0.01) in the two needling groups. The AVP contents were obviously increased in the serum and uterine tissue (P<0.05, P<0.01) but decreased appa-rently in the spinal cord and hypothalamus tissues (P<0.01, P<0.05), and the expression levels of AVPR1A or AVPR1B protein and mRNA were markedly increased in the uterine tissues (P<0.01, P<0.05), and significantly decreased in the spinal cord and hypotha-lamus in the model group relevant to the control group (P<0.05, P<0.01). Following the intervention, The AVP content in the serum of the perpendicular needling group (P<0.05) and that in the uterus of the two needling groups were significantly decreased (P<0.01), as well as that in the hypothalamus was obviously increased in the two needling groups (P<0.05). The expression levels of AVPR1A protein and mRNA in the uterus were significantly down-regulated in the two needling groups (P<0.01, P<0.05) and AVPR1B protein in the hypothalamus of the perpendicular needling group was up-regulated (P<0.05). Moreover, no significant differences were found between the two needling groups in regulating the related indexes mentioned above (P>0.05).
Conclusion: Both perpendicular and subcutaneous transverse needling at SP6 have an immediate analgesic effect in cold-stasis type dysmenorrhea rats, which may be related to their effects in regulating AVP levels and its receptor expression in the uterine and hypothalamus.
目的：观察直刺、沿皮刺“三阴交”穴对寒凝证类痛经大鼠血清、子宫、脊髓及下丘脑中精氨酸加压素(AVP)及其受体(AVPR1A、AVPR1B)的影响，探讨不同刺法即刻镇痛效应的机制。方法：雌性SD大鼠随机分为空白组、模型组、直刺组、沿皮刺组，每组10只。采用全身冷冻加雌二醇注射法制备寒凝证类痛经模型。直刺组、沿皮刺组分别直刺或沿皮刺“三阴交”穴，留针20 min。记录各组大鼠的扭体反应情况。采用ELISA法、Western blot法、荧光定量PCR法分别检测大鼠血清、子宫、脊髓以及下丘脑的AVP含量、AVPR1A与AVPR1B蛋白及mRNA表达。结果：与空白组比较，模型组扭体潜伏期缩短(P<0.05)，20 min内扭体评分显著升高(P<0.01)；与模型组比较，直刺及沿皮刺组扭体潜伏期均明显延长(P<0.01)，20 min内扭体评分显著降低(P<0.01)。与空白组比较，模型组血清和子宫AVP含量升高(P<0.05，P<0.01)、脊髓和下丘脑AVP含量降低(P<0.01，P<0.05)，子宫AVPR1A蛋白及mRNA表达升高(P<0.01，P<0.05)、脊髓AVPR1A蛋白及mRNA降低(P<0.05，P<0.01)，下丘脑AVPR1B蛋白及mRNA表达降低(P<0.01)。与模型组比较，直刺组血清AVP含量降低(P<0.05)，下丘脑AVPR1B蛋白表达升高(P<0.05)；直刺与沿皮刺组子宫AVP含量均显著降低(P<0.01)，下丘脑AVP含量均升高(P<0.05)，子宫AVPR1A蛋白及其mRNA表达均降低(P<0.01，P<0.05)。直刺组与沿皮刺组各指标间差异无统计学意义(P>0.05)。结论：直刺、沿皮刺“三阴交”穴对类痛经大鼠均显示出即刻镇痛效应，其机制可能与针刺对子宫及下丘脑AVP及其受体的调节有关。.
Keywords: Arginine vasopressin; Arginine vasopressin receptors; Dysmenorrhea; Perpendicular needling; Transverse needling.