Department of Pain Medicine, Hangzhou Red Cross Hospital, Hangzhou, 310003, China.
Department of Cardiology, The Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, 310009, China.
Chin J Integr Med. 2019 Jun;25(6):462-467. doi: 10.1007/s11655-018-3057-4. Epub 2018 Nov 22.
To study the effects of electroacupuncture (EA) in chronic constrictive injury (CCI) rat model and the expression of N-methyl-D-aspartate receptor type 2B (NR2B) in ipsilateral spinal dorsal horn in rats to explore the analgesic mechanisms of EA.
According to the random number table, totally 180 rats were evenly divided into a sham group, a CCI group, and an EA group. CCI model was conducted with four 4-0 chromic gut ligatures loosely ligated around the left sciatic nerve 1 cm above the trifurcation. Rats in the EA group received 2 Hz EA therapy bilaterally at acupoints of Zusanli (ST 36) and Sanyinjiao (SP 6) once daily (30 min/d) for 30 days after surgery. Paw withdrawal thresholds (PWTs) were measured on 0 (baseline), 1, 3, 7, 15, 30 days after surgery. Rats were sacrificed on 0, 1, 3, 7, 15 and 30 days after surgery, and the L4-5 segments of spinal cord were removed to detect the expression of NR2B by immunohistochemistry and quantitative polymerase chain reaction.
PWTs in the CCI group were significantly lower than the sham group at Day 1-30 after surgery, and reached its lowest at Day 1 (P<0.01). After EA treatment, the PWTs recovered rapidly and were significantly higher than those in the CCI group on 3, 7, 15 and 30 days after surgery (P<0.01). The numbers of NR2B-immunoreactive cells of the CCI group significantly increased after CCI surgery compared with the sham group (P<0.01). Compared with the CCI group, stimulation of EA markedly decreased the numbers of NR2B-immunoreactive cells at Day 3, 7, 15 and 30 (P<0.05). In the sham group, NR2B mRNA was expressed at a low level. It increased after CCI surgery, which increased rapidly at Day 7 (P<0.01) and reached its peak value at Day 15 (P<0.01). After EA stimulation, relative quantity of NR2B mRNA expression was less than that in the CCI group at Day 15 and 30 (P<0.05).
Low frequency of EA had antinociceptive effect in CCI rat model. The analgesic effects of EA might be through the inhibition of NR2B.
研究电针对慢性缩窄性损伤（CCI）大鼠模型的影响，以及大鼠同侧脊髓背角中 N-甲基-D-天冬氨酸受体 2B（NR2B）的表达，探讨电针的镇痛机制。
根据随机数字表，将 180 只大鼠平均分为假手术组、CCI 组和电针组。CCI 模型通过在坐骨神经分叉上方 1cm 处用 4 根 4-0 铬肠线将左坐骨神经松散地结扎 4 次来建立。手术后，电针组大鼠每天接受双侧足三里（ST36）和三阴交（SP6）的 2Hz 电针治疗，每次 30 分钟，共 30 天。在手术前（基线）、手术后 1、3、7、15、30 天测量大鼠的足底退缩阈值（PWT）。手术后 0、1、3、7、15 和 30 天处死大鼠，取出 L4-5 段脊髓，通过免疫组织化学和定量聚合酶链反应检测 NR2B 的表达。
CCI 组大鼠在手术后 1-30 天的 PWT 明显低于假手术组，在手术后 1 天达到最低（P<0.01）。电针治疗后，PWT 迅速恢复，在手术后 3、7、15 和 30 天明显高于 CCI 组（P<0.01）。与假手术组相比，CCI 手术后 NR2B 免疫反应细胞的数量明显增加（P<0.01）。与 CCI 组相比，电针刺激在术后 3、7、15 和 30 天显著减少了 NR2B 免疫反应细胞的数量（P<0.05）。在假手术组，NR2B mRNA 表达水平较低。CCI 手术后表达增加，在第 7 天迅速增加（P<0.01），在第 15 天达到峰值（P<0.01）。电针刺激后，第 15 天和第 30 天 NR2B mRNA 表达的相对量低于 CCI 组（P<0.05）。
低频电针对 CCI 大鼠模型有镇痛作用。电针的镇痛作用可能是通过抑制 NR2B 实现的。
