Objective: To observe the effect of electroacupuncture (EA) of Governor Vessel (GV) on the expressions of glutamate decarboxylase 67 (GAD67) and γ-aminobutyric acid transaminase (GABA-T) in the cerebral cortex of rats with post-stroke limb spasticity, so as to explore its mechanism underlying improvement of limb spasticity.
Methods: Twenty four male SD rats were randomly and equally divided into control, sham operation, model, and EA groups. The cerebral ischemia model was established by occlusion of the middle cerebral artery (MCAO). EA (100 Hz, 1-3 mA) was applied to "Dazhui"(GV14), "Jizhong"(GV6) and "Houhui"( anteromedial of transverse process of the sixth lumbar vertebra) for 30 min, once daily for 7 consecutive days. The neurologic deficit score (0-5 points) was evaluated according to Zea Longa's method, and the muscular tension severity (0-5 points) was assessed according to the modified Ashworth muscle tone rating scale, and the tension signals of the quadriceps ferroris of the affected limb were recorded using tonotransducer and BL-420F electrophysiological recorder. The expression levels of GAD67 and GABA-T proteins and mRNAs in the cerebral cortex were detected by immunohistochemistry, fluorescence quantitative real-time PCR and Western blot, separately.
Results: After modeling, the neurological deficit score, muscle tone score, and the expression levels of GABA-T mRNA and protein in cerebral cortex were significantly increased (P<0.01, P<0.05), tension signal value and the expression levels of GAD67 mRNA and protein in cerebral cortex were significantly decreased (P<0.01) in the model group relevant to the control and sham operation groups. Following the intervention, the neurological deficit score, muscle tone score, and expression levels of GABA-T mRNA and protein in cerebral cortex were significantly decreased (P<0.01), tension signal value and the expression levels of GAD67 mRNA and protein in cerebral cortex were significantly increased (P<0.01, P<0.05) in the EA group in contrast to the model group.
Conclusion: EA stimulation of Governor Vessel can ameliorate the limb spasticity symptom in MCAO rats, which may be associated with its functions in increasing the expressions of GAD67 protein and mRNA and inhibiting the expressions of GABA-T protein and mRNA, thereby playing the inhibitory role of GABA.
目的：观察督脉电针对脑卒中后肢体痉挛大鼠大脑皮层中谷氨酸脱羧酶67(GAD67)和γ-氨基丁酸转氨酶(GABA-T)表达的影响, 探讨督脉电针改善脑卒中后肢体痉挛的可能机制。方法：SPF级健康雄性SD大鼠随机分为空白组、假手术组、模型组和电针组, 每组6只。采用线栓法制备大脑中动脉阻塞（MCAO）大鼠模型。电针组给予“大椎”“脊中”“后会”电针治疗, 每次30 min, 1次/d, 连续7 d。评估各组大鼠治疗前后神经功能缺损评分, 以改良Ashworth评分和肌张力评估大鼠治疗前后肌痉挛水平, 免疫组织化学法、实时荧光定量PCR法和Western blot法检测大鼠大脑皮层中GAD67和GABA-T蛋白和mRNA的表达情况。结果：与同时点空白组、假手术组比较, 模型组大鼠神经功能缺损评分、改良Ashworth评分及大脑皮层GABA-T mRNA、蛋白表达水平均显著升高(P<0.01, P<0.05), 张力信号值及大脑皮层中GAD67 mRNA、蛋白表达水平均显著降低(P<0.01)。与同时点模型组比较, 电针组大鼠神经功能缺损评分、改良Ashworth评分及大脑皮层中GABA-T mRNA、蛋白表达水平均降低(P<0.01), 张力信号值及大脑皮层中GAD67 mRNA、蛋白表达水平均显著升高(P<0.01, P<0.05)。结论：督脉电针可升高MCAO大鼠大脑皮层中GAD67蛋白及mRNA的表达水平, 同时降低GABA-T蛋白及mRNA的表达水平, 发挥抑制性神经递质γ-氨基丁酸的功能, 从而改善脑卒中后肢体痉挛症状。.
Keywords: Electroacupuncture; Glutamate decarboxylase 67; Muscular tension; Post-stroke limb spasticity; γ-aminobutyric acid (GABA); γ-aminobutyric acid transaminase.