电针对坐骨神经慢性压迫性损伤大鼠脊髓氨基酸类递质水平的影响

Effect of Electroacupuncture on the Levels of Amino Acid Neurotransmitters in the Spinal Cord in Rats with Chronic Constrictive Injury

目的:通过观察神经病理性痛大鼠脊髓相应节段氨基酸类递质水平的变化及电针对其的影响,探讨电针干预神经病理性痛的脊髓机制。方法:雄性SD大鼠,随机分为4组(n=10):空白组、假手术组、模型组、电针组。采用坐骨神经慢性压迫性损伤(CCI)法制备神经病理性痛模型。电针组电针刺激大鼠损伤侧"委中"穴与"环跳"穴30 min,1次/d,共7 d。测定手术后第10、16天机械痛阈和热痛阈;以OPA柱前衍生法+HPLC荧光检测法测定脊髓相应节段谷氨酸(Glu)、天冬氨酸(Asp)、谷氨酰胺(Gln)、γ-氨基丁酸(GA-BA)、甘氨酸(Gly)和牛磺酸(Tau)水平的变化。结果:与基础值比较,模型组和电针组CCI后第10天机械痛阈和热痛阈降低(均P<0.01);与CCI后10 d比较,电针组CCI后16 d时机械痛阈和热痛阈均升高(P<0.01)。与假手术组比较,模型组机械痛阈和热痛阈降低(P<0.01),脊髓相应节段Glu、Asp、Gln和GABA水平均升高(P<0.05,P<0.01),Gly和Tau的水平则降低(P<0.05);与模型组比较,电针组CCI后16 d机械痛阈和热痛阈升高(P<0.01),脊髓相应节段Glu、Asp、Gln、Gly和Tau的水平均被逆转(P<0.01,P<0.05),GABA的水平则进一步升高(P<0.01)。结论:电针减轻大鼠神经病理性痛的机制可能与有效地减少脊髓兴奋性氨基酸递质的释放、促进抑制性氨基酸递质的释放有关。

Objective To observe the changes of amino acid neurotransmitter contents in the lumbar spinal cord after electroacupuncture（EA） in rats with neuropathic pain so as to study its spinal mechanism underlying pain relief.Methods Forty SD rats were randomly divided into control,sham surgery,model and EA groups（n=10）.Chronic constrictive injury（CCI）（neuropathic pain） model was duplicated by ligature of the right sciatic nerve with a piece of catgut.EA（1-3 mA,2 Hz） was applied to ＂Huantiao＂（GB 30） and ＂Weizhong＂（BL 40） on the injured side for 30 minutes,once a day for 7 days.The mechanical and thermal pain thresholds were measured before and after CCI,and after EA intervention.Concentrations of glutamate（Glu）,aspartate（Asp）,glutamine（Gln）,γ-aminobutyric acid（GABA）,Glycine（Gly） and taurine（Tau） in the lumbar spinal cord（L4-6） were detected by O-phthaladehyde derivatization ＋ high performance liquid chromatography（HPLC）.Results Compared with the control group,both the mechanical and thermal pain thresholds of the model group were decreased significantly on day 10 and day 16 after CCI（P0.01）.Compared with the model group,the mechanical and thermal pain thresholds in the EA group on day 16 after CCI were upregulated strikingly（P0.01）.In comparison with the control group,Glu,Asp,Gln and GABA levels in the lumbar spinal cord were significantly higher in the model group（P0.05,P0.01）,while Gly and Tau levels in the lumbar spinal cord were markedly lower in the model group（P0.05）.In comparison with the model group,spinal Glu,Asp,and Gln contents were downregulated significantly in the EA group（P0.01）,while Gly,GABA and Tau levels were upregulated obviously（P0.01,P0.05）.No significant differences were found between the control and sham surgery groups in the mechanical and thermal pain thresholds,and in the spinal Glu,Asp,Gln,GABA,Gly and Tau levels（P0.05）.Conclusion EA of GB 30 and BL 40 may alleviate neuropathic pain in CCI rats,which is closely with its effects in reducing the release of excitatory amino acids and promoting the release of inhibitory amino acid neurotransmitters.