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[目的]观察电针预处理对角叉菜胶诱导大鼠痛记忆模型的干预效应及对脊髓背角(Spinal cord dorsal horn,SCDH)磷酸化环磷酸腺苷反应元件结合蛋白(phospharylated c AMP response element binding protein,p-CREB)的调节作用,探讨电针预处理在SCDH水平干预痛记忆的p-CREB调节机制。[方法]将30只健康雄性SD大鼠随机分为对照组、模型组和电针组(EA组),每组10只。模型组及EA组大鼠于双侧后足交叉注射角叉菜胶诱发痛记忆模型,两次注射间隔14天。分别检测造模前,首次注射后和二次注射后4h、24h、48h、72h的机械痛阈。采用免疫荧光法检测p-CREB在SCDH神经细胞中的定位表达,凝胶电泳迁移率分析实验检测大鼠SCDH水平p-CREB的DNA结合活性。[结果]首次造模前,三组大鼠双侧足跖基础痛阈无统计学差异(P>0.05)。一次造模后,与对照组比较,模型组和电针组大鼠造模同侧痛阈在模后4h至72h差异有统计学意义(P<0.01);与模型组比较,电针组同侧痛阈在模后4h差异无统计学意义(P>0.05),在24h至72h差异有统计学意义(P<0.01)。三组大鼠首次造模各时点对侧足跖痛阈差异无统计学意义(P>0.05)。二次注射后,在造模同侧,模型组与电针组大鼠造模侧足跖痛阈在二次造模后4 h至72 h差异均有统计学意义(P<0.01)。模型组与电针组比较差异无统计学意义(P>0.05)。与对照组比较,模型组大鼠二次造模对侧足跖机械痛阈在24h、48h、72h差异有统计学意义(P<0.01),EA组在72h差异有统计学意义(P<0.01)。与模型组比较,EA组大鼠在24h、48h、72h对侧足跖痛阈差异有统计学意义(P<0.01,P<0.05)。与对照组比较,模型组p-CREB阳性细胞数差异有统计学意义(P<0.01),p-CREB与GFAP的共表达差异有统计学意义(P<0.01)、与Neu N的共表达无明显变化、与OX-42的共表达差异有统计学意义(P<0.01)、p-CREB的DNA结合活性增强;与模型组比较,EA组pCREB阳性细胞数差异有统计学意义(P<0.01),p-CREB与GFAP的共表达差异有统计学意义(P<0.01)、与Neu N的共表达差异有统计学意义(P<0.01)、与OX-42的共表达差异无统计学意义(P>0.05),p-CREB的DNA结合活性减弱。[结论]电针预处理可有效减缓角叉菜胶二次注射诱导的痛记忆现象的发生,其机制可能与电针抑制SCDH星形胶质细胞p-CREB的表达和DNA结合活性有关。
[Objective] To observe the effect of electroacupuncture pretreatment on carrageenan-induced pain memory model and the effect of phospharylated cAMP response (SCDH) on spinal dorsal horn (SCDH) element binding protein, p-CREB) in order to investigate the mechanism by which electroacupuncture preconditioning regulates p-CREB in pain memory at SCDH level. [Methods] Thirty healthy male SD rats were randomly divided into control group, model group and EA group (EA group), with 10 rats in each group. Rats in model group and EA group were injected with carrageenan induced pain memory model at both sides of hind foot. The two injection intervals were 14 days. Mechanical pain thresholds were measured before modeling, after the first injection and at 4h, 24h, 48h, 72h after the second injection. The localization of p-CREB in SCDH neurons was detected by immunofluorescence. The DNA binding activity of p-CREB at the level of SCDH was detected by gel electrophoresis mobility shift assay. [Results] Before the first modeling, there was no significant difference in basal pain threshold between the two groups (P> 0.05). Compared with the control group, the pain threshold of the same side of model group and EA group was statistically significant at 4h to 72h after modeling (P <0.01). Compared with the model group, EA group There was no significant difference in the side-pain threshold at 4h after MCAO (P> 0.05), and there was a significant difference between 24h and 72h (P <0.01). There was no significant difference in contralateral paw plantarring pain threshold between the three groups at the first modeling (P> 0.05). After the second injection, there was a significant difference between model group and electroacupuncture group on the same side of modeling 4 h to 72 h after modeling (P <0.01). There was no significant difference between model group and EA group (P> 0.05). Compared with the control group, there was significant difference in mechanical pain threshold of contralateral foot plantar in model group at 24h, 48h and 72h (P <0.01), and difference of EA group at 72h was significant (P <0.01) ). Compared with model group, there was significant difference (P <0.01, P <0.05) in the threshold of contralateral pain in EA group at 24h, 48h, 72h. Compared with the control group, the number of p-CREB positive cells in the model group was significantly different (P <0.01), and the co-expression of p-CREB and GFAP was statistically significant (P <0.01) (P <0.01), and the DNA binding activity of p-CREB was increased. Compared with the model group, the number of pCREB positive cells in EA group was statistically significant (P <0.01 ), the co-expression of p-CREB and GFAP had statistical significance (P <0.01), the co-expression with Neu N had statistical significance (P <0.01), but there was no significant difference with OX-42 (P> 0.05), the DNA binding activity of p-CREB decreased. [Conclusion] EA pretreatment can effectively relieve painful memory induced by carrageenan secondary injection, which may be related to the inhibition of electro-acupuncture on the expression of p-CREB and DNA binding activity in SCDH astrocytes.