大鼠坐骨神经损伤性疼痛的行为观察和背根神经节中Kv1mRNA的表达

The decrease of Kv1mRNA expression in dorsal root ganglion in rats

目的:探讨坐骨神经慢性压迫性损伤(CCI)大鼠背根神经节(dorsal root ganglion,DRG)钾通道Kv1mRNA的表达及其在疼痛发生机制中的作用。方法:SD雄性大鼠60只,随机分为:A组:CCI组(30只);B组:对照组(30只)。术前及术后3,7,14,28天分别测定大鼠热痛阈值、机械痛阈值和行为学评分。术后3、7、14、28天用RT-PCR分析Kv1mRNA表达的变化。结果:所有CCI动物从术后3天起,出现明显疼痛行为学改变和热痛、机械痛阈值的降低,与对照组比较差异有显著性(P<0.05或P<0.01)。RT-PCR结果显示A组术后3天Kv1.2,Kv1.4,Kv1.6mRNAs明显减少,术后7天Kv1.1mRNAs明显减少,显著低于B组(P<0.05或P<0.01),术后Kv1.5mRNAs均无减少(P>0.05)。结论:慢性坐骨神经损伤后,背根神经节钾通道Kv1.1,Kv1.2,Kv1.4mRNAs的表达减少,而且表达减少与CCI大鼠的痛过敏、行为变化在时相上基本一致,说明CCI大鼠痛觉过敏与背根神经节Kv1.1,Kv1.2,Kv1.4mRNAs表达的减少有关。

Objective：To observe the expressive variety of KvlmRNA in dorsal root ganglion on neuropathic pain by chronic constriction injury （CCI）. Methods：Sixty male Sprague-Dawley rats were randomly divided into two groups：CCI group and control group, Recording the responsiveness to mechanical and thermal stimuli before and after sciatic nerve constriction injury.For hemi-quantitative analysis,RT-PCR method was used in the detection of the levels of KvlmRNA in dorsal root ganglion at the 3th,7th, 14th,28th day following sciatic nerve constriction injury.Results：The rats＇ responsiveness to mechanical and thermal stimuli and pain behavior were significandy increased on postoperative days after sciatic nerve ligation compared with preoperative condition （P〈0.05）. Electrophoresis of the RT-PCR products showed that the relative expression levels of the Kvl.2,1.4,1.6mRNA were obviously declined at 3 days and Kv1.1mRNA was obviously declined at 7 days following CCI （P〈0.01）. No significant changes in Kv1.5mRNA levels were detectable at any day. Conclusion：The CCI rats＇ sensitivity to thermal and mechanical stimuli was significantly increased following sciatic nerve constriction injury.This could be related to the downregulation of Kv1mRNA expression in dorsal root ganglion.