右旋美托咪啶对切口痛大鼠脊髓背角神经元型一氧化氮合酶和P物质mRNA表达的影响  

Effect of dexmedetomidine on spinal neuronal nitricoxide synthase and substance P mRNA expression in rat model of incisional pain

作　　者：刘春芳[1] 姜虹[1] 

机构地区：[1]上海交通大学医学院附属第九人民医院麻醉科,200011

出　　处：《上海医学》2009年第6期483-486,共4页Shanghai Medical Journal

摘　　要：目的探讨右旋美托咪啶(Dex)对切口痛大鼠的镇痛作用,以及对脊髓背角神经元型一氧化氮合酶(nNOS)和P物质(SP)mRNA表达的影响。方法雄性Wistar大鼠24只,体重250～300g,随机分为4组,每组6只。S组为假手术组,O组为手术对照组,D1组为Dex30μg/kg组,D2组为Dex50μg/kg组。O组、D1组和D2组在大鼠左后爪作一纵形切口制备切口痛模型,D1组和D2组于术前10min腹腔注射Dex,S组和O组腹腔注射0.9%氯化钠溶液1mL。术后2h以累积疼痛评分(CPS)和机械刺激缩足阈值(PWT值)评估疼痛强度。逆转录-聚合酶链反应检测脊髓背角nNOS、SP mRNA的表达。结果O组和D1组大鼠术后的CPS较本组术前显著升高(P值均<0.05),PWT值较本组术前显著降低(P值均<0.05)。术后O组大鼠的CPS显著高于其他3组(P值均<0.05),PWT值显著低于其他3组(P值均<0.05)。术后D2组大鼠的CPS显著低于D1组(P<0.05),PWT值显著高于D1组(P<0.05),与S组的差异均无统计学意义(P值均>0.05)。O组的nNOS及SP mRNA的相对表达量均显著高于其他3组(P值均<0.05),D1组的nNOS及SP mRNA的相对表达量均显著高于D2组和S组(P值均<0.05)。结论Dex对切口痛大鼠有明显镇痛作用,且随剂量增大而增强,其镇痛作用可能与其抑制脊髓背角nNOS、SP mRNA的表达有关。Objective To investigate the analgesic effect of dexmedetomidine on rat model of incisional pain and the expression of neuronal nitricoxide synthase （nNOS） and substance P （SP） in the spinal cord. Methods Twenty-four adult male Wistar rats weighing 250-300 g were randomly divided into four groups with six rats in each groups： group S was sham operation group, group O was operation control group, group D1 received 30 μg/kg dexmedetomidine, and group D2 received 50 μg/kg dexmedetomidine. All groups were given corresponding drugs 10 min pre-operation. The rats received longitudinal incision in the left hindpaw to establish pain model. The cumulative pain score （CPS） and paw withdrawal threshold （PWT） were measured in each group to evaluate the pain magnitude. Reverse transcriptase-polymerase chain reaction （RT-PCR） was used to examine nNOS and SP expression in the spinal cord. Results The CPS in group O and D1 were significantly increased and MWT were significantly decreased after operation compared with those before operation （P〈0.05）. The CPS in group O was significantly higher and the MWT was significantly lower than those of the other 3 groups after operation （P〈0.05）. The CPS in group D2 was significantly lower and MWT was significantly higher than those of group D1 after operation （P〈0.05）, and there was no significant difference between D2 and group S. The expression of nNOS and SP mRNA was significantly higher than that of the other 3 groups （ P〈0.05）, and that of group D, was significantly higher than that of group D2and S （P〈0.05）. Conclusion Dexmedetomidine has an obvious analgesic effect on incisional pain in rats and the effect increases with the dose of Dexmedetomidine. The analgesic effect Dexmedetomidine is possibly related to the decrease of nNOS and SP mRNA in the spinal cord.

关 键 词：右旋美托咪啶 切口痛 Α2肾上腺素能受体激动剂 神经元型一氧化氮合酶 P物质 

分 类 号：R96[医药卫生—药理学] R402[医药卫生—药学]