皮内注药对急性内脏炎症痛大鼠抗伤害作用的研究

Antinociceptive effects of intradermal drugs injection on acute visceral inflammatory pain in rats

目的在动物模型上研究皮内注药对内脏炎症痛的抗伤害作用及对其机制进行初步探讨。方法大鼠乙状结肠壁粘膜下定量注射福尔马林(5%,0.1 m l)制作急性内脏炎症痛模型,观察大鼠行为学表现并进行评分。分别在实验区(直肠、乙状结肠相应的脊神经体表分布区)及实验区外(远离直肠、乙状结肠相应的脊神经体表分布区)皮内多点注射0.125%、0.25%利多卡因或生理盐水,进行疼痛学评分;在利多卡因皮内注射组,采用高效液相色谱法测定血浆利多卡因浓度。结果福尔马林注射组同皮内注药组在第一个时间段内疼痛分数差异无显著性(P>0.05)。在实验区皮内注射0.25%利多卡因和生理盐水均能减轻内脏痛反应(P<0.01),而0.125%利多卡因皮内注射对疼痛分数同福尔马林致炎组相比差异无显著性(P>0.05);在实验区外唯有0.25%利多卡因皮内注射有抗伤害效应。皮内注射0.25%利多卡因的血浆浓度高于0.125%利多卡因组(P<0.01)。结论在内脏致痛器官的脊神经体表分布区皮内注射可降低动物的痛行为学评分,其作用可能与药物经皮内吸收入血和局部刺激激活末梢感受器有关。

Aim To explore whether intradermal drugs injection can have antinociceptive effects on acute visceral inflammatory pain induced by formalin and its mechanism in rats. Methods An acute local visceral pain model was produced by sigmoid submucosal injection of formalin （0. 1 ml, 5 % ）, a pain score of the formalin-induced behaviors was undertaken to confirm the success of the model and then carried out intradermal lidocaine （0. 25 %, 0. 125 % ） or isotonic saline injection both into and out of experimental area （the distributed area of spinal nerves of the painful organs）. Among intradermal lidocaine injection groups, the concentrations of lidocaines in blood were determinated using high performance liquid chromatography （HPLC）. Results There was no significance of pain scores in the first time point among seven groups （P 〉 0. 05 ）. Inside experimental area, pain scores were decreased in both intradermal 0. 25% lidocaine and saline injection group （ P 〈 0. 01 ） instead of 0. 125% lidocaine injection group. Outside experimental area, intradermal 0. 25% lidocaine-injection showed analgesic effect rather than 0. 125% lidocaine and saline. In addition, the concentration of 0.25% lidocaine in blood was higher than 0. 125 % lidocaine（P 〈0.01 ）. Conclusion Intradermal-injection in the distributed skin area of spinal nevers of the painful organs showes antinociceptive effects, which may involve the mechanisms of activation of receptors via local stimulus to the skin area and lidocaine absorption.