乳化七氟烷对大鼠Formalin模型脊髓水平镇痛作用的研究

Study on analgesic effects of emulsified sevoflurane on the level of spinal cord in rats with Formalin model

目的：旨在阐明不同剂量的乳化七氟烷在脊髓水平的镇痛作用及相关机制。方法：将36只成年SD大鼠,随机均分为6组,鞘内注射生理盐水50μl/kg（A1,A2）组,鞘内注射乳化七氟烷50μl/kg（B1,B2）组,鞘内乳化七氟烷25μl/kg（C1,C2）组。各组大鼠分别应用福尔马林足底注射致痛模型,通过鞘内置管至腰膨大（L4~L5）注射不同药物,应用免疫组织化学和行为学方法,综合评价乳化七氟烷在脊髓水平的镇痛效果。结果：鞘内注射乳化七氟烷可明显减少福尔马林足底致痛大鼠缩足反射的次数（P〈0.05）,明显延长缩足潜伏期（P〈0.05）,明显提高疼痛阈值（P〈0.05）,并具有一定的剂量依赖关系。光镜结果显示：鞘内注射乳化七氟烷可剂量依赖性的抑制大鼠脊髓背角I-VI层Fos蛋白的表达（P〈0.05）。结论：鞘内注射乳化七氟醚在脊髓水平能够发挥抗伤害性作用,其部分机制可能与减少大鼠脊髓背角Fos蛋白的合成有关。

Objective： To investigate the effect of different concentration of intrathecal emulsified sevoflurane administration on nociception in the rat spinal cord and its possible mechanism. Methods： Thirty-six healthy adult SpragueDawley（ SD） rats,were randomly divided into six groups： the intrathecal normal sline administration,50 μl / kg（ A1,A2） groups; the intrathecal emulsified sevoflurane administration,50 μl / kg（ B1,B2） groups; the intrathecal emulsified sevoflurane administration,25 μl / kg（ C1,C2） groups,six animals for each group. The model of injection of formalin into hindpaw of rats which produced pain was used. Then,the pain behavioral approach and immunohistochemistry technique was used to evaluate different concentration of intrathecal emulsified sevoflurane administration on nociception in the rat spinal cord. Results： The intrathecal emulsified sevoflurane can inhibit the flinching induced by formalin,prolong the rat＇s paw withdrawal latency forheat stimuli and increase the rat＇s paw withdrawal threshold for mechanical stimuli（ P〈0. 05）,which was with a dose-dependent manner. We also found intrathecal emulsified sevoflurane can inhibit Fos protein expression in the dorsal horn of spinal cord also with a dose-dependent manner（ P〈0. 05）.Conclusion： Intrathecal administration of emulsified sevoflurane exert anti-nociceptive effects at the spinal level by inhibiting Fos protein expression in the dorsal horn of spinal cord of rats.