鞘内注射氯胺酮对内脏痛大鼠远位触液神经元Fos蛋白表达的影响

Effect of intrathecal injection of ketamine on expression of Fos protein in the distal cerebrospinal fluid contacting neuron in rat with visceral pain

目的观察鞘内注射氯胺酮对内脏痛大鼠远位触液神经元(dCSF-CN)Fos蛋白表达的影响。方法 SD大鼠侧脑室注射霍乱毒素亚单位B与辣根过氧化物酶复合物(CB-HRP)示踪标记dCSF-CN。48h后氯胺酮(K)组(n=10)鞘内注射氯胺酮50μg,人工脑脊液(C)组(n=10)鞘内注射等体积人工脑脊液。两组均在乙状结肠壁注射甲醛制作内脏痛模型。进行各时间点疼痛学评分,免疫组织化学法检测Fos蛋白在dCSF-CN中的表达。结果与C组相比,K组大鼠各时间点疼痛学评分降低(P<0.01),dCSF-CN中Fos蛋白表达下降(P<0.01)。K组未见CB-HRP/Fos双标记神经元。结论鞘内注射氯胺酮可以降低大鼠内脏痛反应,减少dCSF-CN中Fos蛋白的表达。

Objective To investigate the effect of intrathecal injection of ketmine on expression of Fos protein in the distal cerebrospinal fluid contacting neurons（dCSF-CNs） in rat with visceral pain.Methods The dCSF-CNs were traced by injection of cholera toxin subunit B with horseradish peroxidase（CB-HRP） into lateral ventricle of SD rats.Fourty-eight hours later,the rats were given intrathecal injection of ketamine 50 μg（group K,n=10） or the same volumn of artificial cerebrospinal fluid（group C,n=10）.The rat model of visceral pain was made by injection of formalin into sigmoid wall in two groups.The pain scores at each time point were recorded and the CB-HRP/Fos double-labeling method was used to observe the expression of Fos protein in dCSF-CNs.Results Compared with group C,the pain scores and expression of Fos protein in dCSF-CNs were lower in group K（P0.01）.No CB-HRP/Fos double-labeling neuron was observed in group K.Conclusion Intrathecal pretreatment with ketamine can suppress visceral pain induced by injection of formalin into sigmoid wall and down-regulate the expression of Fos protein in dCSF-CNs.