鞘内注射可乐定对切口痛大鼠脊髓背角PKA催化亚单位表达的影响

目的:观察鞘内注射(intrathecal injection IT)可乐定对切口痛大鼠脊髓背角PKA催化亚单位表达的影响.方法:选择鞘内置管成功的雄性SD大鼠80只,随机分为5组,每组16只,分别为假手术组,对照组,可乐定5μg组,可乐定10μg组和可乐定20μg组.按Yaksh法鞘内置管,按Brennan法制作大鼠...

Effect of intrathecal Clonidine on Expression of Protein Kinase A Catalytic Subunit in the Spinal Dorsal Horn in a Rat Model of Incisional Pain

Objective：To observe the effect of intrathecal clonidine on expression of protein kinase A （PKA） catalytic subunit in the spinal dorsal horn in a rat model of incisional pain. Methods：80 male Spragne -Dawley rats were divided randomly into five groups： sham group, control group, pre - incisional clonidine 5ug group, pre - incisional clonidine 10μg group and pre - ineisional clonidine 20ug group. Intrathecal catheter and the model of incisional pain were produced according to Yaksh and Brennan＇s described respectively. Changes of pain behavior were assessed by mechanical withdrawal threshold （MWT） and thermal withdrawal latency（TWL）. The expressions of PKA catalytic subunit in the spinal dorsal horn were assessed by immunohistechemical method and western blot analysis. Results： Compared with sham group, MWT and TWL in control group were decreased significantly at 3h after incision （ P 〈 0. 01 ）and the number of positive ceils and protein expres- sion of PKA catalytic subunit in the spinal dorsal horn were increased significantly in control group （ P 〈 0. 01 ）. Compared with control group,MWT and TWL in pre - incision clonidine 10ug group and pre -incision elonidine 20p, g group were in- creased significantly at 3h after incision（ P 〈0. 01 ） and pre - incision clonidine 20p,g group were most increased than any oth- er groups（ P 〈 0. 01 ）. Dose - effect analysis demonstrated that the anfinociceptive effect of intrathecal clonidlne was positively dose - related. The number of positive cells and protein expression of PKA catalytic subunit in the spinal dorsal horn were decreased significantly in pre - incision clonidine 10ug group and pre - incision clonidine 20pg group and pre - incision eloni- dine 20μg group were most decreased than any other groups（ P 〈0. 01 ）. However,MWT , TWL,the number of positive cells and protein expression of PKA catalytic subunit in the spinal dorsal horn changed with no statistical significance in pre - incisional donidinc 5ug group compared with control group. Conclusion：In a rat model of postoperative pain, pro - eruptive intrathecal Clonidine provided obviously dose - related antinociceptivc effect,which might be associated with inhibition of the increased expression of PK A catalytic subunit in spinal cord caused by incisional pain.