脊髓G蛋白偶联受体激酶2在持续性术后痛中的表达变化

Changes of spinal G protein-coupled receptor kinase 2 (GRK2) expression in persistent postoperative pain in rats

目的观察脊髓G蛋白耦联受体激酶2(GRK2)在大鼠持续性术后痛中的表达变化。方法雄性SD大鼠40只,按随机数字表法将大鼠分为2组(n=20):假手术组和皮肤/肌肉切口和牵拉模型组(SMIR组);采用Flatters法制备大鼠SMIR模型;分别于术前1 d(T_0),术后3 (T_1)、7 d(T2)、14 d(T3)、21 d(T4)用von Frey细丝法测定机械缩足反应阈值(MWT);在相应时间点行为学测定后随机抽取4只大鼠处死,取L_4～L_6节段脊髓组织,Western blot法检测脊髓GRK2表达。结果 T_(1～4)时,SMIR组MWT较T_0时明显下降,脊髓GRK2蛋白表达较T_0时明显下调(P均<0. 05);与假手术组比较,SMIR组在T_(1～4)时MWT和脊髓GRK2蛋白表达较低,差异均有统计学意义(P <0. 05)。结论脊髓GRK2表达水平下调与大鼠SMIR持续性术后痛的发生、发展有关。

Objective To investigate the change of spinal G protein-coupled receptor kinase 2 （GRK2） expression in persistent postoperative pain evoked by skin/muscle incision and retraction （SMIR） in rats. Methods 40 male Sprague Dawley （SD） rats were divided into 2 groups （ n = 20） using a random number table ： sham operation group and skin/muscle incision and retraction group （ SMIR group）. A rat model of peristent postoperativepain evoked by SMIR was made according to the method described by Flat- ters. Pain behavior was assessed by paw mechanical withdrawal threshold （MWT） to von Frey filament stimulationintensity at 1 d before operation （ T0 ） and 3 d （ T1 ）, 7 d （ T2 ）, 14 d （ T3 ） and 21 d （ T4 ） after operation. 4 rats in each group were sacrificed at T0 -4, the L4-L6 segments of the spinal cord were obtained for determination of GRK2 expression in the spinal cord by Western blot. Results Compared with To, the MWT was significantly decreased and the expression of spinal GRK2 was down-regulated at T1 -T4 in SMIR group （ P 〈 0. 05 ）. Compared with sham operation group, the MWT and the expression of spinal GRK2 was decreased at T1 -T4 in SMIR group （ P 〈 0.05 ）. Conclusions The down-regulation of expression of spinal GRK2 may be involved in the development and maintenance of persistent postoperative pain in rats evoked by SMIR.