脊髓Toll样受体4在大鼠持续性术后痛形成中的作用

Role of Toll.like receptor 4 in spinal cord in a rat model of persistent postoperative pain evoked by skin/ muscle incision and retraction

目的探讨脊髓Toll样受体4（11LR4）在大鼠持续性术后痛中的作用。方法雄性sD大鼠96只，体重200—250g，采用随机数字表法，将其随机分为4组（n=24）：假手术组（I组）、持续性术后痛模型组（Ⅱ组）、SMIR＋鞘内阴性对照siRNA组（Ⅲ组）和SMIR＋鞘内TLR4siRNA组（Ⅳ组）。采用Flatters法建立大鼠持续性术后痛模型，Ⅰ组和Ⅱ组于术前1d和术后1～6d鞘内注射人工脑脊液20μl，1次／d；lU组和Ⅳ组于术前1d和术后1～6d分别鞘内注射8cranlblesiRNA10μl＋人工脑脊液10μl和TLR4siRNA 10μl＋人工脑脊液10μl，1次，d。于术前1d，术后1、3、7、12、22d时测定机械性痛阈（MWT），采用Westernblot法测定脊髓11LR4蛋白表达。结果与I组比较，Ⅱ组和Ⅲ组术后3、7、12、22d时MWT降低，Ⅱ组和Ⅳ组术后3、7、12d时MWT降低，Ⅱ组和Ⅲ组术后3、7、12d时脊髓TLR4蛋白表达上调（P〈0．05）；与Ⅱ组比较，Ⅳ组术后3、7、12d时MWT升高，脊髓TLR4蛋白表达下调（P〈0．05）。结论脊髓TLR4参与了大鼠持续性术后痛的形成。

Objective To investigate the role of Toll-like receptor 4 （TLR4） activation in spinal cord in a rat model of pemistent postoperaiive pain evoked by skin/muscle incision and retractian（SMIR）. Methods Ninety- six male SD rats weighing 200-250 g were randomly divided into 4 groups（ n = 24 each） ： group sham operation; group SMIR; group SMIR ＋ IT scramble siRNA and group SMIR ＋ IT TLR4siRNA. The rat model of persistent postoperative pain evoked by SMIR was established according to the method described by Flattem. The TLR4 siR- NA were administered intrathecaUy for 7 days starting from 1 day before surgery. Pain behavior was assessed by paw mechanical withdraw threshold （MWT） to Electronic yon Frey Anesthesiometer stimulation at 1 day before and 1, 3,7,12, and 22 days after operation. Four animals were sacrificed at each time point in each group for detection of the expression of TLR4 protein in the spinal cord by Western blot analysis. Results Compared to group sham group, MWT was significantly descreased at 3, 7, 12, and 22 days after operation, while the expression of TLR4 protein in the spinal cord were significantly increased at 3, 7, 12 days after operation in group SMIR and group SMIR ＋ IT scramble siRNA ; IT TLR4siRNA significantly attenuated the hyperalgesia induced by SMIR and de- screased the expression of TLR4 protein at 3, 7, 12 days after operation in group SMIR ＋ IT TLR4siRNA. Conclu- sion TLR4 activation in spinal cord plays an important role in the development of SMIR-evoked persistent postop- eratlve pare in rats