背根神经节核苷酸寡聚化域样受体3在大鼠持续性术后痛中的作用

Role of Nod-like receptor family pyrin domain-containing 3 in dorsal root ganglion in persistent postoperative pain in rats

目的评价背根神经节核苷酸寡聚化域样受体3(NLRP3)在大鼠持续性术后痛中的作用。方法取鞘内置管成功的雄性SD大鼠48只,体重200~250 g,2~3月龄,采用随机数字表法分为4组(n=12):假手术组(S组)、持续性术后痛组(P组)、持续性术后痛+NLRP3-siRNA组(P+siRNA组)和持续性术后痛+NLRP3-scrRNA组(P+scrRNA组)。通过皮肤/肌肉切口和牵拉法建立持续性术后痛模型。于术前3 d时,S组和P组鞘内注射生理盐水10μl,P+siRNA组和P+scrRNA组分别鞘内注射NLRP3-siRNA 10μl和NLRP3-scrRNA 10μl。分别于术前1 d(T0)和术后1、5、10、15、20 d(T1~5)时测定机械缩足反应阈(MWT);于T3时每组随机处死6只大鼠,取术侧L4,5节段背根神经节,采用Western blot法检测NLRP3和caspase-1的表达水平,RT-PCR法检测NLRP3 mRNA表达水平,ELISA法测定IL-1β含量。结果与S组比较,P组T2~5时MWT降低,背根神经节NLRP3及其mRNA和caspase-1的表达上调,IL-1β含量升高(P<0.05);与P组比较,P+siRNA组T2~5时MWT升高,背根神经节NLRP3及其mRNA和caspase-1的表达下调,IL-1β含量降低(P<0.05),P+scrRNA组上述指标差异无统计学意义(P>0.05)。结论背根神经节NLRP3参与了大鼠持续性术后痛的发生发展,机制可能与形成NLRP3炎症小体诱发外周神经炎症反应有关。

Objective To evaluate the role of Nod-like receptor family pyrin domain-containing 3(NLRP3)in the dorsal root ganglion(DRG)in persistent postoperative pain in rats.Methods Forty-eight male Sprague-Dawley rats,in which IT catheters were successfully implanted,weighing 200-250 g,aged 2-3 months,were divided into 4 groups(n=12 each)using a random number table method:sham operation group(S group),persistent postoperative pain group(P group),persistent postoperative pain+NLRP3-siRNA group(P+siRNA group)and persistent postoperative pain+NLRP3-scrRNA group(P+scrRNA group).A persistent postoperative pain model was established by skin/muscle incision and retraction(SMIR)in anesthetized animals.Normal saline 10μl were intrathecally injected in S group and P group,NLRP3-siRNA 10μl and NLRP3-scrRNA 10μl were intrathecally injected in CP+siRNA group and CP+scrRNA group,respectively,at 3 days before operation.The mechanical paw withdrawal threshold(MWT)was measured at 1 day before operation(T0)and 1,5,10,15 and 20 days after operation(T1-5).Six rats in each group were randomly selected and sacrificed at T3,and the L4-5 DRGs on the operated side were harvested for determination of the expression of NLRP3 and caspase-1(by Western blot),NLRP3 mRNA expression(by real-time polymerase chain reaction)and content of interleukin-1beta(IL-1β)(by enzyme-linked immunosorbent assay).Results Compared with group S,the MWT was significantly decreased at T2-5,the expression of NLRP3 protein and mRNA in DRGs was up-regulated,and the content of IL-1βwas increased in group P(P<0.05).Compared with group P,the MWT was significantly increased at T2-5,the expression of NLRP3 protein and mRNA and caspase-1 was down-regulated,and the content IL-1βwas decreased in group P+siRNA(P<0.05),and no significant change was found in the parameters mentioned above in group P+scrRNA(P>0.05).Conclusion NLRP3 in DRGs is involved in the development of persistent postoperative pain,and the mechanism may be related to the development of NLPR3 inflammasomes which further induces peripheral neuroinflammatory response in rats.