论文部分内容阅读
目的:探讨桔梗皂苷D（platycodin D, PD）对大鼠神经病理性疼痛模型的镇痛作用及其对脊髓小胶质细胞活化的影响。方法:将60只雄性成年SD大鼠按随机数字表法分为6组（每组10只）：假手术组（Sham组）、脊神经结扎（spinal nerve ligation, SNL）组（SNL组）、SNL+生理盐水组（SNL+NS组）、SNL+PD低剂量组（PDl组）、SNL+PD中剂量组（PDm组）、SNL+PD高剂量组（PDh组）。SNL大鼠结扎和剪断左Ln 5脊神经，Sham组大鼠只分离神经不进行结扎剪断处理；SNL+NS组、PDl组、PDm组和PDh组大鼠于造模后当天开始分别经口灌胃生理盐水或PD（1、5、10 mg/kg）至术后7 d。分别于术前1 d和术后1、3、5、7、10、14 d测定各组大鼠机械刺激缩足反射阈值（paw mechanical withdrawal threshold, PMWT）和热刺激缩足反射潜伏期（paw withdraw thermal latency, PWTL）。于术后7 d取大鼠脊髓，采用免疫荧光和Western blot法检测脊髓小胶质细胞离子钙接头蛋白分子1（ionized calcium-binding adaptor molecule1, Iba-1）的表达，ELISA法检测脊髓促炎症细胞因子TNF-α、IL-1β和IL-6的含量变化。n 结果:与Sham组比较：SNL组、SNL+NS组、PDl组、PDm组和PDh组大鼠术侧PMWT于术后1、3、5、7、10、14 d明显降低，术侧PWTL于术后3、5、7、10、14 d明显降低（n P<0.05）；术后7 d SNL组大鼠脊髓Iba-1的表达和TNF-α、IL-6、IL-1β含量均明显升高（n P<0.05）。与SNL+NS组比较：PDm组、PDh组大鼠术后3、5、7、10、14 d术侧PMWT升高（n P<0.05），PDm组大鼠术后5、7、10、14 d术侧PWTL升高（n P<0.05）；术后7 d PDm组大鼠脊髓Iba-1的表达和TNF-α、IL-6、IL-1β含量均明显降低（n P<0.05）。与PDm组比较，PDl组和PDh组大鼠术侧PMWT于术后3、5、7、10、14 d降低，术侧PWTL于术后5、7、10、14 d降低（n P<0.05）。n 结论:PD能够缓解SNL大鼠的机械痛敏和热痛敏，其作用机制可能与其抑制大鼠脊髓小胶质细胞活化，进而减少炎性细胞因子TNF-α、IL-6和IL-1β的含量有关。“,”Objective:To investigate the analgesic effects of platycodin D (PD) on neuropathic pain in rats and PD's effects on spinal microglia activation.Methods:According to the random number table method, 60 male SD rats were divided into six groups (n n=10): a sham group (group Sham), a spinal nerve ligation (SNL) group (group SNL), a SNL+normal saline group (group SNL+NS), a SNL+low-dose PD group (group PDl), a SNL+medium-dose PD group (group PDm), and a SNL+high-dose PD group (group PDh). Rats in group SNL were subjected to ligation and cutting of the Ln 5 spinal nerve, while those in group Sham underwent nerve separation without ligation. Meanwhile, groups SNL+NS, PDl, PDm and PDh were orally administered with normal saline or PD (1, 5 and 10 mg/kg) on the day of modeling until 7 days after surgery. Then, the paw withdraw thermal latency (PWTL) and paw mechanical withdrawal threshold (PMWT) were measured 1 day before surgery and 1, 3, 5, 7, 10 and 14 days after surgery. Then, their spinal cords were collected 7 days after surgery. The expression of ionized calcium-binding adaptor molecule 1 (Iba-1) in spinal microglia was detected by immunofluorescence and Western blot. The changes in the content of proinflammatory factors such as tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 were detected by enzyme-linked immunosorbent assay (ELISA).n Results:Compared with group Sham, remarkable decreases were found in PMWT in groups SNL, SNL+NS, PDl, PDm and PDh 1, 3, 5, 7, 10 and 14 days after surgery, as well as in PWTL 3, 5, 7, 10 and 14 days after surgery (n P<0.05); the expression of Iba-1, TNF-α, IL-6 and IL-1β remarkably increased in the spinal dorsal horn of rats in group SNL 7 days after surgery (n P<0.05). Compared with group SNL+NS, the PMWT on the affected side significantly increased in groups PDm and PDh 3, 5, 7, 10 and 14 days after surgery, and the PWTL on the affected side significantly increased in group PDm 5, 7, 10 and 14 days after surgery (n P<0.05); the expression of Iba-1, TNF-α, IL-6, and IL-1β in the spinal cord of rats in group PDm significantly decreased 7 days after surgery (n P<0.05). Compared with group PDm, groups PDl and PDh presented remarkable decreases in PMWT on the affected side 3, 5, 7, 10 and 14 days after surgery, and in PWTL on the affected side 5, 7, 10 and 14 days after surgery (n P<0.05).n Conclusions:PD can alleviate mechanical and thermal hyperalgesia in SNL rats, which may be associated with reduced levels of TNF-α, IL-6 and IL-1β through inhibition of spinal microglia activation in rats.