桔梗皂苷D对大鼠神经病理性疼痛及脊髓小胶质细胞活化的影响

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（SN...

Effects of platycodin D on neuropathic pain and spinal microglia activation in rats

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=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 L5 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)-1βand IL-6 were detected by enzyme-linked immunosorbent assay(ELISA).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(P<0.05);the expression of Iba-1,TNF-α,IL-6 and IL-1βremarkably increased in the spinal dorsal horn of rats in group SNL 7 days after surgery(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(P<0.05);the expression of Iba-1,TNF-α,IL-6,and IL-1βin the spinal cord of rats in group PDm significantly decreased 7 days after surgery(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(P<0.05).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-1βthrough inhibition of spinal microglia activation in rats.