姜黄素对利多卡因诱导大鼠神经损伤的影响:Akt和ERK 1/2信号通路在其中的作用

Effect of curcumin on lidocaine-induced nerve injury in rats:the role of Akt and ERK1/2 signaling pathway

目的评价姜黄素对利多卡因诱发大鼠神经损伤的影响及蛋白激酶B(Akt)和细胞外信号调节激酶1/2(ERK1/2)信号通路在其中的作用.方法SPF级雄性SD大鼠80只,8~10周龄,体重220~250g,采用随机数字表法分为8组(n=10):对照组(C组)、假手术组(S组)、利多卡因组(L组)、二甲基亚砜(DMSO)组(D组)、姜黄素低剂量组(CL组)、姜黄素高剂量组(CH组)、姜黄素+ERK抑制剂PD98059组(P组)和姜黄素+Akt抑制剂MK-2206组(M组).除C组和S组外,其余6组行鞘内置管,注射2%利多卡因10μl制备利多卡因诱发神经损伤模型.于鞘内置管后第3天开始,连续14d,采用微导管注射给药:D组、CL组和CH组分别注射DMSO10μl、姜黄素100μg∕10μl及姜黄素500μg∕10μl,1次∕d;P组和M组注射姜黄素500μg∕10μl,1次∕d,分别腹腔注射D9805910μg和MK-220612μg,均溶于5μlDMSO溶液,每周给药1次.于鞘内置管前1d、鞘内置管后第3天给药前、给药第14天时测定术侧后肢机械缩足反应阈(MWT)和热缩足潜伏期(TWL).给药结束后第1天,取脊髓组织,采用Westernblot法检测脊髓ERK1∕2、磷酸化ERK1∕2(p-ERK1∕2)、Akt、磷酸化Akt(p-Akt)、c-fos、Bcl-2、Bax表达水平;采用Real-timePCR法检测脊髓ERK1∕2和Akt的mRNA表达水平.结果与C组比较,L组MWT降低,TWL缩短,ERK1∕2及其mRNA、p-ERK1∕2、c-fos、Akt及其mRNA、p-Akt、Bcl-2表达下调,Bax表达上调(P<0.05);与L组比较,CL组、CH组、P组和M组MWT升高,TWL延长,CL组和CH组p-ERK1∕2、c-fos、p-Akt、Bcl-2表达上调,Bax表达下调,P组p-Akt、Bcl-2表达上调,Bax表达下调,M组p-ERK1∕2、c-fos表达上调(P<0.05);与CH组比较,P组和M组MWT降低,TWL缩短,P组脊髓p-ERK1∕2、c-fos表达下调,M组脊髓p-Akt和Bcl-2表达下调,Bax表达上调(P<0.05).结论姜黄素可减轻利多卡因诱发的大鼠神经损伤,部分机制可能与增强Akt和ERK1∕2信号通路活性有关.

Objective To evaluate the effect of curcumin on lidocaine-induced nerve injury and the role of protein kinase B(Akt)and extracellular signal-regulated kinase 1/2(ERK1/2)signaling pathway in rats.Methods Eighty SPF male Sprague-Dawley rats,aged 8-10 weeks,weighing 220-250 g,were divided into 8 groups(n=10 each)using a random number table method:control group(group C),sham operation group(group S),lidocaine group(group L),dimethyl sulfoxide(DMSO)group,low-dose curcumin group(group CL),high-dose curcumin group(group CH),curcumin plus ERK inhibitor PD98059 group(group P)and curcumin plus Akt inhibitor MK-2206 group(group M).The model of nerve injury was established by injecting 2%lidocaine 10μl via the catheter in anesthetized rats in the other six groups except for C and S groups.Drugs were injected through a microcatheter for 14 consecutive days starting from 3rd day after IT catheterization as follows:DMSO 10μl,curcumin 100μg/10μl and curcumin 500μg/10μl were injected once a day in D,CL and CH groups,respectively;curcumin 500μg/10μl was injected once a day,and D98059 10μg and MK-2206 12μg(in 5μl DMSO)were intraperitoneally injected once a week in P and M groups,respectively.The mechanical paw withdrawal threshold(MWT)and thermal paw withdrawal threshold(TWL)on the operated side were measured on 1 day before IT catheterization,before administration on 3rd day after IT catheterization,and on 14th day after administration.The spinal cord was removed on 1st day after the end of administration for determination of the expression of ERK1/2,phosphorylated ERK1/2(p-ERK1/2),Akt,phosphorylated Akt(p-Akt),c-fos,Bcl-2 and Bax(by Western blot)and expression of ERK1/2 and Akt mRNA(by real-time polymerase chain reaction).Results Compared with group C,the MWT was significantly decreased,the TWL was shortened,the expression of ERK1/2 protein and mRNA,p-ERK1/2,c-fos,Akt protein and mRNA,p-Akt and Bcl-2 was down-regulated,and the expression of Bax was up-regulated in group L(P<0.05).Compared with group L,the MWT was significantly increased,and the TWL was prolonged in CL,CH,P and M groups,the expression of p-ERK1/2,c-fos,p-Akt and Bcl-2 was up-regulated,and the expression of Bax was down-regulated in CL and CH groups,the expression of p-Akt and Bcl-2 was up-regulated,and the expression of Bax was down-regulated in group P,and the the expression of p-ERK1/2 and c-fos was up-regulated in group M(P<0.05).Compared with group CH,the MWT was significantly decreased,and the TWL was shortened in P and M groups,the expression of p-ERK1/2 and c-fos was down-regulated in group P,and the expression of p-Akt and Bcl-2 was down-regulated,and the expression of Bax was up-regulated in group M(P<0.05).Conclusion Curcumin can reduce lidocaine-induced nerve injury,and the mechanism may be partly related to enhancing the activity of Akt and ERK1/2 signaling pathway in rats.