摘要
目的探讨右美托咪定(Dex)对兔脊髓缺血再灌注损伤(SCIRI)的保护作用及潜在分子机制。方法采用成年新西兰大耳白兔复制SCIRI模型。实验一:42只兔随机分为7组,分别于灌注前(0 h)及再灌注后3 h、6 h、12 h、24 h、36 h及48 h 7个不同时间点,用Western blotting法检测脊髓组织磷酸化的Janus激酶2(p-JAK2)、磷酸化的信号转导与转录激活因子3(p-STAT3)的表达。实验二:36只兔随机分为对照组(Sham组)、缺血再灌注组(I/R组)及Dex干预组(Dex+I/R组)。Sham组分离腹主动脉后,不做缺血处理。I/R组和Dex+I/R组,分离腹主动脉并夹闭30 min,以诱导脊髓组织缺血。脊髓缺血前30 min,Dex+I/R组静脉给予Dex[10μg/(kg·h),直至再灌注后1 h。再灌注后48 h对兔后肢运动功能进行Tarlov评分,苏木精-伊红(HE)染色观察脊髓组织病理学改变,原位末端转移酶标记(TUNEL)检测神经细胞凋亡情况,伊文思蓝检测血-脑屏障的渗透性,Western blotting法检测脊髓组织p-JAK2、p-STAT3、活化型半胱天冬酶-3(Cleaved caspase-3)、肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)的表达。结果实验一:与灌注前(0 h)比较,再灌注后6 h、12 h、24 h及36 h脊髓组织p-JAK2、p-STAT3的表达增加(均P<0.05),并于24 h到达峰值。实验二:再灌注后48 h,Dex+I/R组的Tarlov评分增加(P<0.05),脊髓组织损伤减轻;Dex处理能够降低脊髓神经细胞凋亡率(P<0.05),并减少脊髓组织中伊文思蓝的渗透量(P<0.05);Dex上调p-JAK2、p-STAT3的表达(P<0.05),并下调Cleaved caspase-3、TNF-α和IL-6的表达(P<0.05)。结论再灌注阶段,存在JAK2/STAT3保护性通路的激活,但这种激活作用并未维持;Dex可通过激活JAK2/STAT3信号通路、抑制凋亡蛋白(Cleaved Caspase-3)和炎症因子(TNF-α,IL-6)表达,从而减少神经细胞凋亡并维持血-脑屏障的完整性,减轻SCIRI。
Objective To investigate the role of a combination of per-and post-conditioning of dexmedetomidine(Dex)in rabbits with spinal cord ischemia-reperfusion injury(SCIRI).Methods Adult New Zealand white rabbits were used to replicate the SCIRI model.Experiment 1:Animals(42)were randomly divided into seven groups to evaluate the time-course expression of p-JAK2 and p-STAT3 after reperfusion.Experiment 2:Animals(36)were randomly divided into three groups:Sham,I/R and Dex+I/R.For the I/R group and I/R+DEX group,the abdominal aorta of the rabbits was clamped for 30 min to establish the model of SCIRI,while the rabbits in the Sham group only undergoing arterial dissociation.Dex(10μg/(kg·h)was administered intravenously 30 min before ischemia until 1 h after reperfusion.Hind limb motor function was assessed using the modified Tarlov scale score at 48 h after reperfusion.Histopathological changes and neuronal apoptosis in the ventral grey matter were assessed by hematoxylin-eosin(HE)staining and TdT-mediated dUTP nick end labeling(TUNEL).The permeability of the blood-spinal cord barrier(BSCB)was examined via Evans blue(EB)extravasation.The protein expressions of p-JAK2,p-STAT3,Cleaved Caspase-3,TNF-α,and IL-6 were detected by Western blotting.Results Experiment 1:Compared with the 0 h group,the expression of p-JAK2 and p-STAT3 in the spinal cord tissue were increased at 6 h,12 h,24 h,and 36 h after reperfusion(all P<0.05),and reached a peak at 24 h.Experiment 2:At 48 h after reperfusion,Dex treatment significantly increased Tarlov score(P<0.05)and alleviated the histological damage of spinal cord in rabbits;Dex treatment markedly reduced neuronal apoptosis(P<0.05)and decreased EB content in spinal cord tissue(P<0.05);Dex significantly up-regulated the expression of p-JAK2 and p-STAT3(both P<0.05),and down-regulated the expression of Cleaved Caspase-3,TNF-α,and IL-6(all P<0.05).Conclusions In the reperfusion phase,JAK2/STAT3 protective pathway is activated,but it is not maintained.Combination of per-and postconditioning o
作者
樊晓娜
刘娇
池卉
袁芬
胡霁
Xiao-na Fan;Jiao Liu;Hui Chi;Fen Yuan;Ji Hu(Department of Anesthesiology,Liyuan Hospital of Tongji Medical College,Huazhong University of Science and Technology,Wuhan,Hubei 430077,China)
出处
《中国现代医学杂志》
CAS
2020年第19期7-14,共8页
China Journal of Modern Medicine
基金
中央高校基本科研业务费专项资金资助(No:2016YXZD024,2017KFYXJJ085,2018KFYYXJJ118)。
