鞘内注射右美托咪定增加神经元自噬改善大鼠脊髓缺血再灌注损伤后神经运动功能

发布时间：2019-04-16 19:25

【摘要】：目的观察注射右美托咪定(Dexmedetomidine,DEX)预处理对在体大鼠脊髓缺血再灌注损伤(Spinal cord ischemia reperfusion injury,SCIRI)后神经元自噬和下肢运动功能的影响。方法 SD大鼠随机分为4组(每组30只):假手术组(Sham组)、缺血再灌注损伤组(IR组,鞘内注射30μL生理盐水)、Dex组(缺血前3 d鞘内注射右美托咪定10μg/30μL)、Dex+ATIP组(缺血前3 d鞘内注射10μg右美托咪定+10μg阿替美唑共30μL)。Sham组仅暴露主动脉弓而不结扎,其他各组开胸后无创动脉夹夹闭主动脉弓14 min后再开放,建立SCIRI模型。各组手术前均于L5-6鞘内置管并连续注射3 d。损伤后48 h内每12小时取5只大鼠,采用Tarlov法评价大鼠下肢运动功能;HE染色观察和计数损伤后48 h脊髓前角神经元形态和数量;Western blot和RT-PCR法测定损伤后48 h大鼠脊髓组织中自噬相关蛋白Beclin1、LC3蛋白及mRNA含量。结果与Sham组比较,术后各观察点IR组下肢运动功能明显受损,Tarlov评分下降,脊髓组织中Beclin1、LC3蛋白及mRNA的表达均明显降低(P0.05);损伤前3 d鞘内注射10μg DEX(Dex组)可改善缺血再灌注损伤后下肢运动功能,提高Tarlov评分,改善脊髓Beclin1、LC3 mRNA蛋白的表达(P0.05),而Dex+ATIP组与IR组比较差异无统计学意义(P0.05)。损伤后48 h,HE染色显示,Sham组脊髓前角神经元轮廓清晰,结构完整,无出血、水肿等异常表现;IR组、Dex+ATIP组细胞质中的尼氏体消失,神经元胞核出现固缩或溶解,广泛空泡形成;而Dex组神经元形态明显规整,且正常神经元数量增多。结论鞘内注射右美托咪定预处理通过上调Beclin1、LC3蛋白和基因表达,增加神经元自噬,改善大鼠缺血再灌注后下肢运动功能。
[Abstract]:Aim to observe the effects of pretreatment with right metametidine (Dexmedetomidine,DEX) on neuronal autophagy and lower limb motor function after spinal cord ischemia-reperfusion injury (Spinal cord ischemia reperfusion injury,SCIRI) in rats in vivo. Methods SD rats were randomly divided into 4 groups (30 rats in each group): sham operation group (Sham group), ischemia reperfusion injury group (IR group, intrathecal injection of 30 渭 L saline), Dex (intrathecal injection of right metomide 10 渭 g / 30 渭 L) 3 days before ischemia). In Dex ATIP group (intrathecal injection of 10 渭 g right metametrimidine 10 渭 g atimeimazole) 3 days before ischemia, only aortic arch was exposed without ligation in 30 渭 L). Sham group, and non-invasive aortic arch was closed for 14 min after thoracotomy in other groups. The SCIRI model was established by intrathecal injection of 10 渭 g right metometrimidine 10 渭 g atimezole. All the patients in each group were placed in the sheath of L _ 5 ~ 6 before operation and injected continuously for 3 d. Within 48 hours after injury, 5 rats were taken out every 12 hours to evaluate the motor function of the lower extremities by Tarlov method, and the morphology and number of neurons in the anterior horn of spinal cord were observed and counted by HE staining at 48 hours after injury. The contents of Beclin1,LC3 protein and mRNA in spinal cord tissue of 48 h after injury were determined by Western blot and RT-PCR. Results compared with Sham group, the motor function of lower extremities and the expression of Beclin1,LC3 protein and mRNA in spinal cord were significantly decreased in IR group after operation (P0.05). The scores of Tarlov were decreased, and the expression of Beclin1,LC3 protein and mRNA in spinal cord were significantly decreased (P0.05). Intrathecal injection of 10 渭 g DEX (Dex 3 days before injury could improve lower limb motor function, increase Tarlov score and improve the expression of Beclin1,LC3 mRNA protein in spinal cord after ischemia-reperfusion injury (P0.05). There was no significant difference between Dex ATIP group and IR group (P0.05). 48 hours after injury, HE staining showed that neurons in the anterior horn of the spinal cord in the Sham group were clear in outline, complete in structure, without hemorrhage and edema. In IR group, the Nissl body disappeared in the cytoplasm of, Dex ATIP group, the nucleus of neurons became pyknotic or dissolved, and extensive vacuoles were formed, while the morphology of neurons in Dex group was obviously regular, and the number of normal neurons was increased. Conclusion Intrathecal injection of right metomidine can improve the motor function of lower limbs after ischemia-reperfusion by up-regulating the expression of Beclin1,LC3 protein and gene and increasing the autophagy of neurons.
【作者单位】：中国医科大学附属第一医院麻醉科;
【基金】：辽宁省科学技术计划项目(2012408002) 国家自然科学基金(81271370)
【分类号】：R614

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