鞘内注射右美托咪定对大鼠脊髓缺血再灌注损伤后FGFR3表达及血-脊髓屏障的影响

Intrathecal injection with dexmedetomidine maintained structure and function of blood-spinal cord barrier after ischemia reperfusion through down regulating FGFR3

中文关键词:  脊髓损伤  缺血再灌注  血-脊髓屏障  细胞生长因子受体3  紧密连接相关蛋白  右美托咪定  大鼠

英文关键词:Spinal cord ischemia reperfusion injury  Blood-spinal cord barrier  Fibroblast growth factor receptor 3  Occludin  Dexmedetomidine  Rat

中文摘要:

  【摘要】 目的：观察鞘内注射右美托咪定（dexmedetomidine，Dex）对大鼠脊髓缺血再灌注损伤（spinal cord ischemia reperfusion injury，SCIRI）后细胞生长因子受体3（FGFR3）表达、血-脊髓屏障（blood-spinal cord barrier，BSCB）结构及其相关结构蛋白occludin的影响。方法：120只SD大鼠随机分为4组：假手术组（Sham组）、缺血再灌注损伤组（IR组）、Dex预处理组（Dex组）和Dex+阿替美唑（ATIP）预处理组（Dex+ATIP组），Sham组和IR组分别于造模前3d开始鞘内生理盐水30μl、Dex组鞘内注射10μg DEX（30μl）；Dex+ATIP组鞘内注射右美托咪定10μg+阿替美唑10μg（共30μl），１次／d，连续3d。Sham组仅暴露主动脉弓而不结扎，其他3组开胸后用无创动脉夹夹闭主动脉弓14min后再开放，建立SCIRI模型。分别于造模后12h和48h取L4~L6脊髓，采用干湿法测定脊髓含水量；伊文思蓝（evans blue，EB）染色测定BSCB完整性；Weston blot和RT-PCR测定脊髓组织中FGFR3和occludin含量。结果：造模后12h和48h，与Sham组比较，IR组、Dex组和Dex+ATIP组相应时间点脊髓组织中含水量、EB含量、FGFR3蛋白和基因表达均显著性增加，occludin表达显著性下降（P<0.05）；Dex组与相应时间点与IR组和Dex+ATIP组相比脊髓组织中含水量、EB含量和FGFR3蛋白和基因表达均显著性降低，而occludin表达增加（P<0.05）；Dex+ATIP组与IR组相应时间点比较均无显著性差异。造模后12h和48h，EB染色荧光显微镜下观察Sham组脊髓实质内几乎未见红色荧光，Dex组红色荧光有所增加，而IR组和Dex+ATIP组红色荧光显著增加，48h变化较12h更为显著。结论：鞘内注射Dex可下调大鼠脊髓缺血再灌注损伤后脊髓组织中FGFR3蛋白表达，维持occludin蛋白含量，对血-脊髓屏障起到保护作用。

英文摘要:

  【Abstract】 Objectives: To observe the effects of intrathecal injection with dexmedetomidine(Dex) on expressions of FGFR3, structure of blood-spinal cord barrier(BSCB), and related protein occludin after spinal cord ischemia reperfusion injury(SCIRI) in rat model. Methods: One hundred and twenty rats were randomly divided into four groups: sham group, IR group, Dex group and Dex+ATIP group. Intrathecal injection of 30μl normal saline was performed in sham group and IR group, 10μg dexmedetomidine(30μl) in Dex group, and 10μg dexmedetomidine and 10μg ATIP(total in 30μl) in Dex+ATIP group. Intrathecal injection was done once a day and continuously for 3 days. Aortic arch was only exposed but not occluded in sham group. SCIRI model in the other three groups were established by aortic arch occlusion for 14min. At 12h and 48h after model-making, L4-L6 segments of spinal cord were extracted. Spinal water content was determined by wet and dry method. Evan′s Blue(EB) extravasation was used to assess the structure of BSCB. Protein and mRNA expression of FGFR3 and occludin were assessed by Weston blot and PCR. Results: Compared with sham group, rats in IR group, Dex group and Dex+ATIP group had significantly higher spinal water content, EB extravasation, protein and mRNA levels of FGFR3, but lower protein and mRNA level of occludin at both 12h and 48h after model-making(P<0.05). Compared with IR group and Dex+ATIP group at the above time points, rats in Dex group had lower spinal water content, EB extravasation, protein and mRNA level of FGFR3, but higher level of occludin(P<0.05). There were no significant differences in the above indexes between IR group and Dex+ATIP group. At 12 and 48h after model-making, almost no red fluorescent stain was visualized in spinal cord parenchyma of sham group under microscopy, a little more fluorescent stain was observed in Dex group, but red fluorescent stain was observed markedly increase in IR group and Dex+ATIP group. The changes at 48h were more obviously than those at 12h. Conclusions: Intrathecal injection with Dex can maintain structure of BSCB and preserve expression of occludin by inhibiting spinal FGFR3 expression.