激活Akt/mTOR/p70S6K信号通路对大鼠脊髓损伤后神经再生的影响  

The effects of activated Akt/m TOR/p70S6K signaling pathway on the neural regeneration after spinal cord injury in rats

作　　者：胡凌云[1,2] 张建英[1,3] 林涛[1,2] 苟林[1,2] 林宏[1,2] 李伟 刘康[4] 孙振刚[5] 

机构地区：[1]川北医学院第二临床医学院 [2]四川省南充市中心医院骨科,637000 [3]四川省南充市中心医院影像中心,637000 [4]川北医学院组织工程与干细胞研究所,四川省南充市637000 [5]山东省青岛市经济开发区第一人民医院骨科,266555

出　　处：《中国脊柱脊髓杂志》2015年第1期67-75,共9页Chinese Journal of Spine and Spinal Cord

基　　金：国家自然科学基金资助项目(编号:81100929)

摘　　要：目的：探讨激活蛋白激酶B（Akt）/哺乳动物雷帕霉素靶蛋白（m TOR）/p70核糖体S6蛋白激酶（p70S6K）信号通路对大鼠脊髓损伤（spinal cord injury,SCI）后神经再生及神经功能恢复的影响,为促进SCI修复提供分子学机制依据。方法：72只雌性SD大鼠建立轻型SCI模型后随机均分为激活组（Act组,SCI＋ATP）、对照组（Con组,SCI＋生理盐水）、阻断组（Int组,SCI＋ATP＋雷帕霉素）;24只大鼠仅打开椎板、不损伤脊髓,为假手术组（Sham组）。分别于术后1d、3d、7d、14d采用BBB运动功能评分评价各SCI组大鼠经不同治疗后的神经功能,并采用Western blot检测各组在术后各时间点脊髓组织中Akt、p-Akt、m TOR、p-m TOR、p70S6K、p-p70S6K、Nestin、Neu N蛋白表达情况,免疫组化检测各组在术后各时间点的Nestin和Neu N表达情况。结果 ：各SCI组术后1d BBB评分为3～5分,之后逐渐增加,术后1d和3d各组间BBB评分无显著性差异（P〉0.05）,Act组在SCI后7d和14d时的BBB评分明显高于Con与Int组（P〈0.05）。各SCI组在术后各时间点脊髓组织中Akt、m TOR及p70S6K磷酸化水平均明显高于Sham组（P〈0.05）,Act组的磷酸化水平在术后各时间点均明显高于Con组及Int组（P〈0.05）,术后7d时磷酸化水平增高最为显著（P〈0.01）。各SCI组大鼠在术后各时间点的Nestin表达水平均高于Sham组（P〈0.05）,Act组的表达水平较Con组、Int组显著性增高（P〈0.05）、Nestin阳性细胞数显著性多于Con组与Int组（P〈0.05）。各SCI组在术后各时间点的Neu N表达均显著性低于Sham组（P〈0.01）,各SCI组Neu N的表达在术后1d、3d无显著性差异（P〉0.05）;Act组在术后7d和14d时的Neu N表达水平明显高于Con组及Int组（P〈0.05）,Neu N阳性细胞数明显多于Con组与Int组（P〈0.05）。结论：激活Akt/m TOR/p70S6K信号通路可显著增加SCI后Nestin及Neu N的表达,促进SCI后神经恢复和功能改善,此信号�Objectives： To examine the impacts of the protein kinase B（Akt）/mammalian target of rapamycin（m TOR）/p70 ribosomal S6 protein kinase（p70S6K） signaling transduction pathway on neural regeneration and functional recovery after spinal cord injury（SCI） in adult rats, and to provide the molecular mechanism for promoting the SCI repair. Methods： A total of 72 female Sprague-Dawley rats of minimal injury model was randomly divided into the following groups： activation group（Act group, SCI plus ATP）, control group（Con group, SCI plus saline） and interruption group（Int group, SCI plus ATP and rapamycin）. The sham-operated group（Sham group） including 24 rats undergoing laminectomy without SCI. The BBB locomotor rating scale was used to evaluate the animal′s locomotor performance after different treatments were administered at 1, 3,7, and 14 days following SCI. The changes of Akt, p-Akt, m TOR, p-m TOR, p70S6 K, p-p70S6 K, Nestin and Neu N expressions in spinal cord tissues of all groups were detected by using Western blot analysis at all experimental time points after different disposals were administered following surgery, and the immunostaining was further performed for detecting the Nestin and Neu N in all groups after surgery. Results： Locomotor function assessment showed the BBB scores were 3-5 in the animals with SCI at 1d after injury, which gradually exhibited partial recovery of locomotor function after 1d following injury. No significant differences in BBB scores were observed among the three SCI groups at 1d and 3d after injury（P〈0.05）. At 7d and 14 d after injury, the rats in the Act group exhibited significantly higher BBB score compared with the rats in the Con and Int group（P〈0.05）. Western blot showed prominently elevated phosphorylation level of Akt, m TOR and p70S6 K in spinal cord tissues of all SCI groups at all experimental time points after surgery compared with the sham-operated group（P〈0.05）. The phosphorylation level of this signaling path

关 键 词：脊髓损伤 MTOR 雷帕霉素 蛋白激酶信号级联 神经再生 大鼠 

分 类 号：R683.2[医药卫生—骨科学] Q189[医药卫生—外科学]