低氧预适应对缺血再灌注脑损伤小鼠学习记忆的影响及机制研究

发布时间：2018-03-29 11:14

本文选题：低氧预适应　切入点：缺血再灌注　出处：《泰山医学院》2014年硕士论文

【摘要】：研究目的： 1．研究低氧预适应对缺血再灌注脑损伤小鼠学习记忆的影响。 2．研究低氧预适应对缺血再灌注脑损伤后海马CA1区神经细胞凋亡的影响。 3．研究低氧预适应对缺血再灌注脑损伤后海马CA1区MAP-2表达的影响。研究方法： 1．取体重为18-22g健康成年昆明小鼠，雄性，30只，将小鼠随机分为正常组（Ngroup）、假手术组（C group）、缺血再灌注组（O group）、低氧预适应组（HPC group）和低氧预适应+缺血再灌注组（HPC+O group）。每组小鼠6只。应用Morris水迷宫实验进行行为学检测，记录定位航行实验的平均潜伏期及空间探索实验的平台穿越次数和平台象限游泳时间。 2．实验选用体重为18-22g健康昆明小鼠，雄性，132只，将实验小鼠随机分为正常对照组（N group）、低氧预适应组（HPC group）、假手术组（C group）、缺血再灌注组（O group）和HPC+O组，其中O组和HPC+O组又分为缺血再灌注1天、3天、7天和14天四个亚组，每组12只。HPC+O组于缺血再灌注前24h给予低氧预处理。O组和HPC+O组在相应时间点处死取脑，C组在手术后24h处死取脑、HPC组在低氧预适应后24h处死取脑，N组立即处死取脑。通过免疫荧光染色法对脑组织切片进行检测，于荧光显微镜下观察海马中CA1神经细胞凋亡情况，并观察MAP-2表达的分布，以及在海马CA1区表达的动态变化。所有的实验数据均以均数±标准差（x s）表示，统计学检验采用SPSS13.0软件单因素方差分析（One WayANOVA），P0.05。研究结果： 1．本实验成功复制低氧预适应模型和全脑缺血再灌注模型。 2．水迷宫结果显示：与N组相比，HPC组小鼠学习记忆能力明显增加，差异有统计学意义，P0.05，而O组小鼠学习记忆能力明显降低，P0.05；与O相比，HPC+O组小鼠学习记忆能力明显改善，P 0.01。 3．荧光显微镜免疫荧光染色法检测神经细胞凋亡情况：缺血再灌注模型成功后，，凋亡神经细胞在3d时表达最多；HPC+O3d组与N组、C组及HPC组相比，差异有统计学意义，P0.05。HPC+O1d组、HPC+O7d组、HPC+O14d组与N组、C组及HPC组相比，差异无统计学意义，P0.05。 4．荧光显微镜免疫荧光染色法测定MAP-2蛋白表达：缺血再灌注模型成功后，MAP-2阳性表达率增加在，7d时表达最多；与O组相比，HPC+O组MAP-2阳性表达明显降低，统计学有显著性差异，P0.05；N、C组及HPC组，MAP-2基本无表达。结论： 1．低氧预适应可以增加正常小鼠的学习记忆能力。 2．缺血再灌注脑损伤小鼠能出现不同程度的认知功能障碍。 3．低氧预适应能改善缺血再灌注脑损伤小鼠的学习记忆能力。 4．低氧预适应能减少缺血性再灌注损伤小鼠的凋亡，起到神经保护作用。 5．低氧预适应能降低MAP-2阳性表达率，增加海马区突触可塑性，从而提高学习记忆的能力。这对深入了解低氧预适应对缺血再灌注性脑损伤学习记忆保护作用有重要意义，同时可为临床上防治脑缺血/低氧后认知功能损伤提供新策略和科学的实验依据。
[Abstract]:Purpose of study :

1 . To study the effects of hypoxic preconditioning on learning and memory of mice with cerebral ischemia - reperfusion injury .

2 . To study the effect of hypoxic preconditioning on neuronal apoptosis in CA1 region of hippocampus after ischemia - reperfusion .

3 . To study the effect of hypoxic preconditioning on MAP - 2 expression in CA1 region of hippocampus after ischemia - reperfusion .

Study method :

1 . Adult Kunming mice weighing 18 - 22 g were randomly divided into normal group ( Ngroup ) , sham operation group ( C group ) , ischemia / reperfusion group ( O group ) , hypoxic preconditioning group ( HPC group ) and hypoxic preconditioning + ischemia reperfusion group ( HPC + O group ) . 6 . The Morris water maze test was used to carry out the behavioral test , and the average latency and the space exploration experiment were recorded for the average latency and the platform quadrant swimming time .

2 . Experimental mice were randomly divided into three groups : normal control group ( N group ) , hypoxic preconditioning group ( HPC group ) , sham operation group ( C group ) , ischemia / reperfusion group ( O group ) and HPC + O group .

Results of the study :

1 . The hypoxic preconditioning model and global cerebral ischemia / reperfusion model were successfully replicated in the experiment .

2 . The water maze showed that the learning and memory ability of mice in HPC group was significantly higher than that in group N , P 0.05 , while the learning and memory ability of group O mice decreased significantly , P0.05 ;
Compared with O , the learning and memory ability of mice in HPC + O group was significantly improved , P 0.01 .

3 . Fluorescent microscopy immunofluorescence staining method was used to detect the apoptosis of nerve cells : after the ischemia / reperfusion model , the apoptotic nerve cells were expressed most at 3d ;
Compared with group N , group C and HPC group , HPC + O3d group had statistical significance , P0.05 . HPC + O1d group , HPC + O7d group , HPC + O14d group had no significant difference compared with group N , group C and HPC group , P0.05 .

4 . The expression of MAP - 2 protein was determined by fluorescence microscope immunofluorescence staining . After successful ischemia / reperfusion model , the expression of MAP - 2 was increased , and the expression of MAP - 2 was highest at 7d .
Compared with the O group , the positive expression of MAP - 2 in HPC + O group was significantly lower than that in O group ( P0.05 ) .
MAP - 2 was not expressed in group N , C and HPC .

Conclusion :

1 . hypoxic preconditioning can increase the learning and memory ability of normal mice .

2 . Different degrees of cognitive impairment can be found in the brain injury mice after ischemia / reperfusion .

3 . hypoxic preconditioning can improve the learning and memory ability of mice with cerebral ischemia - reperfusion injury .

4 . hypoxic preconditioning can reduce the apoptosis of ischemic reperfusion injury mice and play a role of neuroprotection .

5 . hypoxic preconditioning can decrease MAP - 2 positive expression rate , increase synaptic plasticity in hippocampus region , and improve learning and memory ability .

It is of great significance to understand the effect of hypoxic preconditioning on the learning and memory protection of ischemia - reperfusion brain injury , and it can provide new strategy and scientific experimental basis for the prevention and treatment of cognitive impairment after cerebral ischemia / hypoxia .

【学位授予单位】：泰山医学院
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R743

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