线粒体缺陷对原代培养新生大鼠海马神经元微管相关蛋白表达的影响

Influence of mitochondrial deficiency on expression of microtubule-associated proteins in primary cultured hippocampal neurons of neonatal rats

目的 :观察线粒体呼吸链复合体IV(即细胞色素C氧化酶 )抑制剂叠氮钠 (NaN3)对神经元细胞骨架系统的影响 ,探讨线粒体缺陷在阿尔茨海默病发病中的作用。方法 :将叠氮钠与原代培养的新生大鼠海马神经元共同孵育 ,MTT法测定细胞存活率 ,激光共聚焦显微镜系统观察细胞微管结构及微管相关蛋白表达的变化。结果 :叠氮钠 8- 12 8mmol/L与培养的神经元共孵育 6- 2 4h ,细胞存活率下降 ,呈时间及剂量依赖性 ;NaN316、64mmol/L作用 6h ,使细胞微管结构损伤 ,微管相关蛋白表达下降 ,尤以突起内最为显著。结论 :叠氮钠与培养的神经元共孵育导致神经元损伤 ,其机制与线粒体缺陷致细胞骨架系统异常有关。

AIM: In order to study the relationship between mitochondrial deficiency and Alzheimer's disease(AD), we used sodium azide, a specific inhibitor of cytochrome C oxidase(COX), to develop a cell model of mitochondrial complex IV deficiency and investigated the impairment of microtubules and microtubule-associated proteins. METHODS: Primary cultured hippocampal neurons of hewborn rats were exposed to sodium azide ,then cell viability was measured by MTT method; cell morphology, immunofluorecence-stained cellular microtubules and microtubule-associated proteins were observed by confocal microscopy. RESULTS: Primary cultured hippocampal neurons were exposed to 8-128 mmol/L sodium azide for 3-24 h, MTT absorbance decreased dose-and time-dependently. Exposed to 64 mmol/L sodium azide for 6 h, the processes of cells retracted, synapses disappeared, axons were shortened under contrast microscope. Meanwhile, microtubles were disassembled and became disorderly, the expression of microtubule-associated proteins were also reduced especially in the processes observed by confocal microscopy. CONCLUSIONS: Sodium azide inhibits the assembly and polymerization of tubulin in microtubules which may be reduced by low expression of microtubule-associated proteins in nerve cells. The damage of axons induced by microtubule collapse further blocks the intercellular signal transduction and intracellular material transportation which are important causes in cell death.