内质网应激在抑郁障碍脑供血不足中的发病机制研究

While there is evidence that major depressive disorder (MDD) often associated with cognitive dysfunction, this mechanism is not clear and it is difficult to cure，some studies show that major depressive disorder is comorbided with cerebral insufficiency which may contribute to this. It have become a new focus of study on the pathogenesis and treatment of target in major depressive disorder with cerebral insufficiency. In the preliminary studies, the results suggest there is an increase in pro-apoptotic pathways in the chronic mild stress (CMS) model of major depressive mood in rodents, neuronal apoptosis occurs in the cerebral cortex and subcortical central. Further study was found in clinical study that major depressive disorder is characterized by a wide range of regional cerebral blood flow impairments in the cerebral cortex and subcortical central and prominent changes in gray matter blood flow. We presume that the endoplasmic reticulum stress signaling pathway may be activited, which results in cerebral insufficiency. In order to prove this hypothesis, this study will utilize transmission electron microscope, western-blotting, real-time PCR techniques and so on, to assess the expression of endoplasmic reticulum stress parameters in cortex、hippocampus and cerebral vascular endothelial cells by both CMS model and cell research, furthermore to analyze and compare the effects of Escitalopram Oxalate、N-Acetylcysteine、β-blockers (Metoprolol) on endoplasmic reticulum stress-related signal transduction pathway phospho-extracellular signal-regulated kinase (PERK) gene expression, in order to elucidate the pathogenesis of endoplasmic reticulum stress in the of impaired regional cerebral blood flow on depressive disorder. This has the capacity to provide a theoretical basis for novel treatment options for the clinical treatment of dysregulated cerebral blood flow associated with major depressive disorder.

抑郁障碍患者存在认知功能障碍，其机制不清，治疗不佳。有观点认为抑郁障碍共病脑供血不足，可能与此相关。因此探索抑郁障碍后脑供血不足的发病机制及治疗靶点成为焦点。课题组前期研究发现，抑郁模型大鼠大脑皮层及海马神经元凋亡通路被激活，神经元发生凋亡。进一步的临床研究发现，抑郁障碍患者呈现广泛的大脑皮层及皮层下低血流灌注特征，经分析认为抑郁障碍后内质网应激信号通路可能被激活，从而导致了脑供血不足的发生。本课题为了验证这个观点，采用透射电镜、免疫印迹和实时荧光定量PCR等方法，从动物实验、细胞实验不同的角度探索内质网应激相关分子在大脑皮层、海马、大脑血管内皮细胞的表达作用，分析比较草酸艾司西酞普兰、N-乙酰半胱氨酸、β-受体阻滞剂对内质网应激PERK凋亡通路相关基因表达的调控作用，阐明内质网应激在抑郁障碍后脑供血不足的发病机制，积极寻找治疗靶点，为临床治疗奠定理论基础和提供新的手段和策略。

为了探索内质网应激对抑郁障碍发病的影响及相关机制，明确艾司西酞普兰通过调控内质网应激发挥抗抑郁作用的机制。本项目从抑郁动物模型实验、细胞实验两个方面进行深入研究，采用透射电镜、免疫印迹、实时荧光定量PCR等方法，分析了内质网应激相关分子在大脑皮层、海马、大脑血管内皮细胞中的表达，比较分析草酸艾司西酞普兰、N-乙酰半胱氨酸、β-受体阻滞剂对内质网应激通路相关基因表达的调控作用，以及对衣霉素诱导的大脑血管内皮细胞内质网应激凋亡模型的影响。动物实验结果表明，抑郁障碍发生时内质网应激及相关细胞凋亡通路被激活，提示内质网应激可能是抑郁障碍发病机制之一。同时，艾司西酞普兰、N-乙酰半胱氨酸、美托洛尔可以通过下调内质网应激相关蛋白及基因，减少海马细胞凋亡，改善抑郁动物模型的行为。在细胞水平，发现上述现象可能与IRE1/XBP1、PERK-ATF4-CHOP、IRE1-JNK- CHOP信号通路相关，进一步研究发现，内质网应激发生时通过激活CaMKII通路及启动eNOS解耦联，导致血脑屏障通透性增高，而抗抑郁药物西酞普兰可以逆转上述现象，这可能是其抗抑郁治疗的新机制之一。