线粒体钙单向转运体在颅脑海水浸泡伤中的作用机制研究

Traumatic brain injury ranks first in trauma in the marine settings, which is easy to be influenced by sea water such as immersion and makes it difficult to be treated. Mitochondria play multiple functions by taking Ca2+ through the mitochondrial Ca2+ uniporter (MCU). In brain injury, mitochondrial Ca2+ overload transported through MCU plays the key role in mitochondrial and neuronal injury,while the use of MCU inhibitors can significantly reduce tissue damage. Recently, the structure of MCU has been clarified by gene overexpression or RNAi, and the function of MCU can be directly intervened by RNAi and other related methods. Our previous work has proved that sea water can aggreviate the degree of traumatic brain injury. In this study, controlled cortical impact model and in vitro mechanic injury model will be treated by sea water. The methods of pathology, molecular biology,immunofluorescence technique and electron microscopy will be used to investigate the changes of brain tissue and MCU expression. RNAi and overexpression of MCU will also be used to confirm the role of MCU in brain injury.The objective of the study is to clarify the role of MCU in sea water-related brain injury and to provide new target for the treatment of acute brain injury.

颅脑外伤是最常见的海上创伤类型，容易受到海水浸泡影响，救治难度大。线粒体通过线粒体钙单向转运体（MCU）摄入Ca2+是线粒体发挥生理作用的基础，也是脑损伤时引起线粒体Ca2+超载和一系列病理改变，造成神经损伤的关键因素，研究表明使用MCU阻断剂能减轻组织损伤。近年来，MCU的确切结构已经通过基因过表达、RNAi等方法得到证实，因而能通过基因方法对MCU进行直接干预，研究MCU在神经疾病中的作用。我们的前期研究发现海水浸泡能加重原有的脑组织损伤，本课题在前期研究的基础上，以大鼠脑组织打击模型和神经细胞机械损伤模型为基础，并使用海水进行处理，采用病理学、分子生物学、免疫荧光技术、电镜等方法检测海水浸泡对神经系统损伤的影响以及MCU的变化情况，并通过RNAi或过表达等方式干预MCU的功能，验证MCU在颅脑海水浸泡伤中的作用。本课题有望为包括颅脑海水浸泡伤在内的急性脑组织损伤治疗提供潜在的治疗靶点。

本课题的主要研究内容是以大鼠脑组织打击模型和神经细胞机械损伤模型为基础，并使用海水进行处理，采用病理学、分子生物学、免疫荧光技术、电镜等方法检测海水浸泡对神经系统损伤的影响以及线粒体钙单向转运体（MCU）的变化情况，并通过RNAi或过表达等方式干预MCU的功能，验证MCU在颅脑海水浸泡伤中的作用。通过研究，我们建立了小鼠颅脑损伤合并海水浸泡体外模型，发现颅脑损伤合并海水浸泡伤使得神经元线粒体内钙离子浓度升高，加重神经元线粒体功能障碍，促进神经元凋亡，从而显著加重神经元的损伤。而采用病毒转染技术沉默MCU可以降低神经元线粒体内钙离子浓度，有效减轻神经元损伤、凋亡并减轻线粒体功能障碍，而过表达MCU并不加重神经元凋亡。该研究证明了MCU在是神经元损伤的重要因素，通过降低MCU的活性，能够降低线粒体内的钙离子浓度，减轻线粒体的损伤，从而发挥神经元保护作用。