耳蜗血管纹固有巨噬细胞在血迷路屏障发育中的作用

Macrophages, with multifunction, are essential componential cells in most mammalian tissues. They play great functions in host defect, the clearance of apoptotic cells, tissue development, homeostasis and tissue repair. Tissue –resident macrophages have many tissue-specific functional characters. There are resident macrophages in stria vascularis. But its roles in the development and function of BLB remain still unknown. This project will use a diphtheria toxin receptor transgenic mice model, postborn six days, with the intraperitoneal injection of diphtheria toxin, to delete macrophage in the stria vascularis of the cochlea. We will use these macrophage-deficient mouse models to study the relationship between macrophage-deficient and the blood labyrinth barrier development: using fluorescent tracers /transmission electron microscopy to detect the permeability of the stria vascularis blood - labyrinth barrier, using brainstem auditory evoked potentials and endocochlear potential to test hearing, using immunohistochemical method, western blotting，PCR and to test endothelial cell protein expression,using gene chips to study the changes of gene expression within the stria vascularis. These studies together will explain the impacts of macrophages on the cochlea stria vascaularis blood–labyrinth-barrier development from function, morphology, protein, gene and cell levels, and these will also provide a theoretical basis for therapy of hearing loss.

巨噬细胞是哺乳动物大多数组织具有多种功能的重要组成细胞，在宿主免疫、调亡细胞清理、组织发育、稳态维持和组织修复起重要作用。组织固有巨噬细胞具有组织特异性功能，耳蜗血管纹存在固有巨噬细胞，是血迷路屏障的重要组成成分，在耳蜗的发育和功能起何作用尚不清楚。本课题将采用人白喉毒素受体转基因小鼠模型，出生后六天开始进行白喉毒素腹腔注射，部分去除耳蜗血管纹巨噬细胞，运用脑干诱发电位、共聚焦显微镜、透射电镜、免疫组化、流式细胞、多聚酶链反应、免疫印迹、基因芯片等研究方法，重点研究耳蜗血管纹巨噬细胞去除之后，成年小鼠听觉功能的改变以及耳蜗血管纹毛细血管通透性、紧密连接蛋白、转运相关蛋白的影响。实现从功能、结构、蛋白质、基因等多角度阐明血管纹固有巨噬细胞在耳蜗血管纹血迷路屏障发育中具有重要作用的研究目标，对理解听觉的产生和维持、耳聋的发生机理以及寻找针对巨噬细胞的耳聋治疗的潜在靶点具有重要的科学意义。