Schlemm管在眼内压调节机制及其在原发性开角型青光眼发病机制中作用的研究

Intraocular pressure (IOP) is the main risk factor of glaucoma. Outflow facility reduction is the reason for IOP elevation in most types of glaucoma. There is a precise self-adjustment mechanism for maintaining IOP homeostasis in normal eye. The IOP elevation in primary open angle glaucoma (POAG) patients may be the results of the failure of this self-adjustment mechanism. While there is agreement among most investigators that the bulk of aqueous humour outflow resistance is generated in the immediate vicinity of the inner wall endothelium of Schlemm's canal, the precise location and the mechanism by which this dissipation occurs is still a topic of active debate and research. In this project, cultured porcine Schlemm's canal endothelium, perfused mouse eyes, perfused human anterior segment organ cultures of normal and POAG persons were used to elucidate the mechanism of outflow resistance changes under different IOPs. The extracellular matrix turnover, mediated by the matrix metalloproteinases and cytoskeleton modulation in Schlemm's canal endothelium will be the focus of the research. Through the implementation of this project, we will further clarify the specific mechanisms of IOP self-regulation failure in POAG patients and try to find the possible treatments to restore this dynamic regulation.

眼内压（IOP）升高是青光眼的主要危险因素。各类青光眼患者IOP升高几乎都是由于房水流出受阻所导致。正常人眼中存在着一个精确的IOP自我调节机制，原发性开角型青光眼（POAG）患者IOP升高的机制可能正是由于IOP自我调节机制失灵。Schlemm管内壁及其周围结缔组织是产生房水外流阻力的主要部位，同时也是IOP自我调控的位置所在，但是IOP调控的准确机理尚不清楚。本项目拟使用培养猪眼Schlemm管内皮细胞、离体小鼠眼球青光眼灌注模型、正常人及POAG患者离体眼球灌注模型等作为研究对象，从形态、蛋白表达、功能三个方面研究不同IOP作用下Schlemm管内皮细胞基质金属蛋白酶通路及细胞骨架构型变化改变房水流出阻力的机制，并明确两者之间的相互联系。希望通过本项目的实施，进一步明确POAG患者IOP调控机制失灵的具体机制，尝试寻找恢复POAG患者IOP动态调控机能的治疗药物。

青光眼是世界首位不可逆性致盲性眼病，目前其发病原因尚未研究清楚。现在经过验证唯一有效的治疗方式是降眼压，可通过减少房水生成或者增加房水流出实现。既往研究表明房水流出的主要阻力在小梁网与Schlemm管内壁，本研究通过对用老化状态的Schlemm管内皮细胞模拟青光眼患者Schlemm管内皮细胞，研究其非编码RNA（non-coding RNA,ncRNA）的改变，试图寻找能够减少房水流出阻力进而降低眼压的ncRNA。经过长期研究发现，miR-21是一种能够减少猪Schlemm管内皮细胞单层细胞通透性的ncRNA，同时在动物与离体眼球灌注中研究表明，miR-21能够降低眼内压、通过小梁网途径增加房水流出系数，同时机制的研究表明，此种降眼压机制通路是多通路的，包括PTEN/PI3K/Akt/eNOS/p-eNOS、TIMP3/MMP9 与RhoB/MLC/ROCK1/ROCK2，同时双荧光素报告基因结果显示PTEN/TIMP3/RhoB确实为miR-21的直接靶点。因此miR-21可能是治疗青光眼的潜在新靶点，我们对此进行了专利申请，目前处于实质性审查阶段。我们仅对ncRNA测序结果中的miR-21进行了各层次的功能探究与几个通路验证，还有较多其他信息可以提炼，除此之外对miR-21过表达对转录本影响的测序结果也等待后期完善解读。