黄芪对青光眼视神经病变中视网膜胶质细胞活化因子转录表达的影响

Current hypotensive treatment options are not sufficient to block neurodegenerative injury in patients with glaucoma.Progressive degeneration of retinal ganglion cells (RGCs) andtheir axons is the primary cause of glaucomatous visual loss.We focused our efforts on better understanding of the precise pathogenic mechanisms of glaucomatous optic neuropathy(GON).Growing evidence now supports that RGC-glia interactions are critically important for different aspects of GON. Despite their relative protection from glaucomatous injury, glial cells prominently respond to glaucomatous stress when exhibit an activated phenotype.Glia-targeting treatment appears to be a promising strategy that could be directed at regulating the initial glial response, reversing the neurodestructive consequences of glial activation, or regaining glial neurosupportive functions. Radix Astragali, which can benefiting qi for diuresis，has been demonstrated by clinical and experimental research as an neuroprotective herb. We also found Radix Astragali make effect by inhibit the neurotoxic response from excessive glutamate, and this process is very similar with what Müller acts because only this type of cell in retina can generate glutamine synthetase to cleanup glutamate.Based on these reasons, we hypothesize that the effect of Radix Astragali may derived from regulating glia regain neurosupport functions. This research will focus on the effectors origin from glia response to GON and what Radix Astragali can do during the intervention. We also expect more details about the neuroprotect effect of Radix Astragali in molecular level.

青光眼目前治疗以降眼压为主，但已有证据表明即使眼压控制很好，神经元仍遭受继发的、持续的损伤，即青光眼性视神经病变（GON），防治GON需从其发病机制- - RGCs凋亡着手，胶质细胞活化同时具有视神经损伤和视神经保护两种作用，既是RGCs凋亡的启动因素，又是决定受损RGCs能否得到修复的关键环节，针对胶质细胞的靶向治疗有望通过引导将胶质细胞活化转向视神经保护方向而发挥GON保护作用。黄芪作为补气行水中药的代表，在既往临床和基础研究中证实具有RGCs保护作用，且其抗谷氨酸毒性的作用与唯一具有谷氨酸清除作用的胶质细胞功能类似，结合其补气行水的功能和现代药理学作用机制，我们推测黄芪的RGCs保护作用与调节视网膜胶质细胞有关，我们将通过分析GON病变中胶质细胞相关信号因子的转录表达及黄芪的干预效应，对这一假说进行验证，并进一步明确黄芪视神经保护作用的分子机制。

背景：黄芪在既往临床和基础研究中证实具有青光眼视神经损伤保护作用，且其抗谷氨酸毒性的作用与唯一具有谷氨酸清除作用的胶质细胞功能类似，结合其补气行水的功能和现代药理学作用机制，我们推测黄芪的RGCs保护作用与调节视网膜胶质细胞有关。本项目采用免疫组织化学、RT-PCR等方法分析了GON病变中胶质细胞相关信号因子的转录表达及黄芪的干预效应；同时，由于视神经横断伤后视网膜RGCs仍具有一定的生长功能，为研究黄芪对视网膜整体及其微环境的影响，并尽量排除全身因素对局部组织真实反应的干扰，本研究还采用视网膜器官培养的方法黄芪对视网膜器官的药理机制进行了初步研究。.目的：研究黄芪对青光眼视神经病变中视网膜胶质细胞活化因子转录表达的影响。.方法：房注入微珠法建立青光眼大鼠试验动物模型，检测模型鼠视网膜神经胶质细胞活性对视网膜神经节细胞凋亡的影响，并采用免疫组化、RT-PCR、视网膜组织培养等方法研究黄芪对视网膜胶质细胞活化因子表达及转录水平的影响。.结果：前房注入20μL含有浓度为2×105个/μL乳胶微球的无菌溶液可造成大鼠青光眼眼压持续升高，HE染色证实视RGCs排列明显紊乱、核固缩、神经纤维层变薄，TUNEL检测证实RGCs大量凋亡，均符合青光眼视神经损伤的病理改变；GFAP染色进一步证明青光眼模型鼠中胶质细胞大量活化；免疫组化检测和RT-PCR检测结果初步证实黄芪干预青光眼模型鼠可下调视网膜胶质细胞中TNF-α、FADD的表达，同时上调抗凋亡蛋白HSP70的表达；视网膜器官培养结果初步证实模型鼠活性胶质细胞增多，黄芪干预有望降低视网膜胶质细胞活化，其具体机制尚待进一步研究。.结论：前房灌注微珠可较好的模拟青光眼发表的病理过程，视网膜胶质细胞活化参与了青光眼性视神经损伤，黄芪干预具有一定的视神经保护作用，其作用机制可能跟抑制视网膜胶质细胞活化有