Liu Xiaohong, Huang Ping, Wang Jing, Yang Zijian, Huang Shouyue, Luo Xunda, Qi Jin, Shen Xi, Zhong Yisheng
Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, Shanghai, China.
Shanghai Key Laboratory for Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, Shanghai, China.
Invest Ophthalmol Vis Sci. 2016 Mar;57(3):776-86. doi: 10.1167/iovs.15-18024.
We investigated the effect of A2A receptor (A2AR) antagonist on microglial activation and retinal ganglion cell (RGC) survival under chronic ocular hypertension (COH), and explored the relationship between microglial activation and RGC survival by means of in vitro and in vivo experiments.
An animal model of COH was induced in one eye of male Sprague-Dawley (SD) rats by ligation of three episcleral veins. The survival of RGCs and the activation of microglia under COH without or with intravitreous injection of A2AR antagonist ZM241385 were assessed by fluorescent labeling, real time PCR and Western blot. ELISA was used to measure the secretion of inflammatory mediators by microglia when glutamate and/or ZM241385 was added into the culture system.
Compared to the baseline, RGC density 2 weeks after COH induction decreased at the central (2436 ± 143 cells/mm2 pre- and 2130 ± 148 cells/mm2 post-COH induction) and peripheral (2219 ± 140 cells/mm2 pre- and 1953 ± 142 cells/mm2 post-COH induction) retina. The microglia changed their ramified morphology to an amoeboid form with increase in TNF-α and IL-1β expression after COH. These changes, however, were ameliorated with intravitreous ZM241385 (RGC density only dropped to 2287 ± 135 cells/mm2). The upregulation of those proinflammatory cytokines secreted by microglia in vitro under high concentration of glutamate was downregulated when ZM241385 was added into the culture system.
A2AR antagonist ZM241385 could reduce the activation of microglia and downregulate the proinflammatory cytokines expression under the conditions of COH and high concentration of glutamate, which may be one of the mechanisms that protected RGCs in experimental glaucoma.
我们研究了A2A受体（A2AR）拮抗剂对慢性高眼压（COH）状态下小胶质细胞活化及视网膜神经节细胞（RGC）存活的影响，并通过体内和体外实验探究小胶质细胞活化与RGC存活之间的关系。
通过结扎雄性Sprague-Dawley（SD）大鼠一只眼睛的三条巩膜静脉诱导建立COH动物模型。通过荧光标记、实时PCR和蛋白质印迹法评估在未注射或玻璃体腔内注射A2AR拮抗剂ZM241385的COH状态下RGC的存活情况以及小胶质细胞的活化情况。当向培养系统中添加谷氨酸和/或ZM241385时，使用酶联免疫吸附测定法（ELISA）检测小胶质细胞分泌的炎症介质。
与基线相比，诱导COH后2周，中央视网膜（诱导前2436±143个细胞/mm²，诱导后2130±148个细胞/mm²）和周边视网膜（诱导前2219±140个细胞/mm²，诱导后1953±142个细胞/mm²）的RGC密度降低。COH后，小胶质细胞由分支状形态转变为阿米巴样形态，肿瘤坏死因子-α（TNF-α）和白细胞介素-1β（IL-1β）表达增加。然而，玻璃体腔内注射ZM241385可改善这些变化（RGC密度仅降至2287±１35个细胞/mm²）。当向培养系统中添加ZM241385时，体外高浓度谷氨酸刺激下小胶质细胞分泌的那些促炎细胞因子的上调受到抑制。
A2AR拮抗剂ZM241385可在COH和高浓度谷氨酸条件下减少小胶质细胞的活化并下调促炎细胞因子的表达，这可能是实验性青光眼中保护RGC的机制之一。
