嘌呤受体P2X_7激活介导大鼠视网膜神经节细胞死亡的实验研究  

An Experimental Study on Lethal Effect of P2X_7 Receptor Activation on Rat Retinal Ganglion Cell

作　　者：张秀兰[1] 张梅[1] 葛坚[1] Claire H.Mitchell 

机构地区：[1]中山大学中山眼科中心,广东广州510060 [2]宾夕法尼亚大学医学院生理系,美国费城19104

出　　处：《中山大学学报（医学科学版）》2006年第2期130-134,共5页Journal of Sun Yat-Sen University:Medical Sciences

基　　金：国家自然科学基金资助项目(30471850);广东省自然科学基金资助项目(04009334);教育部回国人员科研启动基金资助项目(200555)

摘　　要：【目的】研究嘌呤受体P2X7激动剂、拮抗剂对大鼠视网膜神经节细胞(RGCs)的影响。【方法】(1)对新生Long-Evan大鼠进行上丘注射荧光标记物Aminostilbamidine以标记RGCs,检测P2X7激动剂BzATP(0、50、100、500!mol/L)和特异性拮抗剂OxATP(100!mol/L)对体外培养RGCs存活率的影响;(2)体外培养未经Aminostilbamidine标记的新生大鼠RGCs,以10!mol/L钙离子(Ca2+)荧光染料Fura-2标记后,利用Ca2+影像测定仪分别测定P2X7激动剂BzATP(50!mol/L)和拮抗剂OxATP(100!mol/L)对RGCs胞内Ca2+浓度的影响。【结果】P2X7受体激动剂BzATP可引起体外培养的RGCs死亡,反应呈剂量依赖性,EC50=35!mol/L。在50!mol/L浓度下,BzATP约杀死30%的RGCs;而100!mol/LOxATP则可明显减轻BzATP对RGCs的毒性作用,使RGCs存活率从77%±4%提高至96%±3%(P<0.001)。BzATP可引起RGCs胞内Ca2+持续升高,在50!mol/L浓度下可使胞内Ca2+升高(1022±113)nmol/L。在OxATP作用下,BzATP介导的Ca2+升高幅度显著降低,仅升高(63±13)nmol/L(P<0.001)。【结论】嘌呤能P2X7受体激活可导致大鼠视网膜神经节细胞死亡和胞内钙离子浓度升高。[ Objective ] To study the effects of the agonist and the antagonist of the purinergic P2X7 receptor on rat retinal ganglion cells （RGCs）. [Methods] （1） Long-Evan neonatal rats were back labeled with Aminostilbamidine to identify RGCs. The effect of P2X7 receptor stimulation on RGCs cell viability was then examined using P2X7 receptor agonist BzATP （0, 50, 100, 500 μmol/L） and antagonist OxATP （100 μmol/L）. （2） Retinal ganglion cells were dissociated from the retinas of unlabeled neonatal rats and were loaded with Fura-2, an intracellular calcium indicator. P2X7agonist BzATP （50μmol/L）, antagonist OxATP （100 μmol/L ） were applied to RGCs to examine their effects on intracellular Ca^2＋ levels using Ca^2＋ imaging system. [ Results ] P2X7 receptor agonist BzATP killed RGCs in a concentration-dependent pattern with a ECs of 35 μM. Under the concentration of 50μmol/L, BzATP could kill about 30% of the RGCs. Cell death was prevented by P2X7 antagonists OxATP, increasing the cell viability from 77% ± 4% to 96% ±3% （P〈 0.001）. BzATP （50 μmol/L） led to a large, sustained increases of intracellular Ca^2＋ （1022 ± 113 nmol/L）. Calcium influx triggered by BzATP was attenuated by pre- and co-incubation of P2X7 antagonist OxATP with a slight increase of （63± 13） nmol/L （P〈 0.001）. [Conclusions] The activation of purinergic P2X7 receptor can cause rat retinal ganglion cell death and the increase of intracellular calcium.

关 键 词：视网膜神经节细胞 P2X7受体 钙离子 

分 类 号：R77[医药卫生—眼科]