N-甲基-D-天冬氨酸受体1在形觉剥夺性近视豚鼠视网膜上的表达

The expression of NMDAR1 in the retina of guinea pigs with form-deprivation myopia

目的对豚鼠行形觉剥夺建立近视动物模型,观察离子型谷氨酸受体N-甲基-D-天冬氨酸受体1(N-methyl-D-aspartate receptor1,NMDAR1)在近视豚鼠视网膜上的动态表达,探讨其在近视发病机制中的作用。方法60只三色豚鼠随机分为3组:未遮盖组(Ⅰ)、单眼遮盖2周组(Ⅱ)、单眼遮盖3周组(Ⅲ),其中右眼遮盖为实验眼,左眼为自身对照眼。对各组进行视网膜检影和A超测眼轴,分别运用免疫组化及WesternBlotting法检测各组豚鼠视网膜NMDAR1蛋白表达。结果Ⅰ组双眼呈轻度远视状态,双眼眼轴差异无显著性(P>0.05);Ⅱ组实验眼呈轻度近视(-1.583±1.478)D,自身对照眼呈轻度远视(2.500±1.017)D;实验眼眼轴较自身对照眼轻度延长(P<0.05);Ⅲ组实验眼呈中度近视(-3.417±1.169)D,自身对照眼呈轻度远视(1.813±1.072)D;实验眼眼轴较自身对照眼明显延长(P<0.05)。免疫组化显示NMDAR1主要表达在豚鼠视网膜的内核层细胞及神经节细胞。Ⅰ组实验眼视网膜上NMDAR1蛋白含量为0.338±0.314,Ⅱ组实验眼NMDAR1蛋白含量升高为0.464±0.280,Ⅲ组实验眼视网膜NMDAR1蛋白含量明显上调为0.635±0.037;实验眼视网膜上NMDAR1蛋白含量随遮盖时间延长明显上调,与自身对照眼比较差异有显著性(P<0.05)。结论形觉剥夺可明显上调豚鼠视网膜NMDAR1的蛋白表达,形觉剥夺产生的异常视觉信号可能通过刺激谷氨酸的释放、NMDAR1过度生成,参与近视的调控。

Objective To characterize the changes of N-methyl- D-aspartate receptor 1 （NMDAR1） in the retina of the guinea pig with form-deprivation myopia （FDM）and to explore the possible mechanisms of myopia, Methods Form-deprivation myopia was induced in the guinea pig. Three-week-old guinea pigs were divided into three groups：group Ⅰ was untreated; group Ⅱ underwent monocular form-deprivation by facemask for 2 weeks; group Ⅲ was deprived for 3 weeks. The right eyes were form-deprived and the left eyes were used as the control, The refraction and axial length of the eyes were measured. The protein level of NMDAR1 was measured by immunohistochemistry and Western Blot. Results In group Ⅰ , the two eyes had mild hypermetropia and axial length did not differ significantly （P〉0.05）. In group Ⅱ, the deprived eyes had mild myopia（-1.583±1.478）D, and control eyes had mild hypermetropia （2.500±1.017）D; axial length in the deprived eyes was slightly elongated compared to the controls. In group Ⅲ, the deprived eyes had medium myopia （-3.417±1.169）D, and the control eyes had mild hypermetropia （1.813±1.072）D; axial length in the deprived eyes was dramatically elongated compared to the control eyes. The expression of NMDAR1 was mainly located in the inner nuclear layer and ganglion cell layer. In group Ⅰ , the expression of NMDAR1 in the retina of the deprived eyes was 0.338＋0.314; in group Ⅱ , the expression of NMDAR1 was 0.464±0.280; and in group In, the expression of NMDAR1 was 0.635±0.037. The expression of NMDAR1 in the retina of the deprived eyes was significantly different compared to the control eyes （P〈0.05）. Conclusion An effective FDM model was established in guinea pigs with an eye cover. Significant up-regulation can be seen in the expression of NMDAR1 in the FDM retina. The abnormal visual information stimulated the release of glumatic acid and up-regulated the over expression of NMDAR1, which plays an important role in the possible mechanisms of myopia.