视神经损伤后突触后密度蛋白-95在大鼠视网膜中的分布及表达研究

目的研究视神经损伤后突触后密度蛋白-95（PSD-95）在神经损伤后sD大鼠视网膜中的定位及表达的变化。方法采用钳夹法制作SD大鼠视神经损伤模型。分别于损伤后1d、3d、5d,7d及14d摘除眼球，以正常大鼠视网膜为对照，应用免疫组织化学方法和Westernblot法检测视神经损伤后PSD-95蛋白水平表达变化；免疫荧光双标技术检测PSD-95的细胞定位情况。结果在正常对照组中，视网膜外丛状层有大量的PSD-95存在。视神经损伤后，PSD-95在视网膜中的表达显著减少，损伤后1d，PSD-95在视网膜外层表达量最低，在损伤后7dPSD-95的表达恢复正常水平并维持到损伤后14d。免疫荧光双标染色结果显示视神经损伤后1dPSD-95与视杆细胞的标记物rhodopsin共定位减少，损伤后7d部分恢复。结论视神经钳夹伤导致了视网膜PSD-95表达量的减少和分布的改变，可能是视网膜神经元损伤后自我保护的一种反应。

Distribution and expression of postsynaptic density protein -95 in rat retina after optic nerve crush.

Objective To study the changes of postsynaptic density protein-95 (PSD-95) location in retina after optic nerve injury.Methods The optic nerve injury model of rats was created by crushing optic nerve at 2 mm retrobulbarly.The method of immunohistochemistry was applied to measure the changes of PSD-95 location in retina at 1 day,3 days,5 days,7 days,and 14 days after crush,and Western blot were used to investigate the changes of PSD-95 expression at the protein levels.The association of PSD-95 and rhodopsin was investigated by immunofluorescence double staining.Results In normal retina,PSD-95 was expressed strongly in outer plexiform layer.The expression of PSD-95 decreased significantly after optic nerve crush.Changes were remarkably in 1 day post-crush ( P ＜ 0.01 ).Expression of PSD-95 was equal with the controll during the 7 to 14 days after crush.Immunofluoresence double staining results showed that PSD-95 co-localized with a photoreceptor-specific marker rhodopsin.Conclusion The expression of PSD-95in the retina decreased and their location changed after optic nerve injury.It suggests that these changes may be likely to protect the degenerative processes of neurons induced by optic nerve injury in the rat retina.