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目的 研究胶质细胞源神经营养因子(GDNF)联合甲泼尼龙(MP)对视神经轴突切断的大鼠视网膜兴奋性氨基酸转运蛋白-1(EAAT-1)和谷氨酰胺合酶(GS)表达及对视网膜神经节细胞(RGCs)存活与轴突再生的影响.方法 建立大鼠右眼视神经轴突切断(ONA)模型52只,随机分为Ⅰ、Ⅱ两组,每组26只.Ⅰ组给予甲泼尼龙10 mg/kg/d×5 d静脉注射;及GDNF 2μg玻璃体内注射,术后7d重复注射.Ⅱ组相同时间点给予等体积生理盐水注射.对侧眼作为各自正常对照组不予注射.Western-blot检测各组术后14 d、21 d视网膜EAAT-1和GS的表达;霍乱毒素β亚单位顺行标记RGCs和视神经纤维并定量分析.结果 RGCs逆行标记显示视神经轴突被完全切断.Ⅰ组的EAAT-1和GS表达高于Ⅱ组.14 d,Ⅰ组的RGCs密度高于Ⅱ组.Ⅰ组、Ⅱ组的视神经的荧光强度在14 d及21d的差异无统计学意义.结论 GDNF联合用泼尼龙能促进视神经轴突切断后大鼠视网膜EAAT-1和GS的表达,并短暂促进RGCs存活,但不能促使RGCs轴突再生.“,”Objective To study the effects of Glial cell derived neurotrophic factor (GDNF) combined with methylprednisolone(MP) on the expression of excitatory amino acid transporter-1 (EAAT-1) and glutamine synthetase(GS),the survival of retinal ganglion cells (RGCs) and the axon regeneration of rats after optic nerve axotomy(ONA).Methods Fifty-two rats ONA models were established,and divided into two groups randomly with 26 rats in each group.Right eyes of group Ⅰ were injected intravitreously 2 μg GDNF after ONA immediately,which was repeated at 7 days after ONA,and were injected intravenously MP 10 mg/kg/d for 5 days.Right eyes of group Ⅱ were received equal volume of normal saline respectively at the same time.The left eyes of each group were intact,and served as normal control group respectively.At 14 and 21 days after ONA,the expression of EAAT-1 and GS of each group was tested with Western-blot,and the density of survived RGCs and the fluorescence intensity of optic nerve sections were analyzed by anterogradely labeling with subunit β of cholera toxin conjugated fluorescein isothiocyanate (CTB-FITC).Results RGCs retrograde showed that the optic nerve axotomy was complete.The expression of GS and EAAT-1 of group1 was higher significantly than that of group Ⅱ at 14 and 21 days after ONA.The density of RGCs of group Ⅰ at ONA 14 d was increased compared with that of group Ⅱ.But there was no significant difference between the fluorescence intensity of CTB-FITC of two groups.Conclusion Exogenous GDNF injected intravitreously combined with MP injected intravenously can enhance the expression of GS and EAAT-1,increase the survival of RGCs temporarily,but can not promote axon regeneration of RGCs after ONA.