地塞米松对兔视神经钳夹伤治疗作用的实验研究

目的：观察地塞米松对家兔视神经钳夹伤后视网膜神经节细胞存活的影响及损伤视神经、视网膜Nogo-A表达的变化。方法：建立兔球后视神经钳夹伤模型，将健康成年家兔分为正常对照组、损伤组、治疗组。分别于损伤后3、7、14d天处死动物，观察单位面积视网膜神经节细胞存活数量及损伤后Nogo-A在视神经与视网膜中的表达变化。结果：视神经损伤后，治疗组视网膜神经节细胞的存活数量高于损伤组及对照组（P〈0.01）；对照组及损伤组损伤后3、7、14d视神经与视网膜中Nogo-A表达增强，至损伤后7d达高峰；治疗组视神经与视网膜Nogo-A表达亦增强，各时间点均弱于损伤组、对照组，差异有非常显著性（P〈0.01）。结论：视神经损伤后，地塞米松能够增加视网膜神经节细胞的存活数量，并下调Nogo基因的表达，这可能是地塞米松的药理作用机制之一。

The experimental study on the therapeutic effect of dexamethasone on the rabbit optic nerve injury by crushing

Objective:To observe the effect of dexamethasone on retinal ganglial cells survival after the rabbit optic nerve injury by crushing and the changes in expression of Nogo-A in injured optic nerve and retina. Methods:Rabbit models of posterior optic nerve injury by crushing were established. Healthy adult rabbits were divided into control group, injured group and treatment group, and then the rabbits were sacrificed on 3, 7 and 14 d after injured respectively. Then the number of survival retinal ganglial cells and the expression of Nogo-A in optic nerve and retina after injured were observed. Results:After the optic nerve injury, the number of survival retinal ganglial cells in treatment group was considerably higher than that in control group and injured group (P<0.01). 3, 7 and 14 days after injured, the expression of Nogo-A increased in optic nerve and retina of control group and injured group, and reached the peak at 7 d after injured. The expression of Nogo-A also increased in optic nerve and retina of treatment group, but was less than that in control group and injured group, the difference was significant (P<0.01). Conclusion:After the optic nerve injury, dexamethasone can increase the number of survival retinal ganglial cells and down-regulate the expression of Nogo gene. It is possible one of the pharmacological mechanisms of dexamethasone.