【作者】 化志娟；

【导师】 江春光； 胡竹林； 许静； 辛志坚；

【作者基本信息】 昆明医学院 ， 眼科学， 2010， 硕士

【摘要】 研究目的本研究的目的主要是观察形觉剥夺性弱视动物模型及对它们应用左旋多巴治疗后,视皮质17区生长相关蛋白GAP-43的表达,从而探讨形觉剥夺性弱视形成的可能机制及左旋多巴对形觉剥夺性弱视视觉功能恢复作用的可能机制。研究方法50只4周龄幼猫,随机分为正常组、剥夺组、对照组、低剂量组及高剂量组共5组,每组10只。后四组于4周龄时行左眼睑缝合术,8周龄时经PVEP检测确定为弱视形成后:剥夺组处死所有动物;对照组打开眼睑反向缝合右眼睑4周做遮盖治疗模型;低剂量组与高剂量组打开眼睑分别予以20mg/kg、80mg/kg左旋多巴溶液灌胃给药,每日一次,持续4周,行PVEP检测后处死动物。正常组于8周龄时行PVEP检测后随机处死5只,剩余5只于12周龄时行PVEP检测后处死。所有动物处死后取右脑半球视皮质17区行HE及免疫组织化学染色观察GAP-43蛋白免疫阳性细胞数。研究结果（1）电生理结果:PVEP主要以P₁₀₀波振幅及潜时改变为特点。8周龄时,剥夺组、低剂量组、高剂量剥夺眼P₁₀₀波振幅比对侧眼及同周龄正常组幅值降低,潜时延长（P＜0.05）;12周龄时,低剂量组剥夺眼P₁₀₀波振幅增高,与对侧眼及同周龄正常组相比无差异（P＞0.05）,而P₁₀₀波潜时则未达到正常（P＜0.05）;高剂量组剥夺眼P₁₀₀波振幅增高、潜时缩短,与对侧眼及同周龄正常组相比无差异（P＞0.05）。（2）光镜下,HE染色结果显示:剥夺组视皮质神经元的数目有所减少,形态不规则,体积大小不一,胞浆突起变短或消失,有些胞核变小、变暗。应用左旋多巴后,高剂量组神经元大部分恢复,细胞体积增大,轴突也有一定程度的恢复;对照组、低剂量组都仅有少数的神经元有恢复。（3）免疫组化结果:剥夺组较正常组GAP-43表达明显减少,差异有显著性（P＜0.05）;高剂量组GAP-43表达与正常组基本相似,差异无显著性（P＞0.05）;对照组、低剂量组和正常组相比有显著性差异（P＜0.05）。结论（1）剥夺组较正常组视皮质17区GAP-43表达明显减少,提示GAP-43可能在形觉剥夺性弱视形成过程中起一定的作用。（2）应用左旋多巴干预后视皮质17区GAP-43表达增多,提示左旋多巴对形觉剥夺性弱视视功能改善的机制可能是通过GAP-43表达的改变而实现的。更多还原

【Abstract】 ObjectiveTo investigate expression of GAP-43, a growth associated protein, in 17 Area of visual cortex in monocular form-deprived amblyopia model and the model treated with levodopa. The possible mechanism of monocular form-deprived amblyopia and therapeutic effect of levodopa are discussed.MethodsFifty kittens of 4-week-old were randomly divided into five groups: normal group, monocular form-deprived group, control group, low-dose group, high-dose group, each group had ten cats. The left eyelids were sutured in behind four groups at 4-week-old.The kittens were raised for 4 weeks and were assured the formation of amblyopia by PVEP. Then ten kittens were killed in monocular form-deprived group; the right eye of the kittens in the control group were sutured as a model of patch therapy for 4 weeks; the kittens in the low-dose group and the high-dose group were daily received with levodopa of 20mg/kg and 80mg/kg for 4 weeks separately.5 kittens were killed at 8-were-old and others were killed at 12-week-old by PVEP in normal group. The visual cortex 17 area of right brain were obtained to observe morphology and immunohistochemistry in all kittens.Result（1）Electrophysiology: At 8-week-old, the latency and ampitude of P₁₀₀ of PVEP was significantly delayed and declined in monocular deprived eyes of monocular form-deprived group control group, low dose and high dose group, compared with fellow eyes and normal eyes （P<0.05）. At-12-week-old,the amptitude of low dose group in monocular deprived eyes is no significant difference compared with fellow eyes and normal eyes （P>0.05）;but the lantency did not recover to normal（P<0.05）.In high group, the amptitude and lantency recovered to normal, presenting a insignificant difference compared with fellow eyes and normal eyes（P>0.05）. （2）Morphology: compared with the normal group, numbers of neuron in the form-deprived group decrease and most of them, appearance of neuron is not regular, volume of neuron is unequal, ecphyma of neuron is getting shorter or disappearance. Some nucleus of neurons are smaller and darkening. After administration of levodopa, most of neurons are recovered and the volume of neuron is bigger and the axon is recovered in the high-dose group .But in the low-dose group and the control group, few of neurons recovered.（3）Immunohistochemistry: Compared with the normal group, the expression of GAP-43 is significant difference in the form-deprived group （P<0.05）. The expression in high-dose group is similar to the normal group and no significant difference is found （P>0.05） . Compared with the normal group, there is significant difference between the control group and the low-dose group （P<0.05）.Conclusions（1）There is significant increase of the expression of GAP-43 in the form-deprived group compared with the normal group. It indicates that GAP-43 may play a important role in formation of amblyopia.（2）There is significant decrease of the expression of GAP-43 in the high-dose group with levodopa. It suggests that the improved visual function of amblyopia may be brought into effect through GAP-43 expression.更多还原