光学性斜视猫视皮层17区突触超微结构及神经生长因子表达的变化

发布时间：2018-05-16 15:25

本文选题：突触 + 超微结构　；参考：《济南大学》2012年硕士论文

【摘要】：目的观察融合功能缺失的光学性斜视猫视皮层17区突触超微形态结构以及神经生长因子（nerve growth factor，NGF）表达的变化，探讨双眼融合功能的结构基础和影响因素。方法将4周龄普通家猫随机分为正常对照组、光学性斜视组及弱视组，于视觉可塑性关键期内（4周龄），分别通过双眼佩戴基底向内的15△三棱镜和缝合右眼睑裂，建立光学性斜视模型及单眼形觉剥夺性弱视模型，待6个月龄时，通过VEP检测，进行动物筛选，并参照猫大脑立体定位图谱，对三组视皮层17区进行取材、固定、包埋和电镜标本制作，进行半薄和超薄切片，应用透射型电子显微镜由视皮层Ⅰ层至Ⅵ层依次摄取15,000倍和30,000倍照片，，测量突触间隙的宽度、突触后致密物厚度、突触后膜的弦长和弧长。经取材、固定、脱水、包埋等制作石蜡标本，进行免疫组织化学染色，观察NGF表达的变化。所有实验数据采用SPSS17.0统计软件进行统计学分析。结果 1. P-VEP检测结果：正常组P100波波形规则，有明显波峰，双眼振幅大于或等于单眼振幅的2倍；光学性斜视组单眼P100波振幅和潜时与正常组差异无统计学意义（P0.05），双眼振幅小于单眼振幅；弱视组左眼P100波振幅和潜时与正常组差异无统计学意义（P0.05），但右眼P100波振幅小于正常组与斜视组，潜时长于正常组与斜视组，差异有统计学意义(P0.05)，双眼振幅小于单眼振幅。 2．甲苯胺蓝染色结果：正常组和光学性斜视组视皮层17区分层清晰，由浅至深共分为六层，正常组比光学性斜视组内颗粒层发达，细胞更为密集，多数是星形细胞；弱视组视皮层未见明显分层，细胞密度较低，且以染色浅，体积小等不成熟细胞为主。 3．突触超微形态结构的变化：正常组和光学性斜视组突触间隙、突触后膜界面曲率、突触后膜致密物厚度的差别无统计学意义（P0.05）。弱视组较正常组和光学性斜视组的突触间隙增宽、界面曲率减小、突触后膜致密物增厚，差异有统计学意义(P0.05)。 4．免疫组织化学染色结果：各组视皮层17区各层均可见NGF阳性细胞，光学性斜视组和弱视组较正常组免疫阳性神经元着色淡，阳性神经元数减少，差异有统计学意义(P0.05)；弱视组较斜视组更加减少，差异有统计学意义(P0.05)。结论 1．在猫的视觉可塑性关键期内建立光学性斜视，虽然能够破坏融合功能，但与单眼形觉剥夺性弱视不同，未引起视皮层17区突触结构各项参数的变化。说明融合功能破坏与单眼形觉剥夺性弱视的发生机制不同。 2．光学性斜视和单眼形觉剥夺性弱视，均使视皮层17区NGF的表达下降，弱视组表达较斜视组更加减少，证明NGF的表达与双眼视觉功能存在密切联系。
[Abstract]:Purpose The ultrastructure of synapses and the expression of nerve growth factor (NGF) in optic strabismus of cats were observed, and the structural basis and influencing factors of binocular fusion function were discussed. Method The 4-week-old domestic cats were randomly divided into normal control group, optical strabismus group and amblyopia group. During the critical period of visual plasticity, 4-week old cats were treated with 15 prism and suture of right eyelid fissure. An optical strabismus model and a monocular form deprivation amblyopia model were established. At the age of 6 months, the animals were screened by VEP, and three groups of visual cortex were selected and fixed according to the stereotaxic map of the cat's brain. The embedded and electron microscopic specimens were made and made into semi-thin and ultra-thin sections. Using transmission electron microscope (TEM), 15000 and 30000 times photographs were taken from layer I to layer VI of the visual cortex, respectively. The width of synaptic space and the thickness of postsynaptic dense substance were measured. The chord length and arc length of postsynaptic membrane. Paraffin wax specimens were made by sampling, fixation, dehydration and embedding. The expression of NGF was observed by immunohistochemical staining. All experimental data were statistically analyzed by SPSS17.0 software. Result 1. The results of P-VEP: in normal group, the P100 wave waveform was regular, there was obvious wave peak, and the binocular amplitude was more than or equal to 2 times of the monocular amplitude. There was no significant difference in P100 wave amplitude and latent time between optical strabismus group and normal group (P 0.05), but the amplitude of binocular was smaller than that of single eye. There was no significant difference in P100 wave amplitude and latent time between the amblyopia group and the normal group. However, the P100 wave amplitude of the right eye was lower than that of the normal group and strabismus group, and the latent time was longer than that of the normal group and strabismus group. The difference was statistically significant (P 0.05), and the amplitude of both eyes was less than that of the single eye. 2. The results of toluidine blue staining showed that the 17 layers of visual cortex in normal group and optical strabismus group were clear and divided into six layers from shallow to deep. The granular layer of normal group was more developed than that of optical strabismus group, and most of them were astrocytes. In the amblyopia group, the visual cortex was not stratified, the cell density was low, and immature cells, such as light staining and small size, were dominant. 3. Ultrastructural changes of synapses: there was no significant difference in synaptic space, postsynaptic membrane interface curvature and the thickness of dense substance of postsynaptic membrane between normal group and optical strabismus group (P 0.05). Compared with the normal group and the optical strabismus group, the synaptic gap widened, the curvature of the interface decreased and the density of the postsynaptic membrane increased in the amblyopia group. The difference was statistically significant (P 0.05). 4. The results of immunohistochemical staining showed that NGF positive cells were found in all layers of the visual cortex in each group. The immunoreactive neurons in the optic strabismus group and the amblyopia group were lighter than those in the normal group, and the number of the positive neurons was decreased. The difference was statistically significant (P 0.05), and that of amblyopia group was lower than that of strabismus group (P 0.05). Conclusion 1. The establishment of optical strabismus in the critical period of visual plasticity in cats, although it can destroy the fusion function, is different from the form deprivation amblyopia, and does not cause the changes of the synaptic structure parameters in the 17 region of the visual cortex. It suggests that the mechanism of fusion dysfunction is different from that of monocular form deprivation amblyopia. 2. Both optical strabismus and monocular form deprivation amblyopia decreased the expression of NGF in area 17 of visual cortex, and the expression of NGF in amblyopia group was much lower than that in strabismus group, which proved that the expression of NGF was closely related to binocular visual function.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R777.41

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