【作者】 代春华；

【导师】 宫华青；

【作者基本信息】 青岛大学 ， 眼科学， 2010， 硕士

【摘要】 目的：研究单眼形觉剥夺后反缝对成年期弱视大鼠视皮层17区突触可塑性的影响。探讨成年期视皮层突触可塑性的机制。方法：将Wistar大鼠分为正常组、弱视组和反缝组。分别饲养至相应时间点时取左侧大脑视皮层17区。应用免疫组织化学法检测突触后GABAAR a 1和GluR2亚基的表达水平。透射电子显微镜对视皮层17区第Ⅳ层连续摄取3,000倍照片,局部定位放大后进行突触计数。随机摄取30,000倍照片,使用Image Proplus 6.0分析软件对突触间隙宽度、突触后致密物厚度、突触界面曲率进行测量。所有实验数据采用SPSS13.0统计软件包进行统计学处理。结果：(1)免疫组织化学结果：P11w时,弱视组和反缝组大鼠视皮层17区GABAARal的表达较正常组明显减少(P＜0.001),弱视组较反缝组也明显减少(P＜0.001)。P13w时,弱视组较反缝组及正常组明显减少(P＜0.001),而反缝组与正常组比较无明显差别(P＝0.496),两个时间点弱视组GluR2的表达较反缝组和正常组均明显增强(P<0.001),反缝组较正常组均明显较少(P＜0.001)。(2)突触超微形态结构变化：P11w与P13w时,3组大鼠视皮层突触数量的差异均有统计学意义,弱视组突触数量较反缝组和正常组明显减少,反缝组较正常组也减少(P＜0.01)。弱视组与反缝组及正常组比较,P11w和P13w时都是突触间隙明显增宽,突触后致密物明显增厚,突触界面曲率明显变小(P＜0.01)。反缝组与正常组比较,P11w时,突触间隙增宽,突触后致密物增厚,突触界面曲率变小(P<0.05)；而P13w时,差异无统计学意义(P>0.05)。结论：视觉系统的可塑性不仅存在于视觉发育的关键期以内,在关键期之后仍然存在。反缝干预能从结构和功能两方面来使成年大鼠视皮层的可塑性得以改善和恢复。更多还原

【Abstract】 ObjectiveTo explore the effect of reverse suture after monocular deprivationon synaptic plasticity at the 17th area of amblyopic rat visual cortex after the critical period of visual development, as well as the possible mechnism of synaptic plasticity in adult rat visual cortex.MethodsThe Wistar rats were divided into normal group, amblyopia group and reverse-suture group, and were sacrificed to obtain the 17th area of the left visual cortex at corresponding time points. The expression of GABAARα1 and GluR2 subunit was detected by immunohistochemistry. The changes of synaptic ultra-structure were observed by electron microscopy. Photos of 3,000 magnification were continuously captured from layer VI of the primary visual cortex for counting the number of synapses in 3,000 Multiplying Factor. Photos of 30,000 Multiplying Factor were captured randomly. Image Proplus 6.0 was used to measure the width of synaptic cleft, the thickness of post-synaptic density and synaptic interface curvature. SPSS 13.0 was used for statistical analysis.ResultsBy immunohistochemistry, weaker expression of GABAARal subunit could be found in the amblyopia group and reverse-suture group than in the normal group at P11w (P<0.001).The expression in the amblyopia group was weaker than the reverse-suture group (P<0.001). At P13w, the weaker expression could also be found in the amblyopia group than the reverse-suture group and the normal group(P<0.001), but there was no significant difference between the reverse-suture group and the normal group (P=0.496). The expression of GluR2 was stronger in amblyopia group than in reverse-suture group and normal group (P<0.001), weaker expression was seen in reverse-suture group than in normal group (P<0.001), either at Pllw or at P13w. Regarding changes of synaptic ultra-structure, there was significant difference among three groups both at Pllw and at P13w. The quantity of synapses in the amblyopia group reduced significantly compared with the reverse-suture group and the normal group, the quantity in the reverse-suture group was reduced than the normal group (P<0.01). The synaptic cleft was widened, synaptic PSD was thickened and interface curvature became smaller in the amblyopia group than the reverse-suture group and the normal group both at P11w and at P13w (P<0.05). The same result was taken when the reverse-suture group was compared with the normal group at P11w(P<0.05), but there was no significant difference at P13w(P>0.05). ConclusionThe plasticity of visual cortex exists not only in the critical period but also after the critical period of visual development. The reverse suture after monocular deprivation could improve the synaptic plasticity in visual cortex of adult rats in structure and function.更多还原