视觉发育关键期单眼形觉剥夺对大鼠视功能和视皮层PKCζ蛋白表达的影响

目的　探讨视觉发育关键期单眼形觉剥夺对大鼠视功能和视皮层PKCζ蛋白表达的影响。方法　选取出生后13 d SPF级Long Evans大鼠28只,利用随机数字表法将大鼠随机分为两组:正常对照组、弱视模型组，每组14只，以右眼作为实验眼。建立大鼠多维度弱视模型，采用视觉诱发电位验证弱视模型的建立，HE染色观察大鼠视皮层形态结构，视觉悬崖实验检测大鼠立体视功能，计算每只大鼠的辨别指数，Western blot检测大鼠视皮层中PKCζ蛋白的表达。结果　与正常对照组相比，弱视模型组大鼠右眼（剥夺眼）的P2波潜伏期明显延长，P2波振幅明显降低，差异均有统计学意义(均为P<0.05) 。两组大鼠视觉悬崖实验检测结果显示，正常对照组大鼠探索行为轨迹集中在右侧(非悬崖侧)，而弱视模型组大鼠探索行为轨迹紊乱，探索区域大多分布在左侧 (悬崖侧)。弱视模型组大鼠辨别指数明显低于正常对照组 (P<0.05)。正常对照组大鼠视皮层神经元数量丰富，结构完整，未出现明显神经元变性和坏死；弱视模型组大鼠视皮层神经元数量明显减少，结构不完整，出现不同程度的胞体固缩。弱视模型组大鼠左侧视皮层PKCζ蛋白相对表达量明显低于正常对照组（P<0.01）。结论　在视觉发育关键期单眼形觉剥夺可造成大鼠视皮层结构的改变和视功能严重损害，视皮层PKCζ蛋白表达水平下降。

Effects of monocular form deprivation on visual function and protein kinase C-zeta expression in the visual cortex of rats during the critical period of visual development

Objective　To explore the effects of monocular form deprivation on the visual function and expression of protein kinase C-zeta (PKCζ) in the visual cortex of rats in their critical period of visual development. Methods　Totally 28 specific pathogen-free Long Evans rats (13 d) were selected and randomly divided into the normal control group and the amblyopia model group, with 14 rats in each group. The right eye was chosen as the experimental eye. The multi-dimensional amblyopia model was established and verified with visual evoked potential. The hematoxylin and eosin staining was used to observe the morphological structure of the rat visual cortex, the visual cliff test was used to test the stereoscopic vision function of the rats, and Western blot was used to detect the expression of PKCζ in the visual cortex of rats. The discrimination index (DI) of each rat was calculated. Results　Compared with the right eyes of rats in the normal control group, the latency of P2 wave in the rights eyes (deprived eyes) of rats in the amblyopia model group was significantly prolonged, and the amplitude of P2 wave was significantly decreased (both P<0.05). The visual cliff test results showed that the behavioral trajectories of the rats in the normal control group were concentrated on the right side (non-cliff side). The behavioral trajectories of the rats in the amblyopia model group were disordered, and the exploration area was mostly distributed on the left side (cliff side). The DI of rats in the amblyopia model group was significantly lower than that of the normal control group (P<0.05). The visual cortex of rats in the normal control group had abundant neurons with complete structures and no obvious degeneration and necrosis. In the amblyopia model group, the number of neurons in the visual cortex reduced significantly with incomplete structures and various degrees of soma pyknosis. The relative expression level of PKCζ in the left visual cortex of rats in the amblyopia model group was significantly lower than that of the normal control group (P<0.01). Conclusion　The monocular form deprivation in the critical visual development period of rats induces changes in the structure of the visual cortex, causes severe damage to the visual function, and decreases the expression level of PKCζ in the visual cortex.