不同时限单眼斜视和剥夺猫视觉系统的神经生长因子表达研究

Studies on mechanism of gene expression of NGF in the visual system of kittens within and the end of crucial periods

目的 :研究和探讨敏感期内、期末不同时限单眼斜视和剥夺猫模型视觉系统神经生长因子(nervegrowthfactor,NGF)可塑性变化规律 ,可望能为临床寻找有效预防和治疗斜视和剥夺性弱视提供参考依据。方法 :用免疫细胞化学SABC技术染色和计算机图像分析检测NGF在正常 (N)、敏感期内单眼斜视和剥夺 (MS1和MD1 )及敏感期末单眼斜视和剥夺 (MS2和MD2 )幼猫同侧视皮质、外侧膝状体组织切片下的变化规律 ,其结果进行统计学处理。结果 :①在光镜下 ,NGFmRNA表达蛋白在正常眼同侧视皮质 1 7区存在于 2 -6层。阳性神经元呈浓褐色 ,胞核、胞浆同时着色深 ,在MS1和MD1 ,NGF免疫阳性神经元着色较淡。阳性神经元数减少。在外侧膝状体 (LGN)三层均有NGF免疫阳性神经元 ,阳性细胞核浓染 ,胞浆呈深棕褐色 ,其轴、树突不明显并以大细胞为主。在MS1和MD1眼输入层NGF阳性细胞染色淡 ,胞体小及密度减少。上述NGF蛋白免疫阳性浓度及细胞数密度变化为 ,在视皮质 1 7区Ⅳ层 ,N与MS1及MD1组比较差异具有显著性 (P <0 0 5,P <0 0 0 1 ) ,而与MS2及MD2组比较差异无显著性。在外侧膝状体 ,由N眼输入层与由MS1和MD1眼相应输入层比较差异有显著性 (P <0 0 5,P <0 0 1 ) ,N眼输入层与MS2和MD2眼输入层比较差异则无显著性 (P >0 0 5)。

Objective:Distribution of gene expression of NGF in the visual system of the normal and experimental groups have been investigated and the plastic changes in neurons of the visual system of normal(N),monocular strabismus(MS) and monocular deprivation(MD) kittens at different time limit are discussed at the field of tectology and neurocyto molecular biology.Methods:Changes in number density(ND) and integral optical density(IOD) immunopositive concentration of immunopositive neurons of gene expression of nerve growth factor(NGF) in the layer Ⅳ of visual cortex area 17 and the laminas of lateral geniculate nuclus inputs from N,MS1 and MD1(at the age of 4 6wk),MS2 and MD2(at the age of 10 12wk) eyes were analysed with immunocytochemistry,SABC technique and by Computer Image Analysis System.Results:showed that there are immunopositive neurons which appear as brown colour in the layer I,Ⅱ/Ⅲ,Ⅳ,Ⅴ and Ⅵ of visual cortex area 17 and the laminas of lateral geniculate muclus inputs from the experimental eyes.NGF protein of immunopositive cellular number and concentration in the layer Ⅳ of visual cortex area 17 and the laminas of lateral geniculate nuclus inputs from the experimental eyes are the most in N group and the lowest in MS1 and MD1 groups.However,N/MS2 and N/MD2 by comparison have no significant difference.Conclusions:NGF may make an important role in differentiation,development and forming of synapses united each other of visual system.The studies indicated that changes in gene expression and function of NGF mRNA are affected by visual experiences.So,visual disturbance and form deprivation may lead to reduction for gene expression of NGF protein.Therefore,biological function and activity of NGF may be based on whether inputs from visual information of retinae and experimental eyes of retinal activity are normal or not.