剥夺性弱视猫外侧膝状体c-fos基因及Fos蛋白表达

为研究生后关键期内,正常猫及剥夺性弱视猫外侧膝状体神经元功能形态的变化规律,对正常视发育敏感期的幼猫行左眼睑缝合术,造成剥夺性弱视模型,采用Nissl染色法及电镜观察正常猫及剥夺性弱视猫外侧膝状体神经元的形态改变,并用免疫组化和原位杂交技术检测Fos蛋白及cfos基因的表达情况。结果显示:(1)剥夺猫剥夺层外侧膝状体神经元的截面积比非剥夺层及正常猫的明显变小,差异有显著性(P<0.05);(2)超微结构显示:剥夺性弱视猫的剥夺层出现大量变性的细胞,剥夺4周时最为显著;(3)正常猫外侧膝状体神经元Fos蛋白和cfos原位杂交的阳性细胞数及OD值随着时间的延长而降低。同龄猫剥夺层外侧膝状体Fos蛋白和cfos原位杂交阳性细胞数及OD值较正常猫减少(P<0.05)。结果提示:猫视觉的可塑性敏感期为生后4周到8周。剥夺性弱视猫外侧膝状体剥夺层及非剥夺层神经元形态及功能与正常猫相比较均发生改变。Fos法可以成为衡量弱视猫外侧膝状体兴奋性状态与形态学定位相结合的实验方法,但必须注意神经可塑性对其的影响。

THE EXPRESSION OF FOS PROTEIN AND c-fos GENE IN LATERAL GENICULATE NUCLEUS OF CAT AFTER MONOCULAR DEPRIVATION

To observe the expression of Fos protein and c-fos gene in lateral geniculate nucleus (LGN) in monocular deprivation cats. The left eyelids of 4-week-old rats were sutured. The morphological changes of neurons in LGN were examined by Nissl staining and electron microscope, the changes of Fos protein and c-fos gene expression in LGN were also observed by immunohistochemistry and in situ hybridization. The results showed that (1) The size of cells in the LGN of the deprived eyes was smaller than that of undeprived and normal eyes (P<0.05); (2) The ultrastructure showed that a great deal of the visual deprived cells degenerated, and reached the peak after deprived for 4 weeks; (3) In LGN of normal kittens, Fos protein and c-fos gene expression was reduced with the age increased. The number of positive cells and the OD of Fos protein and c-fos gene of deprived eyes were lower than those of normal cats at the same age (P<0.05). The results suggest that the most plasticity of visual acuity is from 4 to 8 weeks after birth in cats. Fos protein and c-fos gene expression in LGN has changed significantly, and the method of Fos immunohistochemistry and c-fos in situ hybridization is useful in observing the neural activity and the morphological changes of the LGN of the amblyopic cats.