甘肃鼢鼠（Myospalax cansus）视觉系统细胞凋亡

【作者】 贺莹；

【导师】 李金钢；

【作者基本信息】 陕西师范大学 ， 动物学， 2010， 硕士

【摘要】 视觉系统在动物通讯中占据着主导地位,其适应进化机制一直是动物行为学研究的焦点。生活在特殊环境中的动物,其视觉系统在进化过程中表现出来的显著差异更是引人注目。甘肃鼢鼠(Myospalax cansus)由于终年生活在地下黑暗的洞道,生活的空间格局对其视觉系统的结构、生理机能产生了深刻的影响。由于长期的适应进化,其视觉系统的形态结构和功能发生了巨大的变化,其中最为显著的是眼变小,视觉退化。研究表明,甘肃鼢鼠视网膜结构完整,那么为何甘肃鼢鼠视觉退化,其过程如何目前仍不清楚,为此,本研究运用细胞学、免疫组织化学等方法对甘肃鼢鼠视觉系统细胞凋亡作以研究。结果如下：1.甘肃鼢鼠从0日龄开始其视网膜内就出现凋亡细胞,凋亡指数为：26.9±0.441%,这说明甘肃鼢鼠从出生其视网膜就伴随着细胞凋亡。凋亡细胞主要出现在视网膜视杆视锥层以及向内的各层,特别是外核层、内核层利神经节细胞层,这说明视杆视锥层及其向内的各层细胞是视觉通路中的主要神经元。2.0日龄、3日龄、5日龄、7日龄、9日龄、11日龄、14日龄甘肃鼢鼠视网膜细胞凋亡指数逐渐增大,14日龄细胞凋亡指数最大,而后细胞凋亡指数减小,并维持在相对稳定的水平。说明甘肃鼢鼠视网膜细胞凋亡主要发生在出生后两周之内,14日龄时为凋亡峰,而后凋亡指数减小。3.0日龄、3日龄、5日龄、7日龄、9日龄、11日龄、14日龄甘肃鼢鼠各视觉核团Bax蛋白和Bcl-2蛋白的比率呈增加趋势,14日龄时Bax蛋白和Bcl-2蛋白的比率最大。这说明甘肃鼢鼠出生后两周时间内,各视觉核团细胞凋亡程度逐渐增大,14日龄时细胞凋亡程度最大。4.14日龄往后甘肃鼢鼠各视觉核团Bax蛋白和Bcl-2蛋白的比率逐渐减小,并维持在相对稳定的水平。这说明当机体内环境达到稳定后,细胞凋亡也随之维持在一个相对稳定的水平。而且这一结果可能和睁眼有关。5.每一年龄段甘肃鼢鼠视觉核团中外侧膝状体背侧核、外侧膝状体腹侧核中Bax蛋白和bcl-2蛋白的表达量较其它核团多。这说明在视觉信号转导过程中,外侧膝状体起着非常重要的作用。总之,本研究结果表明甘肃鼢鼠视觉系统细胞凋亡主要发生在出生后两周时间;14日龄时细胞凋亡值最大,为凋亡峰；随后细胞凋亡减少,并保持在一个相对稳定的水平。更多还原

【Abstract】 The significant differences shown in the evolution of the animals’visual system living in special circumstances is remarkable.As the Cansu zokor(Myospalax cansus) living in the dark underground tunnels over its life, the spatial pattern of life had a profound effect to the structure of their visual system and physiological functions. As a result of the long evolutionary adaptation, the visual system structure and function of the shape changes dramatically, the most notable of which is smaller eyes,and visual degradation. Studies show that the structure of the retina of Myospalax cansus is integrity.Why is Myospalx cansus’visual degradation and the process is still unclear.So we study Myospalax cansus for visual system to study apoptosis by use of cytology,immunohistochemistry and other methods. Results are as follows:1. From 0th day old apoptotic cells appeared in the retinal of Myospalax cansus. The apoptosis index is 26.9±0.441%. This indicates that after birth the retinal of Myospalax cansus associated with apoptosis.Apoptotic cells were in retinal rod and cone layer of the layers inward, in particular outer nuclear layer, inner nuclear layer and ganglion cell layer.This shows that the layer of rod and cone cells in each layer inward is the main visual pathway neurons.2.The apoptosis index of retinal cells gradually increased along with the dates growth of 0th,3th,5th,7th,9th,11th and 14th day old. The apoptosis index of 14th day old was the maximum, then decreased, and stabled a relative level. This shows that the apoptosis of retinal cells mainly occur within two weeks after birth and apoptotic peak appears at 14th day old, then apoptosis reduced.3. The ratio of Bax and Bcl-2 gradually increased along with the dates growth of 0th,3th,5th,7th,9th,11th and 14th day old, and the ratio of Bax and Bcl-2 in 14th day old was the largest.This shows that the degree of apoptosis gradually increased and the degree of apoptosis is the greatest in 14th day old.4. The ratios of Bax and Bcl-2 stabled a relative level. This shows that apoptosis also stable a relative level when internal environment of organism reaches stable. In addition, this result may be related with eye opening.5. The number of Bax expression of the dorsal lateral geniculate nucleus and the ventral lateral geniculate nucleus in each age section of Myospalax cansus were more than the one of other visual nucleus. This indicates that in the entire transmission process of visual information the lateral geniculate nucleus plays a extremely important role. In brief, this research indicated that apoptosis of the vision system of Myospalax cansus mainly occurres within two weeks after birth. The degree of apoptosis is the greatest in 14th day old and apoptotic peak appears at 14th day old. Then apoptosis stable a relative level.更多还原