甘肃鼢鼠（Myospalax cansus）视觉系统细胞凋亡研究

【作者】 郑燕燕；

【导师】 李金钢；

【作者基本信息】 陕西师范大学 ， 动物学， 2008， 硕士

【摘要】 视觉系统在动物通讯中占据主导地位,有关其适应进化一直是人们关注的焦点。营严格地下洞道生活的啮齿动物,由于适应地下黑暗的生活环境,其视觉系统的形态结构、功能等在进化中表现出高度的趋同现象,如视器变小,视觉退化乃至消失等。这些特征为研究地下啮齿动物视觉系统的适应进化提供了十分理想的实验材料,也将对地下啮齿动物视觉系统适应进化机制的研究起积极促进作用。本研究以甘肃鼢鼠(Myospalax cansus)为材料,运用吉姆萨—瑞氏染色法观察不同日龄甘肃鼢鼠视网膜细胞的凋亡形态和数量、免疫组织化学法对各视觉核团中Bax、Bcl-2表达量进行测定,探讨甘肃鼢鼠视觉系统细胞凋亡情况。结果如下:1.从0日龄开始甘肃鼢鼠视网膜内出现凋亡细胞,凋亡指数为:26.9±0.441%,这说明甘肃鼢鼠出生后其视网膜就伴随着细胞凋亡。2.大多数凋亡细胞出现在视网膜视杆视锥层向内的各层,特别是外核层、内核层和神经节细胞层,这说明视杆视锥层及其向内的各层细胞才是视觉通路中的主要神经元。3.0日龄、7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,并维持在相对稳定水平,说明甘肃鼢鼠视网膜细胞主要在出生后两周的时间内发生凋亡,14日龄时为凋亡峰,而后凋亡又减少。4.0日龄、7日龄、14日龄甘肃鼢鼠视觉核团Bax和Bcl-2的比率呈增加趋势,14日龄时Bax和Bcl-2的比率最大。这说明甘肃鼢鼠出生后两周,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。5.14日龄往后甘肃鼢鼠视觉核团Bax和Bcl-2的比率维持在相对稳定的水平,这说明当机体的内环境达到稳定后,细胞凋亡也随之维持在一个相对稳定的水平。另外,这一结果可能还与睁眼有关。6.每一年龄段甘肃鼢鼠外侧膝状体背侧核、外侧膝状体腹侧核Bax蛋白表达量较其它核团多。这说明在整个视觉信息的传递过程中,外侧膝状体起着极其重要的作用。总之,本研究表明甘肃鼢鼠视觉系统的细胞凋亡主要发生在出生后两周内;14日龄时细胞凋亡程度最大,为凋亡峰;而后细胞凋亡保持在一个相对稳定的水平。更多还原

【Abstract】 Visual system in animal’s communications occupys a dominant position,and its evolutionary adaptation has been the focus of attention.Owning to adapting to subterranean dark ecotope, morphologic structures and functions of visual system in subterranean rodents show high convergence,such as small visual organs,regressive visual ability and even no such ability,which provides ideal materials for the studies on visual system evolution of these animals.And it will assist in revealing the adaptive evolutionary mechanism of visual system of subterranean rodents.Using Giemsa-Wright staining to observe the form and the number of apoptotic cells of retinal and immunohistochemical method to measure the number of Bax and Bcl-2 of every visual nucleus in different day old groups of Myospalax cansus,and to explore the apoptosis of visual system.The 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.2.Most of apoptotic cells in the retina appeared inside photoreceptor outer segment, especially outer nuclear layer,inner nuclear layer and ganglion cell layer.This indicates that cells which inside photoreceptor outer segment are the major neurons of visual pathway.3.The apoptosis index of retinal cells gradually increased along with the dates growth of 0th, 7th 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.4.The ratio of Bax and Bcl-2 gradually increased along with the dates growth of 0th,7th and 14th day old.,and the ratio of Bax and Bcl-2 was the largest.This shows that the degree of apoptosis gradually increased and the degree of apoptosis is the greatest in 14th day old.5.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.6.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 indicates 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