无精子症患者的减数分裂研究

发布时间：2018-07-29 18:32

【摘要】：哺乳动物精子发生是一个受到严格调控的复杂过程,在减数分裂前期Ⅰ,同源染色体的重组将同源染色体联系在一起,从而保证了减数分裂后期Ⅰ染色体的正确分离。本研究探究了减数分裂染色体配对、联会和重组的异常对男性精子发生的影响：第一,染色体相互易位是一种常见的染色体结构异常,通常会导致男性不育,但具体机制仍不太清楚。本文利用精母细胞铺展和免疫荧光染色,对3例染色体核型分别为46,XY,t(8;15),46)X,t(Y;l)(p11.3;p31)和46,XY,t(5;7;9;13)(5q11;7p11;7P15;9q12;13p12)的无精子症患者进行了减数分裂进程、配对、联会以及重组的研究。发现与正常人相比,染色体易位患者减数分裂进程受到明显的影响,γH2AX和BRCA1定位于易位染色体不联会的区域,性染色体的遗传重组频率降低,易位的染色体和未涉及易位的染色体上的遗传重组也受到影响。这些减数分裂异常的细胞凋亡明显增加,可能因此导致了染色体易位携带者的精子发生障碍和不育。第二,虽然大多数47,XYY的男性可育,但也有部分患者表现为精子数目减少乃至无精子。本文利用免疫荧光染色,对2例染色体核型分别为48,XYY,+sSMC和47,XYY的无精子症患者的减数分裂进行了研究。与正常人相比,XYY患者的减数分裂进程受到明显影响,48,XYY,+sSMC患者性染色体的遗传重组频率明显降低,47,XYY患者出现了不同的性染色体构型,重组不仅发生在Y染色体的短臂上,在Y染色体的长臂上也观察到了重组。与常染色体的染色相似,在两条Y染色体已配对联会的区域也没有γH2AX信号。这些结果表明,精母细胞中额外的Y染色体干扰了减数分裂,从而导致了XYY患者精子发生异常和不育。第三,减数分裂同源染色体联会异常可导致精子发生停滞,进而引起男性不育。本文利用免疫荧光染色等,对无精子症患者的睾丸活检组织进行了减数分裂进程、同源染色体配对、联会以及重组进行了研究。发现部分患者的所有细胞都表现出染色体配对联会异常,减数分裂停滞在粗线期。但也有一些患者,仅部分精母细胞表现为联会异常。这些结果表明,染色体联会异常是导致男性不育的一个重要因素,但不是唯一因素。
[Abstract]:Mammalian spermatogenesis is a complex process under strict regulation. In meiotic Prophase I, homologous chromosomes are linked by recombination of homologous chromosomes, thus ensuring the correct separation of chromosomes I in meiotic anaphase. This study explored the effects of meiotic chromosomal pairing, synaptic and recombination abnormalities on male spermatogenesis: first, chromosomal translocation is a common chromosomal structural abnormality that usually leads to male infertility. But the exact mechanism remains unclear. By means of spermatocyte spreading and immunofluorescence staining, the meiosis process, pairing, synapsis and recombination of three cases of azoospermia with chromosome karyotypes 46 (46) XYT (p11.3p31) and 46 XYT (5q117p117P159q1213p12) were studied by means of spermatocyte spreading and immunofluorescence staining. It was found that the process of meiosis in patients with chromosome translocation was significantly affected compared with that in normal subjects. 纬 H2AX and BRCA1 were located in the regions of chromosomal disjunction of translocation, and the frequency of genetic recombination of sex chromosomes was decreased. Genetic recombination on translocation chromosomes and chromosomes not involved in translocation is also affected. These abnormal meiosis increased apoptosis, which may lead to sperm dysfunction and infertility in chromosome translocation carriers. Second, while most of the 47 XYY males were fertile, some patients showed decreased sperm count and even azoospermia. The meiosis of two cases of azoospermia with chromosome karyotypes of 48 XYY, sSMC and 47 XYY were studied by immunofluorescence staining. The process of meiosis in XYY patients was significantly affected compared with that in normal controls. The frequency of genetic recombination of sex chromosomes in sSMC patients was significantly lower than that in normal controls. Different sexual chromosomal configurations appeared in patients with XYY. The recombination occurred not only on the short arm of Y chromosome, but also on the short arm of Y chromosome. Recombination was also observed on the long arm of the Y chromosome. Similar to autosomal staining, there is no 纬 H2AX signal in the region where the two Y chromosomes have paired synapses. These results suggest that the extra Y chromosome in spermatocytes interferes with meiosis, resulting in abnormal spermatozoa and infertility in XYY patients. Third, abnormal meiotic homologous chromosomal synapsis may lead to sperm stagnation, which can lead to male infertility. The process of meiosis homologous chromosome pairing synapsis and recombination of testicular biopsy tissues in azoospermia patients were studied by immunofluorescence staining. It was found that all the cells in some patients showed chromosomal pairing synaptic abnormalities and meiosis stagnated in the coarse-line phase. However, in some patients, only some spermatocytes showed synaptic abnormalities. These results suggest that chromosomal abnormalities are an important, but not the only, cause of male infertility.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：R698.2

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