转录因子Nkx2.5、ISL-1的表达与小鼠胚胎心脏的早期发育

发布时间：2018-01-11 01:17

本文关键词：转录因子Nkx2.5、ISL-1的表达与小鼠胚胎心脏的早期发育　出处：《山西医科大学》2010年硕士论文　论文类型：学位论文

【摘要】： 研究背景：胚胎心脏的形态发生受不同信号系统和转录因子的调节,在独特的信号系统和转录因子调节下,构成第一生心区的胚盘头端两侧生心中胚层随胚盘卷折,在腹侧中央融合为原始心管,分化为成体心脏左心室的原基,而胚胎心脏的流出道、右心室、部分心房则由前肠腹侧,称之为第二生心区的间充质分化为心肌前体细胞,进而分化为心肌细胞,不断添加到心管的动脉端和静脉端而形成。应用转基因和基因敲除等技术发现,转录因子Nkx2.5和ISL-1是调控第一和第二生心区心肌前体细胞分化发育的重要蛋白,Nkx2.5和ISL-1基因突变或基因敲除引发先天性心脏畸形或胚胎死亡,但Nkx2.5和ISL-1蛋白在正常胚胎心脏早期发育过程中的表达差异、时空表达规律以及在第二生心区的时空分布特点尚未见系统报道。探讨心脏形态发生过程中转录因子Nkx2.5,ISL-1蛋白在第一、第二生心区以及心脏发育早期的时空表达特点,可以为进一步研究心脏发育机制提供可靠的实验依据。研究目的：探讨转录因子Nkx2.5、ISL-1的表达和小鼠胚胎早期心脏发育的关系。研究方法：胚龄7.5-13d小鼠胚胎心脏连续石蜡切片,用抗α-平滑肌肌动蛋白(a-SMA)抗体,抗心肌肌球蛋白重链(MHC)抗体,抗转录因子ISL-1抗体,抗Nkx2.5抗体,进行免疫组织化学染色。研究结果：小鼠胚胎发育第7.5d,转录因子Nkx2.5在生心板显较强表达,而心肌特异性蛋白MHC及SMA的表达明显滞后。胚龄8-12d小鼠胚胎,随心脏外形建立,Nkx2.5与MHC的表达模式趋于相同,在心脏各部表达逐渐增强。IS1-1开始表达于胚龄8d时原始心管的心背系膜及前肠腹侧、心包腔背侧壁脏壁中胚层间充质。胚龄9d,Nkx2.5阳性表达从原始心管动脉端延伸至咽周围心包腔背侧壁脏壁中胚层及轴旁中胚层,参与流出道心肌的发育。胚胎发育10d后,大部分心背系膜消失,ISL-1阳性间充质细胞的数量随发育明显增加,在前肠腹侧形成连续的ISL-1阳性细胞带,将流出道远端和心房心背系膜相连。胚龄11-12d,心管经右侧成襻等形态发生过程,心脏外形基本建立,流出道远端出现Nkx2.5和MHC表达阴性,SMA和ISL-1表达阳性区域。ISL-1阳性细胞的数量在胚胎11-12d达顶峰,尤以动脉端数量增加明显。胚胎发育13d后,Nkx2.5和ISL-1在心脏和前肠腹侧间充质的表达强度下降。研究结论：Nkx2.5是原始生心区生心板心肌前体细胞表达较早的特异性标记蛋白。Nkx2.5在第二生心区的表达有时空特异性,主要限于胚胎发育第9d,心管头端咽周脏壁中胚层和轴旁中胚层,是第二生心区心肌前体细胞亚群,参与流出道心肌发育。第二生心区ISL-1阳性心肌前体细胞出现于胚胎发育第8d的心背系膜和前肠腹侧脏壁中胚层,其数量在胚胎11-12d达顶峰,提示小鼠胚胎发育8-12d是第二生心区心肌前体细胞向心肌分化并向发育中的心脏添加心肌细胞,驱动心管完成心脏成襻以及形态发生过程的关键时期。胚胎发育11-12d,第二生心区间充质细胞开始分化为升主动脉和肺动脉干的平滑肌。
[Abstract]:Background: the morphology of cardiac embryogenesis regulated by different transcription factors and signaling system, with the regulation of signal system and unique transcription factor, a life of heart area blastoderm head end on both sides of cardiogenic mesoderm with the blastoderm folded, primitive heart tube in the ventral central fusion, differentiate into the left ventricle of the heart. Fetal heart primordia, and right ventricular outflow tract, atria part from ventral to the foregut, called the second heart field mesenchymal differentiation into myocardial precursor cells, and then differentiated into myocardial cells, continue to add to the arterial and venous end to end heart tube formation. Application of transgenic and knockout technology found that the transcription factor Nkx2.5 and ISL-1 protein is an important regulation of the first and second heart myocardial precursor cells differentiation, Nkx2.5 and ISL-1 gene mutation or gene knockout lead to congenital heart malformations or embryo death, but Nkx2.5 Differential expression of ISL-1 protein in normal and early embryonic development in the process of the heart, and the temporal and spatial expression of the heart in second spatial distribution characteristics have not been reported. The transcription factor Nkx2.5 on heart morphogenesis, ISL-1 protein in the first and second heart field and early heart development the spatiotemporal expression characteristics, can provide reliable experimental basis for further study on the mechanism of heart development.
Objective: To investigate the relationship between the expression of transcription factor Nkx2.5, ISL-1 and the early embryonic development of mouse embryos.
Research methods: embryonic heart 7.5-13d mice embryo continuous paraffin section, using anti alpha smooth muscle actin (a-SMA) antibody, anti cardiac myosin heavy chain (MHC) antibody, anti transcription factor ISL-1 antibody, anti Nkx2.5 antibody, immunohistochemical staining.
Results: the 7.5d mouse embryo development, transcription factor Nkx2.5 in heart plate significantly strong expression and expression of cardiac specific protein MHC and SMA was significantly delayed. 8-12d embryonic mouse embryos, with heart shape, the expression pattern of Nkx2.5 and MHC tend to be the same, in the heart of the expression of.IS1-1 increased gradually began to express in dorsal mesocardium and ventral foregut detected 8D primitive heart tube, dorsal pericardial cavity splanchnic mesoderm derived mesenchymal 9D. The embryo age, the positive expression of Nkx2.5 in arteries from primitive heart tube end is extended to peripharyngeal pericardial cavity dorsal ectoderm splanchnic mesoderm and paraxial, participate in the cardiac outflow tract the development of embryo development. After 10d, most dorsal mesocardium disappeared, the number of ISL-1 positive mesenchymal cells increased significantly with the development, the formation of ISL-1 positive cells in a continuous band ventral to the foregut, the distal part of the outflow tract and atrial dorsal mesocardium embryonic heart connected. 11-12d Tube loop morphogenesis via right heart shape, basically established, the distal part of the outflow tract of Nkx2.5 and negative expression of MHC, SMA and ISL-1 expression of the number of positive area of.ISL-1 positive cells peaked in embryonic 11-12d, especially in the artery end increased obviously. The embryonic development of 13D, decreased expression levels of Nkx2.5 and ISL-1 in the heart and ventral to the foregut mesenchyme.
Conclusion: Nkx2.5 is the primary heart field cardiac precursor cells in the early marker of.Nkx2.5 has spatio-temporal expression in the second heart field, mainly confined to the embryonic development of the 9D, the heart tube end peripharyngeal Zangbi mesoderm and paraxial mesoderm, second heart myocardial precursor cells in the subgroup of outflow tract myocardial development. Second heart ISL-1 positive cardiac progenitor cells appeared dorsal mesocardium and ventral foregut visceral mesoderm in embryonic development in 8D, the number reached a peak in the embryo development of mouse embryo 8-12d 11-12d, that is second heart myocardium before heart somatic cell differentiation into cardiomyocytes in addition to the development of myocardial cells, driving the heart tube to complete heart into a critical period and loop morphogenesis of embryonic development. 11-12d, second heart field mesenchymal cells begin to differentiate into ascending aorta and pulmonary artery smooth Smooth muscle.

【学位授予单位】：山西医科大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：R329.1

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